From The Niels Bohr Institute [Niels Bohr Institutet] (DK): “Danish quantum physicists make nanoscopic advance of colossal significance”

From The Niels Bohr Institute [Niels Bohr Institutet] (DK)

at

University of Copenhagen [Københavns Universitet] [UCPH] (DK)

1.26.23
Peter Lodahl
Professor
Niels Bohr Institute
University of Copenhagen
Mobile: + 45 20 56 53 03
Email: lodahl@nbi.ku.dk

Alexey Tiranov
Postdoc
Niels Bohr Institute
University of Copenhagen
Phone: + 45 35 33 51 39
Email: alexey.tiranov@nbi.ku.dk

Michael Skov Jensen
Journalist and team coordinator
The Faculty of Science
University of Copenhagen
Mobile: + 45 93 56 58 97
msj@science.ku.dk

In a new breakthrough, researchers at the University of Copenhagen, in collaboration with Ruhr University Bochum, have solved a problem that has caused quantum researchers headaches for years. The researchers can now control two quantum light sources rather than one. Trivial as it may seem to those uninitiated in quantum, this colossal breakthrough allows researchers to create a phenomenon known as quantum mechanical entanglement. This in turn, opens new doors for companies and others to exploit the technology commercially.

Part of the team behind the invention. From left: Peter Lodahl, Anders Sørensen, Vasiliki Angelopoulou, Ying Wang, Alexey Tiranov, Cornelis van Diepen. Photo: Ola J. Joensen.

Going from one to two is a minor feat in most contexts. But in the world of quantum physics, doing so is crucial. For years, researchers around the world have strived to develop stable quantum light sources and achieve the phenomenon known as quantum mechanical entanglement – a phenomenon, with nearly sci-fi-like properties, where two light sources can affect each other instantly and potentially across large geographic distances. Entanglement is the very basis of quantum networks and central to the development of an efficient quantum computer.

Today, researchers from the Niels Bohr Institute published a new result in the highly esteemed journal Science [below], in which they succeeded in doing just that. According to Professor Peter Lodahl, one of the researchers behind the result, it is a crucial step in the effort to take the development of quantum technology to the next level and to “quantize” society’s computers, encryption and the internet.

“We can now control two quantum light sources and connect them to each other. It might not sound like much, but it’s a major advancement and builds upon the past 20 years of work. By doing so, we’ve revealed the key to scaling up the technology, which is crucial for the most ground-breaking of quantum hardware applications,” says Professor Peter Lodahl, who has conducted research the area since 2001.

The magic all happens in a so-called nanochip – which is not much larger than the diameter of a human hair – that the researchers also developed in recent years.

Illustration of two a chip comprising two entangled quantum light sources. Credit: NBI.

Quantum sources overtake the world’s most powerful computer

Peter Lodahl’s group is working with a type of quantum technology that uses light particles, called photons, as micro transporters to move quantum information about.

While Lodahl’s group is a leader in this discipline of quantum physics, they have only been able to control one light source at a time until now. This is because light sources are extraordinarily sensitive to outside “noise”, making them very difficult to copy. In their new result, the research group succeeded in creating two identical quantum light sources rather than just one.

“Entanglement means that by controlling one light source, you immediately affect the other. This makes it possible to create a whole network of entangled quantum light sources, all of which interact with one another, and which you can get to perform quantum bit operations in the same way as bits in a regular computer, only much more powerfully,” explains postdoc Alexey Tiranov, the article’s lead author.

This is because a quantum bit can be both a 1 and 0 at the same time, which results in processing power that is unattainable using today’s computer technology. According to Professor Lodahl, just 100 photons emitted from a single quantum light source will contain more information than the world’s largest supercomputer can process.

By using 20-30 entangled quantum light sources, there is the potential to build a universal error-corrected quantum computer – the ultimate “holy grail” for quantum technology, that large IT companies are now pumping many billions into.

Other actors will build upon the research

According to Lodahl, the biggest challenge has been to go from controlling one to two quantum light sources. Among other things, this has made it necessary for researchers to develop extremely quiet nanochips and have precise control over each light source.

With the new research breakthrough, the fundamental quantum physics research is now in place. Now it is time for other actors to take the researchers’ work and use it in their quests to deploy quantum physics in a range of technologies including computers, the internet and encryption.

“It is too expensive for a university to build a setup where we control 15-20 quantum light sources. So, now that we have contributed to understanding the fundamental quantum physics and taken the first step along the way, scaling up further is very much a technological task,” says Professor Lodahl.

The research was conducted at the Danish National Research Foundation’s “Center of Excellence for Hybrid Quantum Networks (Hy-Q)” and is a collaboration between Ruhr University Bochum in Germany and the the University of Copenhagen’s Niels Bohr Institute.

Science

See the full article here .

Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct. Use “Reply”.

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Stem Education Coalition

Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct.

The Niels Bohr Institutet (DK) is a research institute of the Københavns Universitet [UCPH] (DK). The research of the institute spans astronomy, geophysics, nanotechnology, particle physics, quantum mechanics and biophysics.

The Institute was founded in 1921, as the Institute for Theoretical Physics of the Københavns Universitet [UCPH] (DK), by the Danish theoretical physicist Niels Bohr, who had been on the staff of the University of Copenhagen since 1914, and who had been lobbying for its creation since his appointment as professor in 1916. On the 80th anniversary of Niels Bohr’s birth – October 7, 1965 – the Institute officially became The Niels Bohr Institutet (DK). Much of its original funding came from the charitable foundation of the Carlsberg brewery, and later from the Rockefeller Foundation.

During the 1920s, and 1930s, the Institute was the centre of the developing disciplines of atomic physics and quantum physics. Physicists from across Europe (and sometimes further abroad) often visited the Institute to confer with Bohr on new theories and discoveries. The Copenhagen interpretation of quantum mechanics is named after work done at the Institute during this time.

On January 1, 1993 the institute was fused with the Astronomic Observatory, the Ørsted Laboratory and the Geophysical Institute. The new resulting institute retained the name Niels Bohr Institutet (DK).

Københavns Universitet (UCPH) (DK) is the oldest university and research institution in Denmark. Founded in 1479 as a studium generale, it is the second oldest institution for higher education in Scandinavia after Uppsala University (1477). The university has 23,473 undergraduate students, 17,398 postgraduate students, 2,968 doctoral students and over 9,000 employees. The university has four campuses located in and around Copenhagen, with the headquarters located in central Copenhagen. Most courses are taught in Danish; however, many courses are also offered in English and a few in German. The university has several thousands of foreign students, about half of whom come from Nordic countries.

The university is a member of the International Alliance of Research Universities (IARU), along with University of Cambridge (UK), Yale University , The Australian National University (AU), and University of California-Berkeley , amongst others. The 2016 Academic Ranking of World Universities ranks the University of Copenhagen as the best university in Scandinavia and 30th in the world, the 2016-2017 Times Higher Education World University Rankings as 120th in the world, and the 2016-2017 QS World University Rankings as 68th in the world. The university has had 9 alumni become Nobel laureates and has produced one Turing Award recipient.

From The Fu Foundation School of Engineering and Applied Science At Columbia University: “High-performance Visible-light Lasers that Fit on a Fingertip”

From The Fu Foundation School of Engineering and Applied Science

At

Columbia University

1.4.23
Holly Evarts,
Director of Strategic Communications and Media Relations
347-453-7408 (c)
212-854-3206 (o)
holly.evarts@columbia.edu

In a significant advance for impactful technologies such as quantum optics and laser displays for AR/VR, Columbia Engineering’s Lipson Nanophotonics Group has invented the first tunable and narrow line-width chip-scale lasers for visible wavelengths shorter than red.

Illustration of the integrated laser platform created by the Lipson Nanophotonics Group, where a single chip generates narrow linewidth and tunable visible light covering all colors. Credit: Myles Marshall/Columbia Engineering.

As technologies keep advancing at exponential rates and demand for new devices rises accordingly, miniaturizing systems into chips has become increasingly important. Microelectronics has changed the way we manipulate electricity, enabling sophisticated electronic products that are now an essential part of our daily lives. Similarly, integrated photonics has been revolutionizing the way we control light for applications such as data communications, imaging, sensing, and biomedical devices. By routing and shaping light using micro- and nanoscale components, integrated photonics shrinks full optical systems into the size of tiny chips. 

Despite its success, integrated photonics has been missing a key component to achieve complete miniaturization: high-performance chip-scale lasers. While some progress has been made on near-infrared lasers, the visible-light lasers that currently feed photonic chips are still benchtop and expensive. Since visible light is essential for a wide range of applications including quantum optics, displays, and bioimaging, there is a need for tunable and narrow-linewidth chip-scale lasers emitting light of different colors.

Researchers at Columbia Engineering’s Lipson Nanophotonics Group have created visible lasers of very pure colors from near-ultraviolet to near-infrared that fit on a fingertip. The colors of the lasers can be precisely tuned and extremely fast – up to 267 petahertz per second, which is critical for applications such as quantum optics. The team is the first to demonstrate chip-scale narrow-linewidth and tunable lasers for colors of light below red — green, cyan, blue, and violet. These inexpensive lasers also have the smallest footprint and shortest wavelength (404 nm) of any tunable and narrow-linewidth integrated laser emitting visible light. The study, which was first presented at the CLEO 2021 post-deadline session on May 14, 2021, was published online December 23, 2022, by Nature Photonics [below]. 

“What’s exciting about this work is that we’ve used the power of integrated photonics to break the existing paradigm that high-performance visible lasers need to be benchtop and cost tens of thousands of dollars,” says the study’s lead author Mateus Corato Zanarella, a PhD student who works with Michal Lipson, Higgins Professor of Electrical Engineering and professor of Applied Physics. “Until now, it’s been impossible to shrink and mass-deploy technologies that require tunable and narrow-linewidth visible lasers. A notable example is quantum optics, which demands high-performance lasers of several colors in a single system. We expect that our findings will enable fully integrated visible light systems for existing and new technologies.” 

Benefits of emitting wavelengths below red

The importance of lasers emitting wavelengths shorter than red is clear when you consider some important applications. Displays, for example, require red, green, and blue light simultaneously to compose any color. In quantum optics, green, blue, and violet lasers are used for trapping and cooling atoms and ions. In underwater Lidar (Light Detection and Ranging), green or blue light is needed to avoid water absorption. However, at wavelengths shorter than red, the coupling and propagation losses of photonic integrated circuits increase significantly, which has prevented the realization of high-performance lasers at these colors. 

Solving coupling and propagation loss issues

The researchers solved the coupling loss problem by choosing Fabry-Perot (FP) diodes as the light sources, which minimizes the impact of the losses on the performance of the chip-scale lasers. Unlike other strategies that use different types of sources, the team’s approach enables the realization of lasers at record-short wavelengths (404 nm) while also providing scalability to high optical powers, FP laser diodes are inexpensive and compact solid-state lasers widely used in research and industry. However, they emit light of several wavelengths simultaneously and are not easily tunable, preventing them to be directly used for applications requiring pure and precise lasers. By combining them with the specially designed photonic chip, the researchers are able to modify the laser emission to be single-frequency, narrow-linewidth, and widely tunable. 

The team overcame the propagation loss issue by designing a platform that minimizes both the material absorption and surface scattering losses simultaneously for all the visible wavelengths. To guide the light, they used silicon nitride, a dielectric widely used in the semiconductor industry that is transparent for visible light of all colors. Even though there is minimal absorption, the light still experiences loss due to unavoidable roughness from the fabrication processes. The team solved this problem by designing a photonic circuit with a special type of ring resonator. The ring has a variable width along its circumference, allowing for single-mode operation characteristic of narrow waveguides, and low loss characteristic of wide waveguides. The resulting photonic circuit provides a wavelength-selective optical feedback to the FP diodes that forces the laser to emit at a single desired wavelength with very narrow linewidth.

“By combining these intricately designed pieces, we were able to build a robust and versatile platform that is scalable and works for all colors of light,” said Corato Zanarella. 

Revolutionizing technologies

“As a laser manufacturer we recognize that integrated photonics will have a tremendous impact on our industry and will enable a new generation of applications that have so far been impossible,” said Chris Haimberger, director of Laser Technology, TOPTICA Photonics, Inc. “This work represents an important step forward in the pursuit of compact and tunable visible lasers that will power future developments in computing, medicine, and industry.”

Next steps

The researchers, who have filed a provisional patent for their technology, are now exploring how to optically and electrically package the lasers to turn them into standalone units and use them as sources in chip-scale visible light engines, quantum experiments, and optical clocks.

“In order to move forward, we have to be able to miniaturize and scale these systems, enabling them to eventually be incorporated in mass-deployed technologies,” said Lipson, a pioneer in silicon photonics whose research has strongly shaped the field from its inception decades ago, with foundational contributions in the active and passive devices that are part of any current photonic chip. She added, “Integrated photonics is an exciting field that is truly revolutionizing our world, from optical telecommunications to quantum information to biosensing.”

Science paper:
Nature Photonics

See the full article here .

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The Columbia University Fu Foundation School of Engineering and Applied Science is the engineering and applied science school of Columbia University. It was founded as the School of Mines in 1863 and then the School of Mines, Engineering and Chemistry before becoming the School of Engineering and Applied Science. On October 1, 1997, the school was renamed in honor of Chinese businessman Z.Y. Fu, who had donated $26 million to the school.

The Fu Foundation School of Engineering and Applied Science maintains a close research tie with other institutions including National Aeronautics and Space Administration, IBM, Massachusetts Institute of Technology, and The Earth Institute. Patents owned by the school generate over $100 million annually for the university. Faculty and alumni are responsible for technological achievements including the developments of FM radio and the maser.

The School’s applied mathematics, biomedical engineering, computer science and the financial engineering program in operations research are very famous and ranked high. The current faculty include 27 members of the National Academy of Engineering and one Nobel laureate. In all, the faculty and alumni of Columbia Engineering have won 10 Nobel Prizes in physics, chemistry, medicine, and economics.

The school consists of approximately 300 undergraduates in each graduating class and maintains close links with its undergraduate liberal arts sister school Columbia College which shares housing with SEAS students.

Original charter of 1754

Included in the original charter for Columbia College was the direction to teach “the arts of Number and Measuring, of Surveying and Navigation […] the knowledge of […] various kinds of Meteors, Stones, Mines and Minerals, Plants and Animals, and everything useful for the Comfort, the Convenience and Elegance of Life.” Engineering has always been a part of Columbia, even before the establishment of any separate school of engineering.

An early and influential graduate from the school was John Stevens, Class of 1768. Instrumental in the establishment of U.S. patent law. Stevens procured many patents in early steamboat technology; operated the first steam ferry between New York and New Jersey; received the first railroad charter in the U.S.; built a pioneer locomotive; and amassed a fortune, which allowed his sons to found the Stevens Institute of Technology.

When Columbia University first resided on Wall Street, engineering did not have a school under the Columbia umbrella. After Columbia outgrew its space on Wall Street, it relocated to what is now Midtown Manhattan in 1857. Then President Barnard and the Trustees of the University, with the urging of Professor Thomas Egleston and General Vinton, approved the School of Mines in 1863. The intention was to establish a School of Mines and Metallurgy with a three-year program open to professionally motivated students with or without prior undergraduate training. It was officially founded in 1864 under the leadership of its first dean, Columbia professor Charles F. Chandler, and specialized in mining and mineralogical engineering. An example of work from a student at the School of Mines was William Barclay Parsons, Class of 1882. He was an engineer on the Chinese railway and the Cape Cod and Panama Canals. Most importantly he worked for New York, as a chief engineer of the city’s first subway system, the Interborough Rapid Transit Company. Opened in 1904, the subway’s electric cars took passengers from City Hall to Brooklyn, the Bronx, and the newly renamed and relocated Columbia University in Morningside Heights, its present location on the Upper West Side of Manhattan.

Columbia University was founded in 1754 as King’s College by royal charter of King George II of England. It is the oldest institution of higher learning in the state of New York and the fifth oldest in the United States.

University Mission Statement

Columbia University is one of the world’s most important centers of research and at the same time a distinctive and distinguished learning environment for undergraduates and graduate students in many scholarly and professional fields. The University recognizes the importance of its location in New York City and seeks to link its research and teaching to the vast resources of a great metropolis. It seeks to attract a diverse and international faculty and student body, to support research and teaching on global issues, and to create academic relationships with many countries and regions. It expects all areas of the University to advance knowledge and learning at the highest level and to convey the products of its efforts to the world.

Columbia University is a private Ivy League research university in New York City. Established in 1754 on the grounds of Trinity Church in Manhattan Columbia is the oldest institution of higher education in New York and the fifth-oldest institution of higher learning in the United States. It is one of nine colonial colleges founded prior to the Declaration of Independence, seven of which belong to the Ivy League. Columbia is ranked among the top universities in the world by major education publications.

Columbia was established as King’s College by royal charter from King George II of Great Britain in reaction to the founding of Princeton College. It was renamed Columbia College in 1784 following the American Revolution, and in 1787 was placed under a private board of trustees headed by former students Alexander Hamilton and John Jay. In 1896, the campus was moved to its current location in Morningside Heights and renamed Columbia University.

Columbia scientists and scholars have played an important role in scientific breakthroughs including brain-computer interface; the laser and maser; nuclear magnetic resonance; the first nuclear pile; the first nuclear fission reaction in the Americas; the first evidence for plate tectonics and continental drift; and much of the initial research and planning for the Manhattan Project during World War II. Columbia is organized into twenty schools, including four undergraduate schools and 15 graduate schools. The university’s research efforts include the Lamont–Doherty Earth Observatory, the Goddard Institute for Space Studies, and accelerator laboratories with major technology firms such as IBM. Columbia is a founding member of the Association of American Universities and was the first school in the United States to grant the M.D. degree. With over 14 million volumes, Columbia University Library is the third largest private research library in the United States.

The university’s endowment stands at $11.26 billion in 2020, among the largest of any academic institution. As of October 2020, Columbia’s alumni, faculty, and staff have included: five Founding Fathers of the United States—among them a co-author of the United States Constitution and a co-author of the Declaration of Independence; three U.S. presidents; 29 foreign heads of state; ten justices of the United States Supreme Court, one of whom currently serves; 96 Nobel laureates; five Fields Medalists; 122 National Academy of Sciences members; 53 living billionaires; eleven Olympic medalists; 33 Academy Award winners; and 125 Pulitzer Prize recipients.

From The University of São Paulo [Universidade de São Paulo](BR) Via “phys.org” : “Researchers develop a light source that produces two entangled light beams”

From The University of São Paulo [Universidade de São Paulo](BR)

Via

“phys.org”

1.3.23
José Tadeu Arantes

The optical parametric oscillator (OPO) used in the study. Credit: Alvaro Montaña Guerrero.

Scientists are increasingly studying quantum entanglement, which occurs when two or more systems are created or interact in such a manner that the quantum states of some cannot be described independently of the quantum states of the others. The systems are correlated even when they are separated by a large distance. The significant potential for applications in encryption, communications and quantum computing spurs research. The difficulty is that when the systems interact with their surroundings, they almost immediately become disentangled.

In the latest study by the Laboratory for Coherent Manipulation of Atoms and Light (LMCAL) at the University of São Paulo’s Physics Institute (IF-USP) in Brazil, the researchers succeeded in developing a light source that produced two entangled light beams. Their work is published in Physical Review Letters [below].

“This light source was an optical parametric oscillator, or OPO, which is typically made up of a non-linear optical response crystal between two mirrors forming an optical cavity. When a bright green beam shines on the apparatus, the crystal-mirror dynamics produces two light beams with quantum correlations,” said physicist Hans Marin Florez, last author of the article.

The problem is that light emitted by crystal-based OPOs cannot interact with other systems of interest in the context of quantum information, such as cold atoms, ions or chips, since its wavelength is not the same as those of the systems in question. “Our group showed in previous work that atoms themselves could be used as a medium instead of a crystal. We therefore produced the first OPO based on rubidium atoms, in which two beams were intensely quantum-correlated, and obtained a source that could interact with other systems with the potential to serve as quantum memory, such as cold atoms,” Florez said.

However, this was not sufficient to show the beams were entangled. In addition to the intensity, the beams’ phases, which have to do with light wave synchronization, also needed to display quantum correlations. “That’s precisely what we achieved in the new study reported in Physical Review Letters,” he said.

“We repeated the same experiment but added new detection steps that enabled us to measure the quantum correlations in the amplitudes and phases of the fields generated. As a result, we were able to show they were entangled. Furthermore, the detection technique enabled us to observe that the entanglement structure was richer than would typically be characterized. Instead of two adjacent bands of the spectrum being entangled, what we had actually produced was a system comprising four entangled spectral bands.”

In this case, the amplitudes and phases of the waves were entangled. This is fundamental in many protocols to process and transmit quantum-coded information. Besides these possible applications, this kind of light source could also be used in metrology. “Quantum correlations of intensity result in a considerable reduction of intensity fluctuations, which can enhance the sensitivity of optical sensors,” Florez said. “Imagine a party where everyone is talking and you can’t hear someone on the other side of the room. If the noise decreases sufficiently, if everyone stops talking, you can hear what someone says from a good distance away.”

Enhancing the sensitivity of atomic magnetometers used to measure the alpha waves emitted by the human brain is one of the potential applications, he added.

The article also notes an additional advantage of rubidium OPOs over crystal OPOs. “Crystal OPOs have to have mirrors that keep the light inside the cavity for longer, so that the interaction produces quantum correlated beams, whereas the use of an atomic medium in which the two beams are produced more efficiently than with crystals avoids the need for mirrors to imprison the light for such a long time,” Florez said.

Before his group conducted this study, other groups had tried to make OPOs with atoms but failed to demonstrate quantum correlations in the light beams produced. The new experiment showed there was no intrinsic limit in the system to prevent this from happening. “We discovered that the temperature of the atoms is key to observation of quantum correlations. Apparently, the other studies used higher temperatures that prevented the researchers from observing correlations,” he said.

Science paper:
Physical Review Letters

See the full article here.

Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct. Use “Reply”.

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The University of São Paulo is a public university in the Brazilian state of São Paulo. It is the largest Brazilian public university and the country’s most prestigious educational institution, the best university in Ibero-America, and holds a high reputation among world universities, being ranked 100 worldwide in reputation by the Times Higher Education World University Rankings. The University of São Paulo is involved in teaching, research and university extension in all areas of knowledge, offering a broad range of courses.

The university was founded in 1934, regrouping already existing schools in the state of São Paulo, such as the Faculdade de Direito do Largo de São Francisco (Faculty of Law), the Escola Politécnica (Engineering School) and the Escola Superior de Agricultura Luiz de Queiroz (College of Agriculture). The university’s foundation is marked by the creation in 1934 of the Faculdade de Filosofia, Ciências e Letras (Faculty of Philosophy, Sciences and Literature, 1934–1968), and has subsequently created new departments, becoming one of the largest institutions of higher education in Latin America, with approximately 90,000 enrolled students. Currently, it has eleven campuses, four of them in the city of São Paulo. The remaining campuses are in the cities of Bauru, Lorena, Piracicaba, Pirassununga, Ribeirão Preto and two in São Carlos.

Several students from the University of São Paulo have achieved important positions in Brazilian society. It was the alma mater of thirteen Brazilian presidents, such as Fernando Henrique Cardoso and Michel Temer. The USP was ranked 19th worldwide in a rank based on the number of alumni who became CEOs in the world’s 500 largest companies, and also classed in the top 100 worldwide in the Global Employability University Ranking. In terms of research, the The University of São Paulo is Brazil’s largest research institution, producing more than 25% of the scientific papers published by Brazilian researchers in high quality conferences and journals. In 2015, out of 36 subjects, the QS World University Rankings ranked The University of São Paulo in the top 50 in eight subjects (including Architecture, Geography, Dentistry, Civil Engineering, Agriculture/Forestry, Art/Design and Veterinary Science) and in the top 51-100th position in 21 more subjects (including Computer Science, Mechanical, Electrical and Chemical Engineering, Modern Languages, Physics, Chemistry and Mathematics). According to the SCImago Institutions Ranking 2021, the The University of São Paulo was ranked 26º (twenty sixth) worldwide in the first quarter of 2021. Over the years, QS also consistently ranked The University of São Paulo among the top 5 universities in the Latin world.

Today the USP has five hospitals and offers 247 undergraduate programs and 239 graduate programs in all areas of study. The university houses altogether 24 museums and galleries – with half a million visitors a year – two theaters, a cinema, a TV channel and an orchestra. The University of São Paulo welcomes people from all continents and stimulates this process via networks and consortiums (International Office – The University of São Paulo), such as Erasmus Mundus, Associação das Universidades de Língua Portuguesa, and Rede Magalhães (SMILE – Student Mobility in Latin America, Caribbean and Europe), among others.

According to Academic Ranking of World Universities, The University of São Paulo was classified in the first place, regarding the number of doctorates awarded during 2011. The University of São Paulo is ranked among the top 70 universities in the world, in the Ranking “Top Universities by Reputation 2013” published by Times Higher Education. According to the 2013 Academic Ranking of World Universities, the The University of São Paulo is placed in the group of the 101–151 top world universities. According to the 2020 CWTS Leiden Ranking, The University of São Paulo is ranked 7th in the world. In the 2022 QS World University Rankings, The University of São Paulo ranked 121st in the world and is ranked 2nd in Latin America. As of 2021, the University of São Paulo is the first Latin American institution in the Times Higher Education World University Rankings to be ranked at 201-250th.

From The Swiss Federal Institute of Technology in Lausanne [EPFL-École Polytechnique Fédérale de Lausanne] (CH): “New quantum technology combines free electrons and photons”

From The Swiss Federal Institute of Technology in Lausanne [EPFL-École Polytechnique Fédérale de Lausanne] (CH)

8.24.22
Andrea Testa
Guanhao Huang

Scientists from EPFL, the Max Planck Institute for Multidisciplinary Sciences and the University of Göttingen have successfully created electron-photon pairs for the first time in a controlled way, using integrated photonic circuits on a chip. Using a new technique, they could precisely detect the involved particles. The findings of the study expand the toolbox of quantum technology.

Faster computers, tap-proof communication, sensors beyond standard quantum limit – quantum technologies have the potential to revolutionize our lives just as once the invention of computers or the internet. Experts worldwide are trying to implement findings from basic research into quantum technologies.

To this end, they sometimes require individual particles, such as photons – the elementary particles of light – with special properties. However, obtaining individual particles is complicated and requires complex methods. Various applications already use free electrons to generate light, such as the case in X-ray tubes.

In a new study, recently published in the journal Science [below], scientists from EPFL’s Laboratory of Photonics and Quantum Measurement, Göttingen Max Planck Institute for Multidisciplinary Sciences (MPI-NAT) and the University of Göttingen demonstrate a novel method for generating cavity-photons using free electrons, in a form of pair states. To do so, they used chip-based photonic integrated circuits in an electron microscope.

An optical chip with ring-shaped light storage, called a microring resonator, and a fiber-optic coupling. The chip is only three millimeters wide, and the ring resonator at its tip has a radius of 0.114 millimeters. © Armin Feist / Max Planck Institute for Multidisciplinary Sciences.

Fundamental Particle Physics in Electron Microscopes

In the experiment, the beam of an electron microscope passes on a built-in integrated photonic chip, consisting of a micro-ring resonator and optical fiber output ports. This new approach, using photonic structures fabricated at EPFL for transmission electron microscope (TEM) experiments performed at MPI-NAT, was established in a recent study [Nature (below)].

Whenever an electron interacts with the vacuum evanescent field of the ring resonator a photon can be generated. In this process, obeying the laws of energy and momentum conservation, the electron loses the energy quantum of a single photon. Through this interaction, the system evolves into a pair state. Thanks to a newly developed measurement method, the scientists could precisely detect simultaneously both electron energy and generated photons, revealing the underlying electron-photon pair states.

Future quantum technology with free electrons

Besides observing this process for the first time at the single particle level, these findings implement a novel concept for generating single-photon or electron. Specifically, the measurement of the pair state enables heralded particle sources, where the detection of one particle signals the generation of the other. This is necessary for many applications in quantum technology and adds to its growing toolset.

“The method opens up fascinating new possibilities in electron microscopy. In the field of quantum optics, entangled photon pairs already improve imaging. With our work, such concepts can now be explored with electrons,” explains Claus Ropers, MPI-NAT Director.

In the first proof-of-principle experiment, the researchers make use of the generated correlated electron-photon pairs for photonic mode imaging, achieving a three-orders of magnitude contrast enhancement. Dr. Yujia Yang, a postdoc at EPFL and a co-lead author of the study, adds: “We believe our work has a substantial impact on the future development in electron microscopy by harnessing the power of quantum technology.”

A particular challenge for future quantum technology is how to interface different physical systems. “For the first time, we bring free electrons into the toolbox of quantum information science. More broadly, coupling free electrons and light using integrated photonics could open the way to a new class of hybrid quantum technologies,” says Tobias Kippenberg, professor at EPFL and head of the Laboratory of Photonics and Quantum Measurement.

The work from the collaboration between the two teams contributes to the currently emerging field of free-electron quantum optics, and demonstrates a powerful experimental platform for event-based and photon-gated electron spectroscopy and imaging. “Our work represents a critical step to utilize quantum optics concepts in electron microscopy. We plan to further explore future directions like electron-heralded exotic photonic states, and noise reduction in electron microscopy,” says Guanhao Huang, PhD student at EPFL and co-lead author of the study.

Science papers:
Science
Nature 2021

See the full article here .

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EPFL campus

The Swiss Federal Institute of Technology in Lausanne [EPFL-École Polytechnique Fédérale de Lausanne] (CH) is a research institute and university in Lausanne, Switzerland, that specializes in natural sciences and engineering. It is one of the two Swiss Federal Institutes of Technology, and it has three main missions: education, research and technology transfer.

The QS World University Rankings ranks EPFL(CH) 14th in the world across all fields in their 2020/2021 ranking, whereas Times Higher Education World University Rankings ranks EPFL(CH) as the world’s 19th best school for Engineering and Technology in 2020.

EPFL(CH) is located in the French-speaking part of Switzerland; the sister institution in the German-speaking part of Switzerland is The Swiss Federal Institute of Technology ETH Zürich [Eidgenössische Technische Hochschule Zürich] (CH). Associated with several specialized research institutes, the two universities form The Domain of the Swiss Federal Institutes of Technology (ETH Domain) [ETH-Bereich; Domaine des Écoles Polytechniques Fédérales] (CH) which is directly dependent on the Federal Department of Economic Affairs, Education and Research. In connection with research and teaching activities, EPFL(CH) operates a nuclear reactor CROCUS; a Tokamak Fusion reactor; a Blue Gene/Q Supercomputer; and P3 bio-hazard facilities.

ETH Zürich, EPFL (Swiss Federal Institute of Technology in Lausanne) [École Polytechnique Fédérale de Lausanne](CH), and four associated research institutes form The Domain of the Swiss Federal Institutes of Technology (ETH Domain) [ETH-Bereich; Domaine des Écoles polytechniques fédérales] (CH) with the aim of collaborating on scientific projects.

The roots of modern-day EPFL(CH) can be traced back to the foundation of a private school under the name École Spéciale de Lausanne in 1853 at the initiative of Lois Rivier, a graduate of the École Centrale Paris (FR) and John Gay the then professor and rector of the Académie de Lausanne. At its inception it had only 11 students and the offices were located at Rue du Valentin in Lausanne. In 1869, it became the technical department of the public Académie de Lausanne. When the Académie was reorganized and acquired the status of a university in 1890, the technical faculty changed its name to École d’Ingénieurs de l’Université de Lausanne. In 1946, it was renamed the École polytechnique de l’Université de Lausanne (EPUL). In 1969, the EPUL was separated from the rest of the University of Lausanne and became a federal institute under its current name. EPFL(CH), like ETH Zürich (CH), is thus directly controlled by the Swiss federal government. In contrast, all other universities in Switzerland are controlled by their respective cantonal governments. Following the nomination of Patrick Aebischer as president in 2000, EPFL(CH) has started to develop into the field of life sciences. It absorbed the Swiss Institute for Experimental Cancer Research (ISREC) in 2008.

In 1946, there were 360 students. In 1969, EPFL(CH) had 1,400 students and 55 professors. In the past two decades the university has grown rapidly and as of 2012 roughly 14,000 people study or work on campus, about 9,300 of these being Bachelor, Master or PhD students. The environment at modern day EPFL(CH) is highly international with the school attracting students and researchers from all over the world. More than 125 countries are represented on the campus and the university has two official languages, French and English.

Organization

EPFL is organized into eight schools, themselves formed of institutes that group research units (laboratories or chairs) around common themes:

School of Basic Sciences
Institute of Mathematics
Institute of Chemical Sciences and Engineering
Institute of Physics
European Centre of Atomic and Molecular Computations
Bernoulli Center
Biomedical Imaging Research Center
Interdisciplinary Center for Electron Microscopy
MPG-EPFL Centre for Molecular Nanosciences and Technology
Swiss Plasma Center
Laboratory of Astrophysics

School of Engineering

Institute of Electrical Engineering
Institute of Mechanical Engineering
Institute of Materials
Institute of Microengineering
Institute of Bioengineering

School of Architecture, Civil and Environmental Engineering

Institute of Architecture
Civil Engineering Institute
Institute of Urban and Regional Sciences
Environmental Engineering Institute

School of Computer and Communication Sciences

Algorithms & Theoretical Computer Science
Artificial Intelligence & Machine Learning
Computational Biology
Computer Architecture & Integrated Systems
Data Management & Information Retrieval
Graphics & Vision
Human-Computer Interaction
Information & Communication Theory
Networking
Programming Languages & Formal Methods
Security & Cryptography
Signal & Image Processing
Systems

School of Life Sciences

Bachelor-Master Teaching Section in Life Sciences and Technologies
Brain Mind Institute
Institute of Bioengineering
Swiss Institute for Experimental Cancer Research
Global Health Institute
Ten Technology Platforms & Core Facilities (PTECH)
Center for Phenogenomics
NCCR Synaptic Bases of Mental Diseases

College of Management of Technology

Swiss Finance Institute at EPFL
Section of Management of Technology and Entrepreneurship
Institute of Technology and Public Policy
Institute of Management of Technology and Entrepreneurship
Section of Financial Engineering

College of Humanities

Human and social sciences teaching program

EPFL Middle East

Section of Energy Management and Sustainability

In addition to the eight schools there are seven closely related institutions

Swiss Cancer Centre
Center for Biomedical Imaging (CIBM)
Centre for Advanced Modelling Science (CADMOS)
École Cantonale d’art de Lausanne (ECAL)
Campus Biotech
Wyss Center for Bio- and Neuro-engineering
Swiss National Supercomputing Centre

From DOE’s Fermi National Accelerator Laboratory (US) : “Fermilab boasts new Theory Division”

FNAL Art Image by Angela Gonzales

From DOE’s Fermi National Accelerator Laboratory (US) , an enduring source of strength for the US contribution to scientific research worldwide.

October 8, 2021

Theoretical physics research at Fermi National Particle Accelerator Laboratory has always sparked new ideas and scientific opportunities, while at the same time supporting the large experimental group that conducts research at Fermilab. In recent years, the Theoretical Physics Department has further strengthened its position worldwide as a hub for the high-energy physics theoretical community. The department has now become Fermilab’s newest division, the Theory Division, which officially launched early this year with strong support from HEP.

This new division seeks to:

support strategic theory leadership;
promote new initiatives, as well as strengthen existing ones;
and leverage U.S. Department of Energy support through partnerships with universities and more.

“Creating the Theory Division increases the lab’s abilities to stimulate and develop new pathways to discovery,” said Fermilab Director Nigel Lockyer.

Led by Marcela Carena and her deputy Patrick Fox, this new division features three departments: Particle Theory, Astrophysics Theory and Quantum Theory. “This structure will help us focus our scientific efforts in each area and will allow for impactful contributions to existing and developing programs for the theory community,” said Carena.

Particle Theory Department

At the helm of the Particle Theory Department is Andreas Kronfeld. This department studies all aspects of theoretical particle physics, especially those areas inspired by the experimental program—at Fermilab and elsewhere. It coordinates leading national efforts, including the Neutrino Theory Network, and the migration of the lattice gauge theory program to Exascale computing platforms. Lattice quantum chromodynamics, or QCD, experts support the Muon g-2 Theory Initiative, providing a solid theory foundation for the recently announced results of the Muon g-2 experiment.

DOE’s Fermi National Accelerator Laboratory(US) Muon g-2 studio. As muons race around a ring at the Muon g-2 studio, their spin axes twirl, reflecting the influence of unseen particles.

Fermilab particle theorists, working with DOE’s Argonne National Laboratory (US) nuclear theorists, are using machine learning for developing novel event generators to precisely model neutrino-nuclear interactions, and employ lattice QCD to model multi-nucleon interactions; both are important for achieving the science goals of DUNE.

Fermilab experts on perturbative QCD use high-performance computing to tackle the complexity of simulations for experiments at the Large Hadron Collider. Fermilab theorists are strongly involved in the exploration of physics beyond the Standard Model, through model-building, particle physics phenomenology, and formal aspects of quantum field theory.

Astrophysics Theory Department

Astrophysics Theory, led by Dan Hooper, consists of researchers who work at the confluence of astrophysics, cosmology and particle physics. Fermilab’s scientists have played a key role in the development of this exciting field worldwide and continue to be deeply involved in supporting the Fermilab cosmic frontier program.

Key areas of research include dark matter, dark energy, the cosmic microwave background, large-scale structure, neutrino astronomy and axion astrophysics. A large portion of the department’s research involves numerical cosmological simulations of galaxy formation, large-scale structures and gravitational lensing. The department is developing machine-learning tools to help solve these challenging problems.

Quantum Theory Department

Led by Roni Harnik, the Quantum Theory Department has researchers working at the interface of quantum information science and high-energy physics. Fermilab theorists are working to harness the developing power of unique quantum information capabilities to address important physics questions, such as the simulation of QCD processes, dynamics in the early universe, and more generally simulating quantum field theories. Quantum-enhanced capabilities also open new opportunities to explore the universe and test theories of new particles, dark matter, gravitational waves and other new physics.

Scientists in the Quantum Theory Department are developing new algorithms for quantum simulations, and they are proposing novel methods to search for new phenomena using quantum technology, including quantum optics, atomic physics, optomechanical sensors and superconducting systems. The department works in close collaboration with both the Fermilab Superconducting Quantum Materials and Systems Center and the Fermilab Quantum Institute, as well as leads a national QuantISED theory consortium.

Looking ahead

The new Theory Division also intends to play a strong role in attracting and inspiring the next generation of theorists, training them in a data-rich environment, as well as promoting an inclusive culture that values diversity.

“The best part about being a Fermilab theorist,” said Marcela Carena, “is working with brilliant junior scientists and sharing their excitement about exploring new ideas.”

See the full article here.

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Stem Education Coalition

DOE’s Fermi National Accelerator Laboratory Wilson Hall (US).

Fermi National Accelerator Laboratory (US), located just outside Batavia, Illinois, near Chicago, is a United States Department of Energy national laboratory specializing in high-energy particle physics. Since 2007, Fermilab has been operated by the Fermi Research Alliance, a joint venture of the University of Chicago, and the Universities Research Association (URA). Fermilab is a part of the Illinois Technology and Research Corridor.

Fermilab’s Tevatron was a landmark particle accelerator; until the startup in 2008 of the Large Hadron Collider(CH) near Geneva, Switzerland, it was the most powerful particle accelerator in the world, accelerating antiprotons to energies of 500 GeV, and producing proton-proton collisions with energies of up to 1.6 TeV, the first accelerator to reach one “tera-electron-volt” energy. At 3.9 miles (6.3 km), it was the world’s fourth-largest particle accelerator in circumference. One of its most important achievements was the 1995 discovery of the top quark, announced by research teams using the Tevatron’s CDF and DØ detectors. It was shut down in 2011.

In addition to high-energy collider physics, Fermilab hosts fixed-target and neutrino experiments, such as MicroBooNE (Micro Booster Neutrino Experiment), NOνA (NuMI Off-Axis νe Appearance) and SeaQuest. Completed neutrino experiments include MINOS (Main Injector Neutrino Oscillation Search), MINOS+, MiniBooNE and SciBooNE (SciBar Booster Neutrino Experiment). The MiniBooNE detector was a 40-foot (12 m) diameter sphere containing 800 tons of mineral oil lined with 1,520 phototube detectors. An estimated 1 million neutrino events were recorded each year. SciBooNE sat in the same neutrino beam as MiniBooNE but had fine-grained tracking capabilities. The NOνA experiment uses, and the MINOS experiment used, Fermilab’s NuMI (Neutrinos at the Main Injector) beam, which is an intense beam of neutrinos that travels 455 miles (732 km) through the Earth to the Soudan Mine in Minnesota and the Ash River, Minnesota, site of the NOνA far detector. In 2017, the ICARUS neutrino experiment was moved from CERN to Fermilab.
In the public realm, Fermilab is home to a native prairie ecosystem restoration project and hosts many cultural events: public science lectures and symposia, classical and contemporary music concerts, folk dancing and arts galleries. The site is open from dawn to dusk to visitors who present valid photo identification.
Asteroid 11998 Fermilab is named in honor of the laboratory.
Weston, Illinois, was a community next to Batavia voted out of existence by its village board in 1966 to provide a site for Fermilab.

The laboratory was founded in 1969 as the National Accelerator Laboratory; it was renamed in honor of Enrico Fermi in 1974. The laboratory’s first director was Robert Rathbun Wilson, under whom the laboratory opened ahead of time and under budget. Many of the sculptures on the site are of his creation. He is the namesake of the site’s high-rise laboratory building, whose unique shape has become the symbol for Fermilab and which is the center of activity on the campus.
After Wilson stepped down in 1978 to protest the lack of funding for the lab, Leon M. Lederman took on the job. It was under his guidance that the original accelerator was replaced with the Tevatron, an accelerator capable of colliding protons and antiprotons at a combined energy of 1.96 TeV. Lederman stepped down in 1989. The science education center at the site was named in his honor.
The later directors include:

John Peoples, 1989 to 1996
Michael S. Witherell, July 1999 to June 2005
Piermaria Oddone, July 2005 to July 2013
Nigel Lockyer, September 2013 to the present

Fermilab continues to participate in the work at the Large Hadron Collider (LHC); it serves as a Tier 1 site in the Worldwide LHC Computing Grid.

DOE’s Fermi National Accelerator Laboratory(US) campus .

DOE’s Fermi National Accelerator Laboratory(US)/MINERvA Reidar Hahn.

DOE’s Fermi National Accelerator Laboratory(US) DAMIC | Fermilab Cosmic Physics Center.

DOE’s Fermi National Accelerator Laboratory(US) Muon g-2 studio. As muons race around a ring at the Muon g-2 studio, their spin axes twirl, reflecting the influence of unseen particles..

DOE’s Fermi National Accelerator Laboratory(US) Short-Baseline Near Detector under construction.

DOE’s Fermi National Accelerator Laboratory(US) Mu2e solenoid

Dark Energy Camera [DECam] built at DOE’s Fermi National Accelerator Laboratory(US).

Fermi National Accelerator Laboratory DUNE/LBNF experiment (US) Argon tank at Sanford Underground Research Facility(US)

DOE’s Fermi National Accelerator Laboratory (US) MicrobooNE

[caption id="attachment_155068" align="alignnone" width="632"] FNAL MicroBooNE’s time projection chamber

FNAL Don Lincoln.[/caption]

DOE’s Fermi National Accelerator Laboratory(US)/MINOS.

DOE’s Fermi National Accelerator Laboratory(US) Cryomodule Testing Facility.

DOE’s Fermi National Accelerator Laboratory(US) MINOS Far Detector.

FNAL DUNE LBNF (US) from FNAL to SURF Lead, South Dakota, USA .

European Organization for Nuclear Research [Organisation européenne pour la recherche nucléaire] (CH) ProtoDune.

DOE’s Fermi National Accelerator Laboratory(US)/NOvA experiment map .

DOE’s Fermi National Accelerator Laboratory(US) NOvA Near Detector at Batavia IL, USA .

DOE’s Fermi National Accelerator Laboratory(US) ICARUS.

DOE’s Fermi National Accelerator Laboratory(US) Holometer.

DOE’s Fermi National Accelerator Laboratory(US) LArIAT.

DOE’s Fermi National Accelerator Laboratory(US) ICEBERG particle detector.

From University of Rochester (US): “Rochester researchers join national initiative to advance quantum science”

From University of Rochester (US)

July 30, 2021

Peter Iglinski
585.273.4726
peter.iglinski@rochester.edu

The US Department of Energy has awarded a major grant to University of Rochester researchers, led by chemistry professor Todd Krauss (above), as part of an initiative to advance quantum science and technology. The researchers will address a principal challenge in quantum science: quantum states of matter are stable only at temperatures far colder than ever recorded on Earth. If stability can be achieved at room temperature, the benefits of quantum applications can be realized on a broader scale. Credit: J. Adam Fenster/University of Rochester photo.

Department of Energy grant recognizes the University’s long history of quantum research.

Todd Krauss, chair of the Department of Chemistry at the University of Rochester, and his fellow researchers are joining a $73 million initiative, funded by the Department of Energy (US), to advance quantum science and technology. Krauss’s project, “Understanding coherence in light‐matter interfaces for quantum science,” is one of 29 projects intended to help scientists better understand and to harness the “quantum world” in order to eventually benefit people and society.

“It’s exciting to see the University recognized for its work in the emerging field of quantum information science,” says Krauss.

The University has a long history in quantum science, dating back to physicist Leonard Mandel—considered a pioneer in quantum optics—in the 1960s. And Krauss says he and his colleagues are now building on the work of Mandel and other giants at Rochester, as well as leveraging the talents of the University’s current crop of quantum researchers.

Quantum science “the next technological revolution”

“Quantum science represents the next technological revolution and frontier in the Information Age, and America stands at the forefront,” said Secretary of Energy Jennifer M. Granholm as part of the DOE’s announcement of the funding. “At DOE, we’re investing in the fundamental research, led by universities and our National Labs, that will enhance our resiliency in the face of growing cyber threats and climate disasters, paving the path to a cleaner, more secure future.”

One of the principle challenges in this line of research, explains Krauss, is that quantum states of matter are typically stable only at temperatures below 10 degrees Kelvin; that’s roughly –441 degrees Fahrenheit. By comparison, the coldest recorded temperature on Earth was –128.6 at Russia’s Vostok station in Antarctica in 1983. If stability can be achieved at room temperature, then the benefits of quantum applications can be realized on a broader scale.

Faster computers, better sensors, more secure systems

More robust quantum states could yield exponentially faster computers, extremely responsive chemical or biological sensors, as well as more secure communication systems, an area that Krauss’s project is focused on. “In quantum state communications, it will be possible to know when someone else is monitoring your messaging,” says Krauss.

Krauss is being awarded $1.95 million over three years for his project on light-matter interfaces. Basically, says Krauss, “we’re sticking colloidal nanoparticles into optical cavities in order to interact the nanoparticles with the quantum-light of the cavity.” The work will be divided among four researchers:

>Krauss will focus on materials synthesis, characterization and spectroscopy.
>Nick Vamivakas, a professor of quantum optics and quantum physics at the University of Rochester’s Institute of Optics, will work on cavity fabrication and quantum optics measurements.
>Pengfei Huo, assistant professor of chemistry at the University of Rochester, will be the theorist of the group and will provide critical modeling of experiments.
.Steven Cundiff, professor of physics at the University of Michigan (US), will take state-of-the-art, nonlinear, ultrafast spectroscopic measurements.

“We are excited to be taking the field of quantum optics in completely new and uncharted directions with our studies of the quantum optics of nanoparticles,” says Krauss.

See the full article here .

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U Rochester

The University of Rochester (US) is a private research university in Rochester, New York. The university grants undergraduate and graduate degrees, including doctoral and professional degrees.

The University of Rochester (US) enrolls approximately 6,800 undergraduates and 5,000 graduate students. Its 158 buildings house over 200 academic majors. According to the National Science Foundation (US), Rochester spent $370 million on research and development in 2018, ranking it 68th in the nation. The university is the 7th largest employer in the Finger lakes region of New York.

The College of Arts, Sciences, and Engineering is home to departments and divisions of note. The Institute of Optics was founded in 1929 through a grant from Eastman Kodak and Bausch and Lomb as the first educational program in the US devoted exclusively to optics and awards approximately half of all optics degrees nationwide and is widely regarded as the premier optics program in the nation and among the best in the world. The Departments of Political Science and Economics have made a significant and consistent impact on positivist social science since the 1960s and historically rank in the top 5 in their fields. The Department of Chemistry is noted for its contributions to synthetic organic chemistry, including the first lab based synthesis of morphine. The Rossell Hope Robbins Library serves as the university’s resource for Old and Middle English texts and expertise. The university is also home to Rochester’s Laboratory for Laser Energetics, a Department of Energy (US) supported national laboratory.

University of Rochester(US) Laboratory for Laser Energetics.

The University of Rochester’s Eastman School of Music (US) ranks first among undergraduate music schools in the U.S. The Sibley Music Library at Eastman is the largest academic music library in North America and holds the third largest collection in the United States.

In its history university alumni and faculty have earned 13 Nobel Prizes; 13 Pulitzer Prizes; 45 Grammy Awards; 20 Guggenheim Awards; 5 National Academy of Sciences; 4 National Academy of Engineering; 3 Rhodes Scholarships; 3 National Academy of Inventors; and 1 National Academy of Inventors Hall of Fame.

History

Early history

The University of Rochester traces its origins to The First Baptist Church of Hamilton (New York) which was founded in 1796. The church established the Baptist Education Society of the State of New York later renamed the Hamilton Literary and Theological Institution in 1817. This institution gave birth to both Colgate University(US) and the University of Rochester. Its function was to train clergy in the Baptist tradition. When it aspired to grant higher degrees it created a collegiate division separate from the theological division.

The collegiate division was granted a charter by the State of New York in 1846 after which its name was changed to Madison University. John Wilder and the Baptist Education Society urged that the new university be moved to Rochester, New York. However, legal action prevented the move. In response, dissenting faculty, students, and trustees defected and departed for Rochester, where they sought a new charter for a new university.

Madison University was eventually renamed as Colgate University (US).

Founding

Asahel C. Kendrick- professor of Greek- was among the faculty that departed Madison University for Rochester. Kendrick served as acting president while a national search was conducted. He reprised this role until 1853 when Martin Brewer Anderson of the Newton Theological Seminary in Massachusetts was selected to fill the inaugural posting.

The University of Rochester’s new charter was awarded by the Regents of the State of New York on January 31, 1850. The charter stipulated that the university have $100,000 in endowment within five years upon which the charter would be reaffirmed. An initial gift of $10,000 was pledged by John Wilder which helped catalyze significant gifts from individuals and institutions.

Classes began that November with approximately 60 students enrolled including 28 transfers from Madison. From 1850 to 1862 the university was housed in the old United States Hotel in downtown Rochester on Buffalo Street near Elizabeth Street- today West Main Street near the I-490 overpass. On a February 1851 visit Ralph Waldo Emerson said of the university:

“They had bought a hotel, once a railroad terminus depot, for $8,500, turned the dining room into a chapel by putting up a pulpit on one side, made the barroom into a Pythologian Society’s Hall, & the chambers into Recitation rooms, Libraries, & professors’ apartments, all for $700 a year. They had brought an omnibus load of professors down from Madison bag and baggage… called in a painter and sent him up the ladder to paint the title “University of Rochester” on the wall, and they had runners on the road to catch students. And they are confident of graduating a class of ten by the time green peas are ripe.

For the next 10 years the college expanded its scope and secured its future through an expanding endowment; student body; and faculty. In parallel a gift of 8 acres of farmland from local businessman and Congressman Azariah Boody secured the first campus of the university upon which Anderson Hall was constructed and dedicated in 1862. Over the next sixty years this Prince Street Campus grew by a further 17 acres and was developed to include fraternities houses; dormitories; and academic buildings including Anderson Hall; Sibley Library; Eastman and Carnegie Laboratories the Memorial Art Gallery and Cutler Union.

Twentieth century

Coeducation

The first female students were admitted in 1900- the result of an effort led by Susan B. Anthony and Helen Barrett Montgomery. During the 1890s a number of women took classes and labs at the university as “visitors” but were not officially enrolled nor were their records included in the college register. President David Jayne Hill allowed the first woman- Helen E. Wilkinson- to enroll as a normal student although she was not allowed to matriculate or to pursue a degree. Thirty-three women enrolled among the first class in 1900 and Ella S. Wilcoxen was the first to receive a degree in 1901. The first female member of the faculty was Elizabeth Denio who retired as Professor Emeritus in 1917. Male students moved to River Campus upon its completion in 1930 while the female students remained on the Prince Street campus until 1955.

Expansion

Major growth occurred under the leadership of Benjamin Rush Rhees over his 1900-1935 tenure. During this period George Eastman became a major donor giving more than $50 million to the university during his life. Under the patronage of Eastman the Eastman School of Music (US) was created in 1921. In 1925 at the behest of the General Education Board and with significant support for John D. Rockefeller George Eastman and Henry A. Strong’s family medical and dental schools were created. The university award its first Ph.D that same year.

During World War II Rochester was one of 131 colleges and universities nationally that took part in the V-12 Navy College Training Program which offered students a path to a Navy commission. In 1942, the university was invited to join the Association of American Universities(US) as an affiliate member and it was made a full member by 1944. Between 1946 and 1947 in infamous uranium experiments researchers at the university injected uranium-234 and uranium-235 into six people to study how much uranium their kidneys could tolerate before becoming damaged.

In 1955 the separate colleges for men and women were merged into The College on the River Campus. In 1958 three new schools were created in engineering; business administration and education. The Graduate School of Management was named after William E. Simon- former Secretary of the Treasury in 1986. He committed significant funds to the school because of his belief in the school’s free market philosophy and grounding in economic analysis.

Financial decline and name change controversy

Following the princely gifts given throughout his life George Eastman left the entirety of his estate to the university after his death by suicide. The total of these gifts surpassed $100 million before inflation and as such Rochester enjoyed a privileged position amongst the most well endowed universities. During the expansion years between 1936 and 1976 the University of Rochester’s financial position ranked third, near Harvard University’s(US) endowment and the University of Texas (US) System’s Permanent University Fund. Due to a decline in the value of large investments and a lack of portfolio diversity the university’s place dropped to the top 25 by the end of the 1980s. At the same time the preeminence of the city of Rochester’s major employers began to decline.

In response the University commissioned a study to determine if the name of the institution should be changed to “Eastman University” or “Eastman Rochester University”. The study concluded a name change could be beneficial because the use of a place name in the title led respondents to incorrectly believe it was a public university, and because the name “Rochester” connoted a “cold and distant outpost.” Reports of the latter conclusion led to controversy and criticism in the Rochester community. Ultimately, the name “University of Rochester” was retained.

Renaissance Plan

In 1995 university president Thomas H. Jackson announced the launch of a “Renaissance Plan” for The College that reduced enrollment from 4,500 to 3,600 creating a more selective admissions process. The plan also revised the undergraduate curriculum significantly creating the current system with only one required course and only a few distribution requirements known as clusters. Part of this plan called for the end of graduate doctoral studies in chemical engineering; comparative literature; linguistics; and mathematics the last of which was met by national outcry. The plan was largely scrapped and mathematics exists as a graduate course of study to this day.

Twenty-first century

Meliora Challenge

Shortly after taking office university president Joel Seligman commenced the private phase of the “Meliora Challenge”- a $1.2 billion capital campaign- in 2005. The campaign reached its goal in 2015- a year before the campaign was slated to conclude. In 2016, the university announced the Meliora Challenge had exceeded its goal and surpassed $1.36 billion. These funds were allocated to support over 100 new endowed faculty positions and nearly 400 new scholarships.

The Mangelsdorf Years

On December 17, 2018 the University of Rochester announced that Sarah C. Mangelsdorf would succeed Richard Feldman as President of the University. Her term started in July 2019 with a formal inauguration following in October during Meliora Weekend. Mangelsdorf is the first woman to serve as President of the University and the first person with a degree in psychology to be appointed to Rochester’s highest office.

In 2019 students from China mobilized by the Chinese Students and Scholars Association (CSSA) defaced murals in the University’s access tunnels which had expressed support for the 2019 Hong Kong Protests, condemned the oppression of the Uighurs, and advocated for Taiwanese independence. The act was widely seen as a continuation of overseas censorship of Chinese issues. In response a large group of students recreated the original murals. There have also been calls for Chinese government run CSSA to be banned from campus.

Research

Rochester is a member of the Association of American Universities (US) and is classified among “R1: Doctoral Universities – Very High Research Activity”. Rochester had a research expenditure of $370 million in 2018. In 2008 Rochester ranked 44th nationally in research spending but this ranking has declined gradually to 68 in 2018. Some of the major research centers include the Laboratory for Laser Energetics, a laser-based nuclear fusion facility, and the extensive research facilities at the University of Rochester Medical Center. Recently the university has also engaged in a series of new initiatives to expand its programs in biomedical engineering and optics including the construction of the new $37 million Robert B. Goergen Hall for Biomedical Engineering and Optics on the River Campus. Other new research initiatives include a cancer stem cell program and a Clinical and Translational Sciences Institute. UR also has the ninth highest technology revenue among U.S. higher education institutions with $46 million being paid for commercial rights to university technology and research in 2009. Notable patents include Zoloft and Gardasil. WeBWorK, a web-based system for checking homework and providing immediate feedback for students was developed by University of Rochester professors Gage and Pizer. The system is now in use at over 800 universities and colleges as well as several secondary and primary schools. Rochester scientists work in diverse areas. For example, physicists developed a technique for etching metal surfaces such as platinum; titanium; and brass with powerful lasers enabling self-cleaning surfaces that repel water droplets and will not rust if tilted at a 4 degree angle; and medical researchers are exploring how brains rid themselves of toxic waste during sleep.

From Niels Bohr Institute [Niels Bohr Institutet] (DK): “New invention keeps qubits of light stable at room temperature”

From Niels Bohr Institute [Niels Bohr Institutet] (DK)

at

University of Copenhagen [Københavns Universitet] [UCPH] (DK)

17 June 2021

Eugene Simon Polzik, Professor
The Niels Bohr Institute
University of Copenhagen
+45 23 38 20 45
polzik@nbi.ku.dk

Ida Eriksen, Journalist
Faculty of Science
University of Copenhagen
+4593516002
ier@science.ku.dk

QUANTUM RESEARCH-Researchers from University of Copenhagen have developed a new technique that keeps quantum bits of light stable at room temperature instead of only working at -270 degrees. Their discovery saves power and money and is a breakthrough in quantum research.

Photo: Eugene Simon Polzik.

As almost all our private information is digitalized, it is increasingly important that we find ways to protect our data and ourselves from being hacked. Quantum Cryptography is the researchers’ answer to this problem, and more specifically a certain kind of qubit – consisting of single photons: particles of light.

Single photons or qubits of light as they are also called are extremely difficult to hack. However, in order for these qubits of light to be stable and work properly they need to be stored at temperatures close to absolute zero – that is minus 270 C – something that requires huge amounts of power and resources.

Yet in a recently published study [Nature Communications], researchers from University of Copenhagen, demonstrate a new way to store these qubits at room temperature for a hundred times longer than ever shown before.

“We have developed a special coating for our memory chips that helps the quantum bits of light to be identical and stable while being in room temperature. In addition, our new method enables us to store the qubits for a much longer time, which is milliseconds instead of microseconds – something that has not been possible before. We are really excited about it,” says Eugene Simon Polzik, professor in quantum optics at the Niels Bohr Institute.

The special coating of the memory chips makes it much easier to store the qubits of light without big freezers, which are troublesome to operate and require a lot of power. Therefore, the new invention will be cheaper and more compatible with the demands of the industry in the future.

“The advantage of storing these qubits at room temperature is that it does not require liquid helium or complex laser-systems for cooling. Also it is a much more simple technology that can be implemented more easily in a future quantum internet,” says Karsten Dideriksen, a UCPH-PhD on the project.

Photo of the memory chip, protected in a glasscell. Credit: Eugene Simon Polzik.

A special coating keeps the qubits stable

Normally warm temperatures disturb the energy of each quantum bit of light.

“In our memory chips, thousands of atoms are flying around emitting photons also known as qubits of light. When the atoms are exposed to heat, they start moving faster and collide with one another and with the walls of the chip. This leads them to emit photons that are very different from each other. But we need them to be exactly the same in order to use them for safe communication in the future,” explains Eugene Polzik and adds:

“That is why we have developed a method that protects the atomic memory with the special coating for the inside of the memory chips. The coating consists of paraffin that has a wax like structure and it works by softening the collision of the atoms, making the emitted photons or qubits identical and stable. Also we used special filters to make sure that only identical photons were extracted from the memory chips”.

Even though the new discovery is a breakthrough in quantum research it stills needs more work.

“Right now we produce the qubits of light at a low rate – one photon per second, while cooled systems can produce millions in the same amount of time. But we believe there are important advantages to this new technology and that we can overcome this challenge in time,” Eugene concludes.

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Niels Bohr Institutet (DK) is a research institute of the Københavns Universitet [UCPH] (DK). The research of the institute spans astronomy, geophysics, nanotechnology, particle physics, quantum mechanics and biophysics.

The Institute was founded in 1921, as the Institute for Theoretical Physics of the Københavns Universitet [UCPH] (DK), by the Danish theoretical physicist Niels Bohr, who had been on the staff of the University of Copenhagen since 1914, and who had been lobbying for its creation since his appointment as professor in 1916. On the 80th anniversary of Niels Bohr’s birth – October 7, 1965 – the Institute officially became The Niels Bohr Institutet (DK). Much of its original funding came from the charitable foundation of the Carlsberg brewery, and later from the Rockefeller Foundation.

During the 1920s, and 1930s, the Institute was the center of the developing disciplines of atomic physics and quantum physics. Physicists from across Europe (and sometimes further abroad) often visited the Institute to confer with Bohr on new theories and discoveries. The Copenhagen interpretation of quantum mechanics is named after work done at the Institute during this time.

On January 1, 1993 the institute was fused with the Astronomic Observatory, the Ørsted Laboratory and the Geophysical Institute. The new resulting institute retained the name Niels Bohr Institutet (DK)).

Københavns Universitet (UCPH) (DK) is the oldest university and research institution in Denmark. Founded in 1479 as a studium generale, it is the second oldest institution for higher education in Scandinavia after Uppsala University [ Uppsala universitet] (SE) (1477). The university has 23,473 undergraduate students, 17,398 postgraduate students, 2,968 doctoral students and over 9,000 employees. The university has four campuses located in and around Copenhagen, with the headquarters located in central Copenhagen. Most courses are taught in Danish; however, many courses are also offered in English and a few in German. The university has several thousands of foreign students, about half of whom come from Nordic countries.

The university is a member of the International Alliance of Research Universities (IARU), along with University of Cambridge (UK), Yale University (US), The Australian National University (AU), and University of California-Berkeley (US), amongst others. The 2016 Academic Ranking of World Universities ranks the University of Copenhagen as the best university in Scandinavia and 30th in the world, the 2016-2017 Times Higher Education World University Rankings as 120th in the world, and the 2016-2017 QS World University Rankings as 68th in the world. The university has had 9 alumni become Nobel laureates and has produced one Turing Award recipient.

From MIT: “Transforming quantum computing’s promise into practice” William Oliver

From MIT News

January 19, 2021
Daniel Ackerman

Electrical engineer William Oliver develops technology to enable reliable quantum computing at scale.

MIT electrical engineer William D. Oliver develops the fundamental technology to enable reliable quantum computers at scale.
Credit: Adam Glanzman.

It was music that sparked William Oliver’s lifelong passion for computers.

Growing up in the Finger Lakes region of New York, he was an avid keyboard player. “But I got into music school on voice,” says Oliver, “because it was a little bit easier.”

But once in school, first at State University of New York at Fredonia then the University of Rochester, he hardly shied away from a challenge. “I was studying sound recording technology, which led me to digital signal processing,” explains Oliver. “And that led me to computers.” Twenty-five years later, he’s still stuck on them.

Oliver, a recently tenured associate professor in MIT’s Department of Electrical Engineering and Computer Science, is building a new class of computer — the quantum computer — with the potential to radically improve how we process information and simulate complex systems. Quantum computing is still in its early days, and Oliver aims to help usher the field out of the laboratory and into the real world. “Our mission is to build the fundamental technologies that are necessary to scale up quantum computing,” he says.

Coast to coast and back again

Oliver’s first stop at MIT was as a master’s student in the Media Lab with adviser Tod Machover. Their interactive Brain Opera project paired Oliver’s love for both music and computing. Oliver orchestrated users’ voices with a computer-generated “angelic arpeggiation of strings and a chorus.” The project was installed at the Haus der Musik museum in Vienna. “It was a fantastic master’s project. I really loved it,” says Oliver. “But the question was ‘okay, what do I do next?’”

Eager for a new challenge, Oliver chose to explore more fundamental research. “I found quantum mechanics to be really puzzling and interesting,” says Oliver. So he traveled to Stanford University to earn a PhD studying quantum optics using free electrons. “I feel very fortunate that I could do those experiments, which have almost no practical application, but that allowed me to think really deeply about quantum mechanics,” he says.

Oliver’s timing was fortunate too. He was delving into quantum mechanics just as the field of quantum computing was emerging. A classical computer, like the one you’re using to read this story, stores information in binary bits, each of which holds a value of 0 or 1. In contrast, a quantum computer stores information in qubits, each of which can hold a 0, 1, or any simultaneous combination of 0 and 1, thanks to a quantum mechanical phenomenon called superposition. That means quantum computers can process information far faster than classical computers, in some cases completing tasks in minutes where a classical computer would take millennia — at least in theory. When Oliver was completing his PhD, quantum computing was a field in its infancy, more idea than reality. But Oliver grasped the potential of quantum computing, so he returned to MIT to help it grow.

The qubit quandary

Quantum computers are frustratingly inconsistent. That’s in part because those qubit superposition states are fragile. In a process called decoherence, qubits can err and lose their quantum information from the slightest disturbance or material defect. In 2003, Oliver took a staff position at MIT’s Lincoln Laboratory to help solve problems like decoherence. His goal, with colleagues Terry Orlando, Leonya Levitov, and Seth Lloyd, was to engineer reliable quantum computing systems that can be scaled up for practical use. “Quantum computing is transitioning from scientific curiosity to technical reality,” says Oliver. “We know that it works at small scale. And we’re now trying to increase the size of the systems so we can do problems that are actually meaningful.”

Even background levels of radiation can trigger decoherence in mere milliseconds. In a recent Nature paper, Oliver and his colleagues, including professor of physics Joe Formaggio, described this problem and proposed ways to shelter qubits from damaging radiation, like shielding them with lead.

He is quick to emphasize the role of collaboration in solving these complex challenges. “Engineering these quantum systems into useful, larger scale machines is going to require almost every department at the Institute,” says Oliver. In his own research, he builds qubits from electrical circuits in aluminum that are supercooled to just a smidge warmer than absolute zero. At that temperature, the system loses electrical resistance and can be used as an anharmonic oscillator that stores quantum information. Engineering such an intricate system to reliably process information means “we need to bring in a lot of people with their own talents,” says Oliver.

“For example, materials scientists will have a lot to say about the materials and the defects on the surfaces,” he adds. “Electrical engineers will have something to say about how to fabricate and control the qubits. Computer scientists and applied mathematicians will have something to say about the algorithms. Chemists and biologists know the hard problems to solve. And so on.” When he first joined Lincoln Laboratory, Oliver says just two Lincoln staff were focused on quantum technologies. That number now exceeds 100.

In 2015, Oliver founded the Engineering Quantum Systems (EQuS) group to focus specifically on superconducting qubit technology. He is also a Lincoln Laboratory Fellow, director of MIT’s Center for Quantum Engineering, and associate director of the Research Laboratory of Electronics.

A quantum future

Oliver envisions a steadily growing role for quantum computing. Already, Google has demonstrated that for a particular task, a 53-qubit quantum computer can far outpace even the world’s largest supercomputer, which features quadrillions of transistors. “That was like the flight at Kitty Hawk,” says Oliver. “It got off the ground.”

Google quantum computer.

In the near-term, Oliver thinks quantum and classical computers could work as partners. The classical machine would churn through an algorithm, dispatching specific calculations for the quantum computer to run before its qubits decohere. In the longer term, Oliver says that error-correcting codes could enable quantum computers to function indefinitely, even as some individual components remain faulty. “And that’s when quantum computers will basically be universal,” says Oliver. “They’ll be able to run any quantum algorithm at large scale.” That could enable vastly improved simulations of complex systems in fields like molecular biology, quantum chemistry, and climatology.

Oliver will continue to push quantum computing toward that reality. “There are real accomplishments that have been happening,” he says. “At the same time, on the theoretical side, there are real problems we could solve if we just had a quantum computer big enough.” While focused on his mission to scale up quantum computing, Oliver hasn’t lost his passion for music. Although, he says he rarely sings these days: “Only in the shower.”

See the full article here .

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The mission of MIT is to advance knowledge and educate students in science, technology, and other areas of scholarship that will best serve the nation and the world in the twenty-first century. We seek to develop in each member of the MIT community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.

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From phys.org: “Metasurface enabled quantum edge detection”

From phys.org

December 29, 2020
Thamarasee Jeewandara

The schematics of a metasurface enabled quantum edge detection. (A) The metasurface is designed to perform edge detection for a preferred linear polarization. |V〉, i.e., polarization state is orthogonal to the analyzer. The dashed light red line stands for the electrical path. The question mark means that polarization selection of idler photons of the heralding arm is unknown. If the Schrödinger’s cat is illuminated by unknown linear polarization photons from the polarization entangled source, the image would be a superposition of a regular “solid cat” and an edge-enhanced “outlined cat.” (B) The switch state ON or OFF of the heralding arm. When the idler photons of the heralding arm are projected to |H〉, it indicates the switch OFF state and leads to a solid cat captured. While the heralded photons are projected to |V〉, an edge-enhanced outlined cat is obtained with the switch ON state. (C and D) The calculated and experimental results of a solid cat, respectively. (E and F) The calculated and experimental results of the edge-enhanced outlined cat, respectively. Credit: Science Advances.

Metasurfaces provide unique platforms to realize exotic phenomena including negative refraction, achromatic focusing, and electromagnetic cloaking due to the engineered dielectric or metallic architectures. The intersection of metasurfaces and quantum optics can lead to significant opportunities that remain to be explored. In a new report now published on Science Advances, Junxiao Zhou, Shikai Liu and a research team in quantum information, nano-optoelectronic devices and computer engineering in China and the U.S. proposed and demonstrated a polarization-entangled photon source. They used the source to switch the optical edge mode in an imaging system to ON or OFF states based on a highly dielectric metasurface. The experiment enriched the fields of quantum optics and metamaterials as a promising direction toward quantum edge detection and image processing with a remarkable signal-to-noise ratio.

Combining quantum entanglement and edge detection

Photonic metasurfaces are two-dimensional (2-D) ultrathin arrays of engineered metallic or dielectric structures that can facilitate electromagnetic field manipulation of the local phase, amplitude and polarization. Researchers generally develop such capabilities for a variety of applications in classical optics. Quantum entanglement is essential in quantum optics for many applications including quantum cryptography, teleportation, superresolving metrology and quantum imaging. Recent efforts show a trend to combine the metasurface with entangled photons for potential applications in quantum optics. Edge detection is another factor that contributes to image processing to define the boundaries between regions in an image. It is a basic tool in computer vision to pre-process automations in medical imaging and forms a critical component of autonomous vehicles. Metasurface-enabled edge detection can be used in quantum optics to offer possibilities of remote-controlled image processing and cryptography. In this work, Zhou et al. therefore realized a polarization-entangled photon source and high-efficiency metasurface enabled switchable optical edge detection method. The combined strategy showed a high signal-to-noise (SNR) ratio at the same photon flux level (the number of photons per second per unit area).

Experimental setup and sample characterization. (A) Experimental setup of metasurface enabled quantum edge detection. BDM, broadband dielectric mirror; PBS, polarization beam splitter; DM, dichromatic mirror; FC, fiber coupler; BPF, band-pass filter; ICCD, intensified charge coupled device. By pumping a nonlinear crystal (type II phase-matched bulk PPKTP crystal) with a 405-nm laser, pairs of orthogonally polarized photons with 810-nm wavelength are generated through the spontaneously parametric down-conversion process. The blue (red) light path presents the 405-nm (810 nm) light. Edge detection switch is on the heralding arm. An edge detection imaging system is on the imaging arm. (B) Photograph of the partial metasurface sample. Scale bar, 4 mm. (C) Polariscopic analysis characterized by crossed linear polarizers of the sample area marked in 2a. The blue bars indicate the orientation of rotated nanostructures in one period, which represents the Pancharatnam-Berry phase induced by the laser writing dielectric metasurface. Scale bar, 50 μm. (D) The scanning electron microscopy image of the sample area marked in (C). Scale bar, 1 μm. Photo credit: Junxiao Zhou, University of California, San Diego. Credit: Science Advances [above].

Using the “Schrödinger’s cat” concept

Zhou et al. used the Schrödinger’s cat concept to illustrate the expected performance of the switchable quantum edge detection scheme. They reviewed the basic principle of edge detection based on classical continuous wave (CW) light-illumination. In the experimental setup, the edge detection imaging arm was independent of the entangled source and the heralding arm, as well as the coincidence measurement components. When the incident photons achieved a horizontal polarization state, the beam of illuminated light passed through a cat-shaped aperture and an engineered metasurface to separate into a left- and right-handed overlapped polarized image with a horizontal shift. The overlapped components then passed through a horizontally oriented analyzer to form a ‘solid cat’ image. If, however, the incident photons were vertically polarized, the overlapped components recombined to a linear polarized component that is completely blocked by the analyzer to only form an outline of a cat. The researchers therefore used polarization-entangled photons as a source of illumination to develop quantum switchable edge detection in this way.

The experimental setup and polarization-entangled photon pairs

Characterizations of the entangled source. (A) Coincidence counts as a function of the HWP angle θ2 at one output port in 2 s. The red (blue) color of count data and interference corresponds to horizontal (diagonal) projection bases. The solid lines are sinusoidal fits to the data, error bars are estimated by assuming Poisson photon statistics in photon counting. Error bars are obtained from multiple measurements. (B and C) The real and imaginary parts of the reconstructed density matrix ρ of the two-photon states, respectively. Credit: Science Advances [above].

The researchers generated polarization entangled photons using a spontaneous parametric down-conversion process in a 20-mm-long type II phase-matched periodically poled potassium titanyl phosphate (KTiOPO4/PPKTP) crystal embedded in a Sagnac interferometer. They set the temperature of the crystal to 17 degrees Celsius and used two broadband dielectric mirrors and a dual-wavelength polarization beam splitter to form the self-stable Sagnac interferometer. They then used a continuous wave single-frequency diode laser at 405 nm to generate the pump beam focused by a pair of lenses with optimized focal lengths to attain a beam waist approximating 40 microns at the center of the crystal. To balance the power in the clockwise and counter-clockwise-directions, Zhou et al. used a quarter-wave plate (QWP) and a half-wave plate (HWP) in front to the Sagnac loop.

Using a dual-wavelength polarization beam splitter, they separated the down-converted photon pairs pumped by two counter-propagating beams, to send one into the imaging arm and the other to heralding arms, respectively. Zhou et al. also designed the metasurface employed in the setup using the Pancharatnam-Berry phase and fabricated it by scanning a femtosecond pulse laser within a silica slab. Then using scanning electron microscopy, they observed self-assembled nanostructures in the silica slab and showed their origin under intense laser irradiation to generate the metasurface. The team briefly described the quantum state preparation for the polarization entangled degenerate photon pairs generated from the Signac loop. They used the Bell state (the simplest example of nonseparable quantum entanglement) for this work by adjusting the experimental setup. Zhou et al. quantified the entanglement quality of the two-photon state using quantum tomography and reconstructed two-photon density matrix measurements.

The switchable edge detection demonstration. (A to D) The metasurface sample orientation, which is aligned with the xy plane. The inset yellow arrows indicate the phase gradient direction of the metasurface. (E to H) The images of the whole object comprising the separated LCP and RCP components, which is the OFF state of the edge detection mode. (I to L) The images reveal edges along different directions, which is the ON state of the edge detection mode. Photo credit: Junxiao Zhou, University of California, San Diego. Credit: Science Advances [above].

Quantum-entanglement enabled quantum edge detection

After confirming the quality of generated polarization-entangled photon pairs, they demonstrated switchable quantum edge detection. To accomplish this, they prepared the photons in horizontal or vertical linear polarizations states using the setup and coupled the photons into the fiber and sent them to the edge detection image system to capture the final alternative image via an intensified charge-coupled device camera (ICCD). For instance, Zhou et al. obtained two overlapped images with a tiny shift, where the shift direction aligned with the phase gradient direction of the metasurface. When they increased the period of the metasurface structure, they decreased the shift between the two overlapped images to achieve high-resolution edge detection. The quantum edge detection scheme had another advantage due to its high signal-to-noise (SNR) ratio, where the team could significantly reduce the ambient noise in the setup, where noise only accumulated in a very short timeframe. By contrast, in classical optics, the noise would continue to accumulate. As proof of concept, they acquired an edge image with remarkable SNR for improved entanglement-enabled experimental quantum edge detection.

Outlook

In this way, Junxiao Zhou, Shikai Liu and colleagues combined quantum entanglement-enabled quantum edge detection using a metasurface filter combined with a polarization-entangled source. The metasurfaces provided ultrathin and lightweight optical elements with precisely engineered phase profiles to obtain a variety of functions to form a more compact and integrated system. The setup will assist the conception of security applications including image encryption and steganography. The method also offers an appealing signal-to-noise (SNR) ratio suited for a variety of photon-hungry imaging and sensing applications in biomedicine, including tracking enzymatic reactions and observing living organisms or photosensitive cells.

More information:

Flat optics with designer metasurfaces
Nature Materials

Experimental quantum teleportation
Nature

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From The Optical Society via phys.org: “Researchers demonstrate nondestructive mid-infrared imaging using entangled photons”

From The Optical Society

via

phys.org

December 10, 2020

Researchers used entangled photons to increase the penetration depth of OCT for scattering materials. They demonstrated the technique by analyzing two alumina ceramic stacks containing laser-milled microchannels. The mid-infrared illumination allowed the researchers to capture depth information and to create a full 3D reconstruction of the channel structures (pictured). Credit: Aron Vanselow and Sven Ramelow, Humboldt-Universität zu Berlin.

Researchers have shown that entangled photons can be used to improve the penetration depth of optical coherence tomography (OCT) in highly scattering materials. The method represents a way to perform OCT with mid-infrared wavelengths and could be useful for non-destructive testing and analysis of materials such as ceramics and paint samples.

OCT is a nondestructive imaging method that provides detailed 3-D images of subsurface structures. OCT is typically performed using visible or near-infrared wavelengths because light sources and detectors for these wavelengths are readily available. However, these wavelengths don’t penetrate very deeply into highly scattering or very porous materials.

In Optica, The Optical Society’s (OSA) journal for high-impact research, Aron Vanselow and colleagues from Humboldt-Universität zu Berlin (DE), together with collaborators at the Research Center for Non-Destructive Testing GmbH in Austria, demonstrate a proof-of-concept experiment for mid-infrared OCT based on ultra-broadband entangled photon pairs. They show that this approach can produce high quality 2-D and 3-D images of highly scattering samples using a relatively compact, straightforward optical setup.

“Our method eliminates the need for broadband mid-infrared sources or detectors, which have made it challenging to develop practical OCT systems that work at these wavelengths,” said Vanselow. “It represents one of the first real-world applications in which entangled photons are competitive with conventional technology.”

The technique could be useful for many applications including analyzing the complex paint layers used on airplanes and cars or monitoring the coatings used on pharmaceuticals. It can also provide detailed 3-D images that would be useful for art conservation.

Tapping into quantum mechanics

When photons are entangled, they behave as if they can instantly affect each other. This quantum mechanical phenomenon is essential to many quantum technology applications under development, such as quantum sensing, quantum communications or quantum computing.

For this technique, the researchers developed and patented a nonlinear crystal that creates broadband photon pairs with very different wavelengths. One of the photons has a wavelength that can be easily detected with standard equipment while the other photon is in the mid-infrared range, making it difficult to detect. When the hard-to-detect photons illuminate a sample, they change the signal in a way that can be measured using only the easy-to-detect photons.

“Our technique makes it easy to acquire useful measurements at what is a traditionally hard-to-handle wavelength range due to technology challenges,” said Sven Ramelow, who conceived and guided the research. “Moreover, the lasers and optics we used are not complex and are also more compact, robust and cost-effective than those used in current mid-infrared OCT systems.”

Imaging with less light

To demonstrate the technique, the researchers first confirmed that the performance of their optical setup matched theoretical predictions. They found that they could use six orders of magnitude less light to achieve the same signal-to-noise ratio as the few conventional mid-infrared OCT systems that have been recently developed.

“We were positively surprised that we did not see any noise in the measurements beyond the intrinsic quantum noise of the light itself,” said Ramelow. “This also explained why we can achieve a good signal-to-noise ratio with so little light.”

The researchers tested their setup on a range of real-world samples, including highly scattering paint samples. They also analyzed two 900-micron thick alumina ceramic stacks containing laser-milled microchannels. The mid-infrared illumination allowed the researchers to capture depth information and to create a full 3-D reconstruction of the channel structures. The pores in alumina ceramics make this material useful for drug testing and DNA detection but also highly scattering at the wavelengths traditionally used for OCT.

The researchers have already begun to engage with partners from industry and other research institutes to develop a compact OCT sensor head and full system for a pilot commercial application.

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The Optical Society (OSA) is a professional association of individuals and companies with an interest in optics and photonics. It publishes journals, and organizes conferences and exhibitions. In 2019 it had about 22,000 members in more than 100 different countries, including some 300 companies