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  • richardmitnick 1:55 pm on September 25, 2020 Permalink | Reply
    Tags: "Columbia Leads Effort to Build a Quantum Simulator", By the end of phase two teams are expected to deliver solutions that impact societal needs at scale., , NSF Convergence Accelerator award, Quantum Computing, The Columbia team will develop hardware and software concepts to build a versatile quantum simulator based on ordered arrays of atoms., The funding will enable Columbia University to develop the concept for a quantum simulator that can help tackle real-world challenges., The team includes Columbia University; Brookhaven National Laboratory; City University of New York; Flatiron Institute; and industry partners from Atom Computing; QuEra; IBM; and Bloomberg., The team includes experts in atomic physics; photonics; electronics; and software as well as future users of the platform.   

    From Columbia University: “Columbia Leads Effort to Build a Quantum Simulator” 

    Columbia U bloc

    From Columbia University

    September 24, 2020
    Carla Cantor

    The project is supported by an NSF Convergence Accelerator award that funds team-based, multidisciplinary initiatives addressing challenges of national importance.

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    Columbia is one of 11 institutions nationwide to receive a Phase One National Science Foundation Convergence Accelerator award for quantum technology. The program is designed to foster multidisciplinary, cross-sector research in emerging areas of critical societal importance. Credit: NSF

    Columbia is one of 11 institutions nationwide to receive a Phase One Convergence Accelerator award for quantum technology. These awards support the National Quantum Initiative Act passed in 2018 to accelerate the development of quantum science and information technology applications. The U.S. Congress has authorized up to $1.2 billion of research funding for quantum information science, including computing.

    The hope of building a quantum computer with the potential to resolve seemingly intractable problems across many different industries and applications relies on controlling microscopic quantum systems with higher and higher precision in order to put them to work for computing tasks.

    With this grant, the Columbia team will develop hardware and software concepts to build a versatile quantum simulator based on ordered arrays of atoms. The group will store quantum information in individual atoms and program them to perform quantum simulations. Besides developing the device, the plan is to make it accessible to a broad user base via cloud-computing.

    Quantum technologies—simulators and computers specifically—have the potential to revolutionize the 21st century, from improved national defense systems to drug discovery to more powerful sensors and communication networks.

    But the field still needs to make major advances before quantum computing can surpass existing tools to process information and live up to its promise.

    A multidisciplinary research team led by Columbia University is in a position to bring quantum technology out of the lab into real-world applications. The team has received a $1 million National Science Foundation (NSF) Convergence Accelerator award to build a quantum simulator, a device that can solve problems that are difficult to simulate on classical computers. The project includes physicists, engineers, computer scientists, mathematicians, and educators from academia, national labs, and industry.

    “This funding will enable us to develop the concept for a quantum simulator that can help tackle real-world challenges,” said Sebastian Will, assistant professor of physics at Columbia and principal investigator on the project. “For this we brought a diverse team together that includes experts in atomic physics, photonics, electronics, and software, as well as future users of the platform.”

    The National Science Foundation launched its Convergence Accelerator program, a major new research investment unique for NSF and the federal government, in 2019 to help quickly transition research and discovery aligning with NSF’s “Big Ideas” into practice. In 2020, the NSF continues to invest in two transformative research areas of national importance: quantum technology and artificial intelligence.

    Over the next nine months, the 2020 cohort Convergence Accelerator teams will work to develop their initial concept, identify new team members, and participate in a curriculum focusing on design, team science, pitch preparation, and presentation coaching. After developing a prototype, the teams will participate in a pitch competition and proposal evaluation. Teams selected for phase two will be eligible for additional funding: up to $5 million over 24 months.

    By the end of phase two, teams are expected to deliver solutions that impact societal needs at scale.

    “The quantum technology and AI-driven data and model-sharing topics were chosen based on community input and identified federal research and development priorities,” said Douglas Maughan, head of the NSF Convergence Accelerator program. “This is the program’s second cohort, and we are excited for these teams to use convergence research and innovation-centric fundamentals to accelerate solutions that have a positive societal impact.”

    The simulator project team includes collaborators from Columbia University, principal investigator Sebastian Will, co-principal investigators Alex Gaeta and Nanfang Yu, and others; Brookhaven National Lab, co-principal investigators Layla Hormozi and Gabriella Carini, and others; City University of New York; Flatiron Institute; and industry partners from Atom Computing, QuEra, IBM, and Bloomberg.

    See the full article here .

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    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.

     
  • richardmitnick 1:59 pm on September 16, 2020 Permalink | Reply
    Tags: "IBM promises 1000-qubit quantum computer—a milestone—by 2023", , , IBM is already preparing a jumbo liquid-helium refrigerator or cryostat to hold a quantum computer with 1 million qubits., Quantum Computing,   

    From Science: “IBM promises 1000-qubit quantum computer—a milestone—by 2023” 

    From Science

    Sep. 15, 2020
    Adrian Cho

    1
    IBM researchers have already installed the mounting hardware for a jumbo cryostat big enough to hold a quantum computer with 1 million qubits.
    Credit: Connie Zhou/IBM.

    For 20 years scientists and engineers have been saying that “someday” they’ll build a full-fledged quantum computer able to perform useful calculations that would overwhelm any conventional supercomputer. But current machines contain just a few dozen quantum bits, or qubits, too few to do anything dazzling. Today, IBM made its aspirations more concrete by publicly announcing a “road map” for the development of its quantum computers, including the ambitious goal of building one containing 1000 qubits by 2023. IBM’s current largest quantum computer, revealed this month, contains 65 qubits.

    “We’re very excited,” says Prineha Narang, co-founder and chief technology officer of Aliro Quantum, a startup that specializes in code that helps higher level software efficiently run on different quantum computers. “We didn’t know the specific milestones and numbers that they’ve announced,” she says. The plan includes building intermediate-size machines of 127 and 433 qubits in 2021 and 2022, respectively, and envisions following up with a million-qubit machine at some unspecified date. Dario Gil, IBM’s director of research, says he is confident his team can keep to the schedule. “A road map is more than a plan and a PowerPoint presentation,” he says. “It’s execution.”

    IBM is not the only company with a road map to build a full-fledged quantum computer—a machine that would take advantage of the strange rules of quantum mechanics to breeze through certain computations that just overwhelm conventional computers. At least in terms of public relations, IBM has been playing catch-up to Google, which 1 year ago grabbed headlines when the company announced its researchers had used their 53-qubit quantum computer to solve a particular abstract problem that they claimed would overwhelm any conventional computer—reaching a milestone known as quantum supremacy.

    1
    Judging by the cover of Nature, 24 October 2019 marked a turning point in the decades-long effort to harness the strange laws of quantum mechanics in the service of computing.

    Google 54-qubit Sycamore superconducting processor quantum computer.

    Google has its own plan to build a million-qubit quantum computer within 10 years, as Hartmut Neven, who leads Google’s quantum computing effort, explained in an April interview, although he declined to reveal a specific timeline for advances.

    IBM’s declared timeline comes with an obvious risk that everyone will know if it misses its milestones. But the company decided to reveal its plans so that its clients and collaborators would know what to expect. Dozens of quantum-computing startup companies use IBM’s current machines to develop their own software products, and knowing IBM’s milestones should help developers better tailor their efforts to the hardware, Gil says.

    One company joining those efforts is Q-CTRL, which develops software to optimize the control and performance of the individual qubits. The IBM announcement shows venture capitalists the company is serious about developing the challenging technology, says Michael Biercuk, founder and CEO of Q-CTRL. “It’s relevant to convincing investors that this large hardware manufacturer is pushing hard on this and investing significant resources,” he says.

    A 1000-qubit machine is a particularly important milestone in the development of a full-fledged quantum computer, researchers say. Such a machine would still be 1000 times too small to fulfill quantum computing’s full potential—such as breaking current internet encryption schemes—but it would big enough to spot and correct the myriad errors that ordinarily plague the finicky quantum bits.

    A bit in an ordinary computer is an electrical switch that can be set to either zero or one. In contrast, a qubit is a quantum device—in IBM’s and Google’s machines, each is a tiny circuit of superconducting metal chilled to nearly absolute zero—that can be set to zero, one, or, thanks to the strange rules of quantum mechanics, zero and one at the same time. But the slightest interaction with the environment tends to distort those delicate two-ways-at-once states, so researchers have developed error-correction protocols to spread information ordinarily encoded in a single physical qubit to many of them in a way that the state of that “logical qubit” can be maintained indefinitely.

    With their planned 1121-qubit machine, IBM researchers would be able to maintain a handful of logical qubits and make them interact, says Jay Gambetta, a physicist who leads IBM’s quantum computing efforts. That’s exactly what will be required to start to make a full-fledged quantum computer with thousands of logical qubits. Such a machine would mark an “inflection point” in which researchers’ focus would switch from beating down the error rate in the individual qubits to optimizing the architecture and performance of the entire system, Gambetta says.

    IBM is already preparing a jumbo liquid-helium refrigerator, or cryostat, to hold a quantum computer with 1 million qubits. The IBM road map doesn’t specify when such a machine could be built. But if company researchers really can build a 1000-qubit computer in the next 2 years, that ultimate goal will sound far less fantastical than it does now.

    See the full article here .


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  • richardmitnick 8:37 am on August 28, 2020 Permalink | Reply
    Tags: "Quantum Innovations Achieved Using Alkaline-Earth Atoms", , , , Quantum Computing,   

    From Caltech: “Quantum Innovations Achieved Using Alkaline-Earth Atoms” 

    Caltech Logo

    From Caltech

    August 27, 2020
    Whitney Clavin
    (626) 395‑1944
    wclavin@caltech.edu

    Caltech entangled qubits

    In the quest to develop quantum computers, physicists have taken several different paths. For instance, Google recently reported that their prototype quantum computer might have made a specific calculation faster than a classical computer. Those efforts relied on a strategy that involves superconducting materials, which are materials that, when chilled to ultracold temperatures, conduct electricity with zero resistance. Other quantum computing strategies involve arrays of charged or neutral atoms.

    Now, a team of quantum physicists at Caltech has made strides in work that uses a more complex class of neutral atoms called the alkaline-earth atoms, which reside in the second column of the periodic table. These atoms, which include magnesium, calcium, and strontium, have two electrons in their outer regions, or shells. Previously, researchers who experimented with neutral atoms had focused on elements located in the first column of the periodic table, which have just one electron in their outer shells.

    In a paper published in the journal Nature Physics, the researchers demonstrate that they can use individually controlled alkaline-earth atoms to achieve a hallmark of quantum computing: entanglement. This seemingly paradoxical phenomenon occurs when two atoms remain intimately connected even when separated by vast distances. Entanglement is essential to quantum computers because it enables the computers’ internal “switches,” known as qubits, to be correlated with each other and to encode an exponential amount of information.

    “Essentially, we are breaking a two-qubit entanglement record for one of the three leading quantum science platforms: individual neutral atoms,” says Manuel Endres, an assistant professor of physics and leader of the Caltech team. Endres is also a member of one of three new quantum research institutes established by the National Science Foundation’s (NSF’s) Quantum Leap Challenges Institutes program, and a member of one of five new Department of Energy quantum science centers.

    National Quantum Initiative.

    “We are opening up a new tool box for quantum computers and other applications,” says Ivaylo Madjarov, a Caltech graduate student and lead author of the new study. “With alkaline-earth atoms, we have more opportunities for manipulating systems and new opportunities for precise manipulation and readout of the system.”

    To achieve their goal, the researchers turned to optical tweezers, which are basically laser beams that can maneuver individual atoms. The team previously used the same technology to develop a new design for optical atomic clocks. In the new study, the tweezers were used to persuade two strontium atoms within an array of atoms to become entangled.

    “We had previously demonstrated the first control of individual alkaline-earth atoms. In the present work, we have added a mechanism to generate entanglement between the atoms, based on highly excited Rydberg states, in which atoms separated by many microns feel large forces from each other,” says Jacob Covey, a postdoctoral scholar at Caltech. “The unique properties of the alkaline-earth atoms offer new ways to improve and characterize the Rydberg-interaction mechanism.”

    What is more, the researchers were able to create the entangled state with a higher degree of accuracy than had been previously achieved through the use of neutral atoms, and with an accuracy on par with other quantum computing platforms.

    In the future, the researchers hope to expand their ability to control individual qubits, and they plan to further investigate methods to entangle three or more atoms.

    “The endgame is to reach a very high level of entanglement and programmability for many atoms in order to be able to perform calculations that are intractable by a classical computer,” says Endres. “Our system is also suited to investigate how such many-atom entanglement could improve the stability of atomic clocks.”

    The study, published in the August issue of Nature Physics and titled High-fidelity entanglement and detection of alkaline-earth Rydberg atoms, was funded by NSF, the Sloan Foundation, F. Blum, Caltech, the Gordon and Betty Moore Foundation, and the Larson SURF Fellowship. Other authors include, at Caltech: graduate student Adam L. Shaw; Joonhee Choi, IQIM Postdoctoral Scholar in Physics; Anant Kale, laboratory assistant; Alexandre Cooper, former postdoctoral scholar in physics; and Hannes Pichler, former Moore Postdoctoral Scholar in Theoretical Physics; and Vladimir Schkolnik and Jason R. Williams of the Jet Propulsion Laboratory (JPL), which is managed by Caltech for NASA.

    See the full article here .


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    The California Institute of Technology (commonly referred to as Caltech) is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. “The mission of the California Institute of Technology is to expand human knowledge and benefit society through research integrated with education. We investigate the most challenging, fundamental problems in science and technology in a singularly collegial, interdisciplinary atmosphere, while educating outstanding students to become creative members of society.”

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  • richardmitnick 7:46 am on August 15, 2020 Permalink | Reply
    Tags: "UChicago scientists discover way to make quantum states last 10000 times longer", By precisely tuning this field the scientists could rapidly rotate the electron spins and allow the system to “tune out” the rest of the noise., Quantum Computing, , Simple innovation expected to open multiple new avenues for quantum science., The team applied an additional continuous alternating magnetic field., This small change allowed the system to stay coherent up to 22 milliseconds- four orders of magnitude higher than without the modification.,   

    From University of Chicago: “UChicago scientists discover way to make quantum states last 10,000 times longer” 

    U Chicago bloc

    From University of Chicago

    Aug 13, 2020
    Louise Lerner

    Simple innovation expected to open multiple new avenues for quantum science.

    1
    Postdoctoral researcher Kevin Miao works on quantum research at the University of Chicago’s Pritzker School of Molecular Engineering. Photo by David Awschalom.

    If we can harness it, quantum technology promises fantastic new possibilities. But first, scientists need to coax quantum systems to stay yoked for longer than a few millionths of a second.

    A team of scientists at the University of Chicago’s Pritzker School of Molecular Engineering announced the discovery of a simple modification that allows quantum systems to stay operational—or “coherent”—10,000 times longer than before. Though the scientists tested their technique on a particular class of quantum systems called solid-state qubits, they think it should be applicable to many other kinds of quantum systems and could thus revolutionize quantum communication, computing and sensing.

    The study was published Aug. 13 in Science.

    “This breakthrough lays the groundwork for exciting new avenues of research in quantum science,” said study lead author David Awschalom, the Liew Family Professor in Molecular Engineering, senior scientist at Argonne National Laboratory and director of the Chicago Quantum Exchange. “The broad applicability of this discovery, coupled with a remarkably simple implementation, allows this robust coherence to impact many aspects of quantum engineering. It enables new research opportunities previously thought impractical.”

    Down at the level of atoms, the world operates according to the rules of quantum mechanics—very different from what we see around us in our daily lives. These different rules could translate into technology like virtually unhackable networks or extremely powerful computers; the U.S. Department of Energy released a blueprint for the future quantum internet in an event at UChicago on July 23. But fundamental engineering challenges remain: Quantum states need an extremely quiet, stable space to operate, as they are easily disturbed by background noise coming from vibrations, temperature changes or stray electromagnetic fields.

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    From left: Scientists Kevin Miao, Chris Anderson and Alexandre Bourassa work on quantum research in the Awschalom lab at the University of Chicago’s Pritzker School of Molecular Engineering. Photo by David Awschalom.

    Thus, scientists try to find ways to keep the system coherent as long as possible. One common approach is physically isolating the system from the noisy surroundings, but this can be unwieldy and complex. Another technique involves making all of the materials as pure as possible, which can be costly. The scientists at UChicago took a different tack.

    “With this approach, we don’t try to eliminate noise in the surroundings; instead, we “trick” the system into thinking it doesn’t experience the noise,” said postdoctoral researcher Kevin Miao, the first author of the paper.

    In tandem with the usual electromagnetic pulses used to control quantum systems, the team applied an additional continuous alternating magnetic field. By precisely tuning this field, the scientists could rapidly rotate the electron spins and allow the system to “tune out” the rest of the noise.

    “To get a sense of the principle, it’s like sitting on a merry-go-round with people yelling all around you,” Miao explained. “When the ride is still, you can hear them perfectly, but if you’re rapidly spinning, the noise blurs into a background.”

    This small change allowed the system to stay coherent up to 22 milliseconds, four orders of magnitude higher than without the modification—and far longer than any previously reported electron spin system. (For comparison, a blink of an eye takes about 350 milliseconds). The system is able to almost completely tune out some forms of temperature fluctuations, physical vibrations, and electromagnetic noise, all of which usually destroy quantum coherence.

    The simple fix could unlock discoveries in virtually every area of quantum technology, the scientists said.

    “This approach creates a pathway to scalability,” said Awschalom. “It should make storing quantum information in electron spin practical. Extended storage times will enable more complex operations in quantum computers and allow quantum information transmitted from spin-based devices to travel longer distances in networks.”

    Though their tests were run in a solid-state quantum system using silicon carbide, the scientists believe the technique should have similar effects in other types of quantum systems, such as superconducting quantum bits and molecular quantum systems. This level of versatility is unusual for such an engineering breakthrough.

    “There are a lot of candidates for quantum technology that were pushed aside because they couldn’t maintain quantum coherence for long periods of time,” Miao said. “Those could be re-evaluated now that we have this way to massively improve coherence.

    “The best part is, it’s incredibly easy to do,” he added. “The science behind it is intricate, but the logistics of adding an alternating magnetic field are very straightforward.”

    Other UChicago scientists on the study were graduate student Joseph Blanton, postdoctoral researcher Chris Anderson, graduate students Alexandre Bourassa and Alex Crook, and Argonne scientist Gary Wolfowicz. Hiroshi Abe and Takeshi Ohshima with Japan’s National Institutes for Quantum and Radiological Science and Technology were also co-authors. The team used resources at the Pritzker Nanofabrication Facility. The team is working with the Polsky Center for Entrepreneurship and Innovation to commercialize the discovery.

    See the full article here .

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    U Chicago Campus

    An intellectual destination

    One of the world’s premier academic and research institutions, the University of Chicago has driven new ways of thinking since our 1890 founding. Today, UChicago is an intellectual destination that draws inspired scholars to our Hyde Park and international campuses, keeping UChicago at the nexus of ideas that challenge and change the world.

    The University of Chicago is an urban research university that has driven new ways of thinking since 1890. Our commitment to free and open inquiry draws inspired scholars to our global campuses, where ideas are born that challenge and change the world.

    We empower individuals to challenge conventional thinking in pursuit of original ideas. Students in the College develop critical, analytic, and writing skills in our rigorous, interdisciplinary core curriculum. Through graduate programs, students test their ideas with UChicago scholars, and become the next generation of leaders in academia, industry, nonprofits, and government.

    UChicago research has led to such breakthroughs as discovering the link between cancer and genetics, establishing revolutionary theories of economics, and developing tools to produce reliably excellent urban schooling. We generate new insights for the benefit of present and future generations with our national and affiliated laboratories: Argonne National Laboratory, Fermi National Accelerator Laboratory, and the Marine Biological Laboratory in Woods Hole, Massachusetts.

    The University of Chicago is enriched by the city we call home. In partnership with our neighbors, we invest in Chicago’s mid-South Side across such areas as health, education, economic growth, and the arts. Together with our medical center, we are the largest private employer on the South Side.

    In all we do, we are driven to dig deeper, push further, and ask bigger questions—and to leverage our knowledge to enrich all human life. Our diverse and creative students and alumni drive innovation, lead international conversations, and make masterpieces. Alumni and faculty, lecturers and postdocs go on to become Nobel laureates, CEOs, university presidents, attorneys general, literary giants, and astronauts.

     
  • richardmitnick 11:00 am on August 14, 2020 Permalink | Reply
    Tags: "Yale quantum researchers create an error-correcting cat", , , Quantum Computing, , Schrödinger’s cat, ,   

    From Yale University: “Yale quantum researchers create an error-correcting cat” 

    From Yale University

    August 12, 2020

    Media Contact
    Fred Mamoun
    fred.mamoun@yale.edu
    203-436-2643

    By Jim Shelton

    1
    (Illustration by Michael S. Helfenbein)

    Yale physicists have developed an error-correcting cat — a new device that combines the Schrödinger’s cat concept of superposition (a physical system existing in two states at once) with the ability to fix some of the trickiest errors in a quantum computation.

    It is Yale’s latest breakthrough in the effort to master and manipulate the physics necessary for a useful quantum computer: correcting the stream of errors that crop up among fragile bits of quantum information, called qubits, while performing a task.

    A new study reporting on the discovery appears in the journal Nature. The senior author is Michel Devoret, Yale’s F.W. Beinecke Professor of Applied Physics and Physics. The study’s co-first authors are Alexander Grimm, a former postdoctoral associate in Devoret’s lab who is now a tenure-track scientist at the Paul Scherrer Institute in Switzerland, and Nicholas Frattini, a graduate student in Devoret’s lab.

    Quantum computers have the potential to transform an array of industries, from pharmaceuticals to financial services, by enabling calculations that are orders of magnitude faster than today’s supercomputers.

    Yale — led by Devoret, Robert Schoelkopf, and Steven Girvin — continues to build upon two decades of groundbreaking quantum research. Yale’s approach to building a quantum computer is called “circuit QED” and employs particles of microwave light (photons) in a superconducting microwave resonator.

    In a traditional computer, information is encoded as either 0 or 1. The only errors that crop up during calculations are “bit-flips,” when a bit of information accidentally flips from 0 to 1 or vice versa. The way to correct it is by building in redundancy: using three “physical” bits of information to ensure one “effective” — or accurate — bit.

    In contrast, quantum information bits — qubits — are subject to both bit-flips and “phase-flips,” in which a qubit randomly flips between quantum superpositions (when two opposite states exist simultaneously).

    Until now, quantum researchers have tried to fix errors by adding greater redundancy, requiring an abundance of physical qubits for each effective qubit.

    Enter the cat qubit — named for Schrödinger’s cat, the famous paradox used to illustrate the concept of superposition.

    The idea is that a cat is placed in a sealed box with a radioactive source and a poison that will be triggered if an atom of the radioactive substance decays. The superposition theory of quantum physics suggests that until someone opens the box, the cat is both alive and dead, a superposition of states. Opening the box to observe the cat causes it to abruptly change its quantum state randomly, forcing it to be either alive or dead.

    “Our work flows from a new idea. Why not use a clever way to encode information in a single physical system so that one type of error is directly suppressed?” Devoret asked.

    Unlike the multiple physical qubits needed to maintain one effective qubit, a single cat qubit can prevent phase flips all by itself. The cat qubit encodes an effective qubit into superpositions of two states within a single electronic circuit — in this case a superconducting microwave resonator whose oscillations correspond to the two states of the cat qubit.

    “We achieve all of this by applying microwave frequency signals to a device that is not significantly more complicated than a traditional superconducting qubit,” Grimm said.

    The researchers said they are able to change their cat qubit from any one of its superposition states to any other superposition state, on command. In addition, the researchers developed a new way of reading out — or identifying — the information encoded into the qubit.

    “This makes the system we have developed a versatile new element that will hopefully find its use in many aspects of quantum computation with superconducting circuits,” Devoret said.

    Co-authors of the study are Girvin, Shruti Puri, Shantanu Mundhada, and Steven Touzard, all of Yale; Mazyar Mirrahimi of Inria Paris; and Shyam Shankar of the University of Texas-Austin.

    The United States Department of Defense, the United States Army Research Office, and the National Science Foundation funded the research.

    Related

    Physicists can predict the jumps of Schrödinger’s cat (and finally save it)
    In quantum computing, doubling down on Schrödinger’s cat

    See the full article here .

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    Yale University comprises three major academic components: Yale College (the undergraduate program), the Graduate School of Arts and Sciences, and the professional schools. In addition, Yale encompasses a wide array of centers and programs, libraries, museums, and administrative support offices. Approximately 11,250 students attend Yale.

     
  • richardmitnick 11:20 am on July 28, 2020 Permalink | Reply
    Tags: "Shining a light on the quantum world", , In the quantum world light is two things: both a wave and a small particle called a photon., , , , Quantum Computing, , Quantum light   

    From MIT News: “Shining a light on the quantum world” 

    MIT News

    From MIT News

    July 27, 2020
    Fernanda Ferreira | School of Science

    1
    MIT graduate student Nicholas Rivera (middle) and two students from Professor Ido Kaminer’s lab visit Masada National Park near the Dead Sea in Israel. Photo courtesy of the researchers.

    2
    Researchers at MIT and Israel’s Technion used a thin-film material composed of layers of gallium-arsenide and indium-gallium-arsenide, overlaid with a layer of graphene, as shown in this diagram, to produce strong interactions between light and particles that could someday enable highly tunable lasers orL EDs. Image courtesy of the researchers.

    3
    Front row, left to right: Ido Kaminer, Nicholas Rivera, and Bo Zhen. Back row, left to right: professors John Joannopoulos and Marin Soljačić. Photo courtesy of the researchers.

    With funding from MISTI, physicists at MIT and in Israel collaborate to improve understanding and use of quantum light.

    In the universe, there is the world we can see with the naked eye: trees, planes in the sky, dishes in the sink. But there are other worlds that reveal themselves with the help of a magnifying glass, telescope, or microscope. With these, we can see up into the universe or down into the smallest particles that make it up. The smallest of these is a world populated by particles smaller than an atom: the quantum world.

    Physicists who probe this world study how these subatomic particles interact with one another, often in ways not predicted by behavior at the atomic or molecular level. One such physicist is Nicholas Rivera, who studies light-matter interactions at the quantum level.

    Unfinished business

    In the quantum world, light is two things: both a wave and a small particle called a photon. “I was always fascinated with light, especially the quantum nature of light,” says Rivera, a Department of Physics graduate student in Professor Marin Soljačić’s group.

    According to Rivera, there is still a lot we don’t know about quantum light, and uncovering these unknowns may prove useful for a number of applications. “It’s connected to a lot of interesting problems,” says Rivera, such as how to make better quantum computers and lasers at new frequencies like ultraviolet and X-ray. It’s this dual nature of the work — with fundamental questions coupled with practical solutions — that attracted Rivera to his current area of research.

    Rivera joined Soljačić’s group in 2013, when he was an undergraduate at MIT. Since then his research has focused on how light and matter interact at the most elementary level, between quanta of light, also called photons, and electrons of matter. These interactions are governed by the laws of quantum electrodynamics and involve the emission of photons by electrons that hop up and down energy levels. This may sound simple, but it is surprisingly difficult because light and matter are operating on two different size scales, which often means these interactions are inefficient. One specific goal of Rivera’s work is to improve that efficiency.

    “The atom is this tiny thing, a 10th of a nanometer large,” says Rivera. But when light takes the form of a wave, its wavelengths are much larger than an atom. “The idea is that, because of this mismatch, many of the possible ways that an electron could release a photon are just too slow to be observable.” Rivera uses theory to figure out how light and matter could be manipulated to allow for new types of interactions and ways to intentionally change the quantum state of light.

    Inefficient interactions are often thought of as “forbidden” because, in normal circumstances, they would take billions of years to happen. “The forbidden light-matter interactions project is something we have been thinking about for many years, but we didn’t have a suitable material-system platform for it,” says Soljačić. In 2015, graphene plasmons arrived on the scene, and forbidden interactions could be explored.

    Graphene is an ultra-thin 2D material, and plasmons are another quantum-scale particle related to the oscillation of electrons. In these ultra-thin materials, light can be “shrunk” so that the wavelengths are closer to the scale of the electrons, making forbidden interactions possible.

    Rivera’s first paper on this topic [Science], published the summer after he graduated with his bachelor’s degree in 2016, was the start of his longstanding collaboration with Ido Kaminer, an assistant professor at the Technion-Israel Institute of Technology. But Rivera wasn’t done with light-matter interactions. “There were so many other directions that one could go with that work, and I really wanted the ability to probe all of them,” Rivera says, and he decided to stay in Soljačić’s group for his PhD.

    A natural match

    That first collaboration with Kaminer, who was then a postdoc in Soljačić’s group, was a pivotal moment in Rivera’s career as a physicist. “I was working on a different project with Marin, but then he invited me to his office with Ido and told me about the project that would become the 2016 paper,” says Rivera. According to Soljačić, putting Kaminer and Rivera together “was a natural match.”

    Kaminer moved to the Technion in 2018, which was when Rivera took his first trip to Haifa, Israel, with funds provided by MISTI-Israel, a program within the MIT International Science and Technology Initiatives (MISTI). There, he gave a seminar and met with students and professors. “That visit seeded some projects that we’re still working on today,” says Rivera, such as a project where vacuum forces were used to generate X-ray photons. [physicsworld].

    With the help of lasers and optical materials, it’s relatively easy to generate photons of visible light, but making X-ray photons is much harder. “We don’t have lasers the same way we do for visible light, and we don’t have as many materials to manipulate X-rays,” says Rivera. The search for new strategies for generating X-ray photons is important, Rivera says, because these photons can help scientists explore physics at the atomic scale.

    This past January, Rivera visited Israel for the third time. On these trips, “[we make] progress on the collaborations we have with the students, and also brainstorm new projects,” says Rivera. According to Kaminer, the in-person brainstorming is vital when coming up with new ideas. “Such creative ideas are, in the end, the most important part of our work as scientists,” Kaminer explains. During each visit, Rivera and Kaminer sketch out a research plan for the next six months to year, such as continuing to investigate new ways to control and generate quantum sources of X-ray photons.

    When investigating the theory of light-matter interactions, the potential applications are never far from Rivera’s mind. “We’re trying to think about applications that could potentially be realized next year and in the next five years, but even potentially further down the line.”

    For Rivera, being able to be in the same place as his collaborators is a major boon, and he doubts the continued collaboration with Kaminer would be as active if he hadn’t taken that first trip to Haifa in 2018. “And the hummus isn’t bad,” he jokes.

    When Soljačić introduced Rivera and Kaminer five years ago, neither expected that the collaboration would still be going strong. “It’s hard to anticipate what collaborations will be successful in the long term,” says Kaminer. “But more important than the collaboration is the friendship,” he adds.

    The deeper Rivera explores the quantum aspects of light-matter interactions, the more potential avenues of exploration open up. “It just keeps branching,” says Rivera. And he envisions himself continuing to visit Kaminer in Israel, no matter where his research takes him next. “It’s a lifelong collaboration at this point.”

    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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  • richardmitnick 8:06 am on July 28, 2020 Permalink | Reply
    Tags: "Quantum edge", , College of Engineering, , Quantum Computing,   

    From University of Washington College of Engineering: “Quantum edge” 

    From University of Washington

    College of Engineering

    7.28.20
    Sarah DeWeerdt

    “We see our role as not only the science and engineering research, but also workforce development – the training component. That’s what we do best.” – Jim Pfaendtner, ChemE Chair and UW Associate Vice Provost for Research Computing

    1

    In October 2019, Google scientists announced that they had achieved a long-awaited technological benchmark known as quantum supremacy: they had built a quantum computer capable of performing a calculation that a classical computer could not.

    Google quantum computer

    Google’s rivals, notably IBM, questioned this claim. “But we’re right on the cusp of this tipping point,” says Jim Pfaendtner, chemical engineering chair and Associate Vice Provost for Research Computing at the UW. “If it didn’t happen in October, it’s going to happen soon. And that will just begin to open up a whole world.”

    IBM iconic image of Quantum computer

    A classical computer uses strings of 0s and 1s – binary digits, or bits – to perform calculations. A quantum computer uses quantum bits, or qubits. These represent information in superposition, meaning in multiple states at the same time – such as a digit that is simultaneously 0 and 1. In theory, this gives quantum computers the ability to solve problems that would take too long for classical computers to solve: cracking fiendishly difficult codes, sifting through molecular formulas to identify materials that could be useful for clean energy applications and designing silver-bullet cancer drugs from scratch.

    Laying the groundwork

    The UW aims to be a scientific leader of the coming quantum age. Pfaendtner co-chairs the steering committee of QuantumX, a UW initiative to stimulate research and teaching on “quantum everything,” as Pfaendtner puts it: computing, information science, materials and so on.

    The University is also part of the Northwest Quantum Nexus (NQN), a partnership with Microsoft and the U.S. Department of Energy’s Pacific Northwest National Laboratory (PNNL). NQN launched in spring 2019 and aims to boost the region’s economy by attracting scientists, large-scale funding and scientific collaborations in quantum fields to the area.

    The UW’s strengths in photonics, materials science, physics and electrical and computer engineering give it an edge in pursuing quantum science. Resources such as the Washington Nanofabrication Facility also help, as does the College of Engineering’s strong commitment to interdisciplinary collaboration.

    To program a quantum computer, “You have to come up with entirely new ways of writing software,” Pfaendtner says. “And often that has to be done within the context of the material that it’s made out of. So it’s an interdisciplinary problem.”

    Mo Li, co-chair of the QuantumX steering committee and associate professor of electrical and computer engineering and physics, agrees. “My work definitely involves multidisciplinary collaboration,” he says. He is working on quantum transduction, or the transfer of information between different types of qubits.

    “All of these qubits have their pros and cons,” says Li. Some only work at temperatures close to absolute zero, others require very large devices, and so on. “In the future, comprehensive quantum systems probably will involve many [types of qubits].” Li’s task is to get them to talk to each other reliably and efficiently. Specifically, he’s developing a mechanical device to aid transduction between superconducting qubits that work at low temperatures and microwave frequencies and optical qubits that work at room temperature and use visible light.

    On the optical qubit side, Li is collaborating with Kai-Mei Fu, co-founder of the QuantumX steering committee and an associate professor of electrical and computer engineering and physics. Fu works with qubits that take the form of extremely tiny aberrations, called defects, in ultra-pure diamond crystals. These defects can store information and emit photons that can transmit quantum information, helping to ensure secure communications.

    The problem is that Fu’s defects only emit the right kind of photons about 3% of the time. Finding or designing a different defect that emits the right photons more reliably would require simulating countless quantum mechanical interactions inside the diamond crystal. “So ideally you’d be using a quantum computer to do this,” Fu says. “But we don’t have a quantum computer. If we did, then we’d have the material [that we need] already!”

    Fu laughs. “So it’s a little bit of a Catch-22 right now. But we’re making a lot of progress.”

    Expanding research and job training

    There’s lots of basic science to be done in quantum fields. Professor of materials science and engineering and physics Xiaodong Xu is searching for new materials and exploring their quantum properties. Two years ago, he and his team discovered a material that, just a few layers of atoms in thickness, functions as a magnetic semiconductor. Materials with such properties could one day revolutionize cloud computing by enabling data storage and processing in the same material – reducing the size and energy consumption of data centers while increasing their speed.

    “I think the exact material we discovered probably will not yet be useful in terms of daily life,” Xu says. It only works at extremely low temperatures and is not stable in ambient conditions. “But the principle we demonstrated can be useful.” In addition, this type of material can be used to create topological qubits, one option for building a quantum computer.

    With plenty of room for such theoretical explorations, the UW’s quantum science efforts have a practical and pragmatic side as well. “We see our role as not only the science and engineering research, but also workforce development – the training component,” Pfaendtner says. “That’s what we do best.” That means streamlining graduate education and beefing up undergraduate curriculum. Eventually, the goal is also to develop retraining programs, so that established electrical engineers and computer programmers can add quantum skills to their resumes.

    Exactly how all that will be rolled out as part of QuantumX and NQN is uncertain for now. You might say these nascent efforts are currently in a state of superposition. “Anything could happen,” Pfaendtner says.

    But he expects it to happen fast. “In three to five more years, we’ll be able to look back at this year and next year as the ones that were really key.”

    See the full article here .


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    About the U Washington College of Engineering

    Mission, Facts, and Stats

    Our mission is to develop outstanding engineers and ideas that change the world.

    Faculty:
    275 faculty (25.2% women)
    Achievements:

    128 NSF Young Investigator/Early Career Awards since 1984
    32 Sloan Foundation Research Awards
    2 MacArthur Foundation Fellows (2007 and 2011)

    A national leader in educating engineers, each year the College turns out new discoveries, inventions and top-flight graduates, all contributing to the strength of our economy and the vitality of our community.

    Engineering innovation

    Engineers drive the innovation economy and are vital to solving society’s most challenging problems. The College of Engineering is a key part of a world-class research university in a thriving hub of aerospace, biotechnology, global health and information technology innovation. Over 50% of UW startups in FY18 came from the College of Engineering.
    Commitment to diversity and access

    The College of Engineering is committed to developing and supporting a diverse student body and faculty that reflect and elevate the populations we serve. We are a national leader in women in engineering; 25.5% of our faculty are women compared to 17.4% nationally. We offer a robust set of diversity programs for students and faculty.
    Research and commercialization

    The University of Washington is an engine of economic growth, today ranked third in the nation for the number of startups launched each year, with 65 companies having been started in the last five years alone by UW students and faculty, or with technology developed here. The College of Engineering is a key contributor to these innovations, and engineering faculty, students or technology are behind half of all UW startups. In FY19, UW received $1.58 billion in total research awards from federal and nonfederal sources.

    u-washington-campus
    The University of Washington is one of the world’s preeminent public universities. Our impact on individuals, on our region, and on the world is profound — whether we are launching young people into a boundless future or confronting the grand challenges of our time through undaunted research and scholarship. Ranked number 10 in the world in Shanghai Jiao Tong University rankings and educating more than 54,000 students annually, our students and faculty work together to turn ideas into impact and in the process transform lives and our world. For more about our impact on the world, every day.
    So what defines us —the students, faculty and community members at the University of Washington? Above all, it’s our belief in possibility and our unshakable optimism. It’s a connection to others, both near and far. It’s a hunger that pushes us to tackle challenges and pursue progress. It’s the conviction that together we can create a world of good. Join us on the journey.

     
  • richardmitnick 4:49 pm on July 16, 2020 Permalink | Reply
    Tags: "New Quantum Information Speed Limits Depend on the Task at Hand", For the same quantum computer the speed limits are different for different tasks., , Quantum Computing, Unlike speed limits on the highway most speed limits in physics cannot be disobeyed., You can never go faster than the speed of light (in a vacuum).   

    From Joint Quantum Institute: “New Quantum Information Speed Limits Depend on the Task at Hand” 

    JQI bloc

    From Joint Quantum Institute

    July 13, 2020
    Dina Genkina

    1
    A new protocol for cutting and pasting quantum information first spreads the content of one quantum bit (blue dot) over a region (black circle). Then, it takes advantage of long-range interactions (blue streaks) to transfer the information. Finally, it collects the information at the target quantum bit (red dot). (Credit: Chi-Fang Chen/Caltech)

    Unlike speed limits on the highway, most speed limits in physics cannot be disobeyed. For example, no matter how little you care about getting a ticket, you can never go faster than the speed of light. Similarly stringent limits exist for information, too. The speed of light is still the ultimate speed limit, but depending on how information is stored and transmitted, there can be slower limits in practice.

    The story gets particularly subtle when the information is quantum. Quantum information is represented by qubits (the quantum version of ordinary bits), which can be stored in photons, atoms or any number of other systems governed by the rules of quantum physics. Figuring out how fast information can move from one qubit to another is not only interesting from a fundamental point of view; it’s also important for more practical purposes, like improving the designs of quantum computers and learning what their limitations might be.

    Now, a group of UMD researchers led by JQI Fellow Alexey Gorshkov—who is also a Fellow of the Joint Center for Quantum Information and Computer Science and a physicist at the National Institute of Standards and Technology—in collaboration with teams at the University of Colorado Boulder, Caltech, and the Colorado School of Mines, have found something surprising: the speed limit for quantum information can depend on the task at hand. They detail their results in a paper published July 13, 2020 in the journal Physical Review X and featured in Physics.

    Just as knowing the speed of light doesn’t automatically let us build rockets that can travel that fast, knowledge of the speed at which quantum information can travel doesn’t tell us how it can be done. But figuring out what sets these speed limits did allow the team to come up with new information transfer methods that approach the theoretical speed limit closer than ever before.

    “Figuring out the fastest way to move quantum information around will help us maximize the performance of future quantum computers,” says Minh Tran, a graduate student in physics at UMD and the lead author of the paper.

    One procedure subject to these new limits is like a quantum cut and paste: moving the information stored in one qubit to a different one far away. It’s a crucial task that can become a bottleneck as quantum computers get larger and larger. In quantum computers based on superconductors, like Google’s Sycamore [Nature], qubits only really talk to their next-door neighbors. Or, in physics-speak, their interactions are short-range. That means that once you cut a qubit, you’d have to go door to door, cutting and pasting it until you reach the target. The speed limit for this situation was found back in the 1970’s. It’s strict and consistent—it doesn’t ease up no matter how far the information travels.

    Things get more complicated—and more realistic for a lot of quantum computing platforms—when you start to consider long-range interactions: qubits that talk not only to the ones directly next to them, but also to neighbors several doors down. Quantum computers built with trapped ions, polar molecules, and Rydberg atoms all have these long-range interactions.

    Previous work has shown that in long-range interacting setups, there isn’t always a strict speed limit. Sometimes, the information can travel faster once it’s gone further away from its starting point, and other times its speed isn’t limited at all (except for the ultimate limit set by the speed of light). This depends on the dimensions of the quantum computer (if it’s a chain, a pancake, or a cube) as well as the strength of the long-range interaction (how loudly one qubit can talk to another many doors down).

    Finding regimes where these long-range interactions relax the information speed limits carries the promise of making quantum processing much faster. Gorshkov, Tran and their collaborators looked more closely at the regime where the speed limit is not strict—where information is allowed to travel faster as it gets further away from its origin. What they found was surprising: for some applications, the speed limit was indeed loose as previously discovered. But for others, the speed limit was just as strict as in the nearest neighbor case.

    This implies that for the same quantum computer the speed limits are different for different tasks. And even for the same task, such as quantum cut-and-paste, different rules can apply in different situations. If you cut-and-paste in the beginning of a computation, the speed limit is loose, and you can do it very quickly. But if you have to do it mid-computation, when the states of the qubits along the way aren’t known, a stricter speed limit applies.

    “The existence of different speed limits is cool fundamentally because it shows a separation between tasks that seemed very similar,” says Abhinav Deshpande, a graduate student in physics at UMD and one of the authors of the new paper.

    So far, few experimental realizations of quantum computers have been able to take advantage of long-range interactions. Nevertheless, the state of the art is improving rapidly, and these theoretical findings may soon play a crucial role in designing quantum computing architectures and choosing protocols that optimize their efficiency. “Once you get systems that are larger and more coherent,” says Gorshkov, “down the road, these insights will be even more applicable.”

    See the full article here .


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    JQI supported by Gordon and Betty Moore Foundation

    We are on the verge of a new technological revolution as the strange and unique properties of quantum physics become relevant and exploitable in the context of information science and technology.

    The Joint Quantum Institute (JQI) is pursuing that goal through the work of leading quantum scientists from the Department of Physics of the University of Maryland (UMD), the National Institute of Standards and Technology (NIST) and the Laboratory for Physical Sciences (LPS). Each institution brings to JQI major experimental and theoretical research programs that are dedicated to the goals of controlling and exploiting quantum systems.

     
  • richardmitnick 11:55 am on July 8, 2020 Permalink | Reply
    Tags: "Scaling up the quantum chip", , MIT engineers develop a hybrid process that connects photonics with “artificial atoms” to produce the largest quantum chip of its type., Quantum Computing, The accomplishment “marks a turning point” in the field of scalable quantum processors., The qubits in the new chip are artificial atoms made from defects in diamond., The researchers were able to connect 128 qubits on one platform- so a 128-qubit system — the largest integrated artificial atom-photonics chip yet., This is a proof of concept that solid-state qubit emitters are very scalable quantum technologies.   

    From MIT News: “Scaling up the quantum chip” 

    MIT News

    From MIT News

    July 8, 2020
    Becky Ham

    MIT engineers develop a hybrid process that connects photonics with “artificial atoms,” to produce the largest quantum chip of its type.

    1
    This graphic depicts a stylized rendering of the quantum photonic chip and its assembly process. The bottom half of the image shows a functioning quantum micro-chiplet (QMC), which emits single-photon pulses that are routed and manipulated on a photonic integrated circuit (PIC). The top half of the image shows how this chip is made: Diamond QMCs are fabricated separately and then transferred into the PIC.
    Credit: Noel H Wan

    MIT researchers have developed a process to manufacture and integrate “artificial atoms,” created by atomic-scale defects in microscopically thin slices of diamond, with photonic circuitry, producing the largest quantum chip of its type.

    The accomplishment “marks a turning point” in the field of scalable quantum processors, says Dirk Englund, an associate professor in MIT’s Department of Electrical Engineering and Computer Science. Millions of quantum processors will be needed to build quantum computers, and the new research demonstrates a viable way to scale up processor production, he and his colleagues note.

    Unlike classical computers, which process and store information using bits represented by either 0s and 1s, quantum computers operate using quantum bits, or qubits, which can represent 0, 1, or both at the same time. This strange property allows quantum computers to simultaneously perform multiple calculations, solving problems that would be intractable for classical computers.

    The qubits in the new chip are artificial atoms made from defects in diamond, which can be prodded with visible light and microwaves to emit photons that carry quantum information. The process, which Englund and his team describe today in Nature, is a hybrid approach, in which carefully selected “quantum micro chiplets” containing multiple diamond-based qubits are placed on an aluminum nitride photonic integrated circuit.

    “In the past 20 years of quantum engineering, it has been the ultimate vision to manufacture such artificial qubit systems at volumes comparable to integrated electronics,” Englund says. “Although there has been remarkable progress in this very active area of research, fabrication and materials complications have thus far yielded just two to three emitters per photonic system.”

    Using their hybrid method, Englund and colleagues were able to build a 128-qubit system — the largest integrated artificial atom-photonics chip yet.

    “It’s quite exciting in terms of the technology,” says Marko Lončar, the Tiantsai Lin Professor of Electrical Engineering at Harvard University, who was not involved in the study. “They were able to get stable emitters in a photonic platform while maintaining very nice quantum memories.”

    Other authors on the Nature paper include MIT researchers Noel H. Wan, Tsung-Ju Lu, Kevin C. Chen, Michael P. Walsh, Matthew E. Trusheim, Lorenzo De Santis, Eric A. Bersin, Isaac B. Harris, Sara L. Mouradian and Ian R. Christen; with Edward S. Bielejec at Sandia National Laboratories.

    Quality control for chiplets

    The artificial atoms in the chiplets consist of color centers in diamonds, defects in diamond’s carbon lattice where adjacent carbon atoms are missing, with their spaces either filled by a different element or left vacant. In the MIT chiplets, the replacement elements are germanium and silicon. Each center functions as an atom-like emitter whose spin states can form a qubit. The artificial atoms emit colored particles of light, or photons, that carry the quantum information represented by the qubit.

    Diamond color centers make good solid-state qubits, but “the bottleneck with this platform is actually building a system and device architecture that can scale to thousands and millions of qubits,” Wan explains. “Artificial atoms are in a solid crystal, and unwanted contamination can affect important quantum properties such as coherence times. Furthermore, variations within the crystal can cause the qubits to be different from one another, and that makes it difficult to scale these systems.”

    Instead of trying to build a large quantum chip entirely in diamond, the researchers decided to take a modular and hybrid approach. “We use semiconductor fabrication techniques to make these small chiplets of diamond, from which we select only the highest quality qubit modules,” says Wan. “Then we integrate those chiplets piece-by-piece into another chip that ‘wires’ the chiplets together into a larger device.”

    The integration takes place on a photonic integrated circuit, which is analogous to an electronic integrated circuit but uses photons rather than electrons to carry information. Photonics provides the underlying architecture to route and switch photons between modules in the circuit with low loss. The circuit platform is aluminum nitride, rather than the traditional silicon of some integrated circuits.

    Using this hybrid approach of photonic circuits and diamond chiplets, the researchers were able to connect 128 qubits on one platform. The qubits are stable and long-lived, and their emissions can be tuned within the circuit to produce spectrally indistinguishable photons, according to Wan and colleagues.

    A modular approach

    While the platform offers a scalable process to produce artificial atom-photonics chips, the next step will be to “turn it on,” so to speak, to test its processing skills.

    “This is a proof of concept that solid-state qubit emitters are very scalable quantum technologies,” says Wan. “In order to process quantum information, the next step would be to control these large numbers of qubits and also induce interactions between them.”

    The qubits in this type of chip design wouldn’t necessarily have to be these particular diamond color centers. Other chip designers might choose other types of diamond color centers, atomic defects in other semiconductor crystals like silicon carbide, certain semiconductor quantum dots, or rare-earth ions in crystals. “Because the integration technique is hybrid and modular, we can choose the best material suitable for each component, rather than relying on natural properties of only one material, thus allowing us to combine the best properties of each disparate material into one system,” says Lu.

    Finding a way to automate the process and demonstrate further integration with optoelectronic components such as modulators and detectors will be necessary to build even bigger chips necessary for modular quantum computers and multichannel quantum repeaters that transport qubits over long distances, the researchers say.

    See the full article here .


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    MIT Seal

    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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  • richardmitnick 10:20 am on June 4, 2020 Permalink | Reply
    Tags: "Quantum Leaps on the Horizon", , Paola Cappellaro PhD ’06 advances next-generation computing, Quantum Computing   

    From MIT Spectrum: “Quantum Leaps on the Horizon” 


    From MIT Spectrum

    Spring 2020
    Mark Wolverton

    1
    Paola Cappellaro experiments with a diamond chip containing qubits, shown at the center of this apparatus, seeking ways to address errors in quantum computing. Photo: Courtesy of Quantum Engineering Group

    Paola Cappellaro PhD ’06 advances next-generation computing

    “Quantum” is one of those buzzwords that shows up in everything from science fiction to business branding. But quantum computing—or, more specifically, quantum information science and engineering—is a real, cutting-edge discipline focused on developing systems that will leave today’s fastest supercomputers in the dust.

    In fact, it’s a whole ecosystem of technology based on quantum mechanics, a field of physics centered on how subatomic particles move and interact, according to Paola Cappellaro PhD ’06, an associate professor in the Department of Nuclear Science and Engineering (NSE). Cappellaro is at the forefront of MIT’s quantum computing research as leader of the Quantum Engineering Group in the Research Laboratory of Electronics.

    “In my group, we work not only on quantum computing but also on associated technologies,” Cappellaro says. “The common thread is quantum information science, how to manipulate, encode, and exploit information using quantum devices.”

    The technology is still in its infancy, but approaching computing from the vanguard of physics promises a sea change in how computers tackle huge mathematical challenges, such as breaking cryptographic codes, and simulate intricate systems, such as complex chemical reactions.

    More memory and power

    While conventional computers operate by processing bits of data consisting of zeros and ones, generally encoded in electronic form as on/off, quantum computing is based on principles that permit subatomic particles to be in different states simultaneously, enabling quantum bits, or “qubits,” to hold more information.

    In theory, a quantum computer should outmatch even the most advanced supercomputer—but so far, no one has quite figured out the best way to build one. That’s because there are many possible ways to create the qubits of data, all involving different physical systems and types of hardware. Also, qubits are delicate and subject to what physicists call “decoherence” or the collapse of their fragile quantum state at the slightest vibration or change in temperature.

    Another major challenge centers on addressing errors, which today’s computers handle through redundancy. “Instead of just encoding information in one bit, you can encode them in a certain number of bits and then you take a majority vote,” she says. This doesn’t work in the fuzzier realm of qubits, for a variety of reasons including that the disturbance caused by measurement (“wave-function collapse”) forbids checking the majority vote conditions.

    Cappellaro’s Quantum Engineering Group is using electron and nuclear spins to address this challenge. Their approach centers on a type of defect found within the crystal lattice of diamond, called a nitrogen-vacancy or N-V center, that could be harnessed to create qubits. “We came up with a way of characterizing the noise in our system and then came up with an efficient way of protecting it from errors,” she says. “What we hope is that … we can actually have a practical error correction system for today’s intermediate-scale quantum devices.”

    Collaborations at MIT

    Quantum computers are expected to be able to tackle the biggest of big data challenges, but the specific applications may depend on which systems prove most practical. “We’re still in the stage where we’re trying to pick the best technology,” Cappellaro says.

    Making such choices means exploring many different options, reflected in the broad range of researchers involved in quantum computing across the MIT School of Science and the MIT School of Engineering, as well as many groups at MIT Lincoln Laboratory. The MIT Stephen A. Schwarzman College of Computing is expected to better unite the Institute’s quantum computing efforts.

    “We have a long tradition in quantum computation,” Cappellaro observes. “But the Schwarzman College could position MIT even better to play a larger role both in the United States and on the world stage. It’s definitely an opportunity to be seized.”

    See the full article here .


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    MIT Spectrum connects friends and supporters of the Massachusetts Institute of Technology to MIT’s vision, impact, and exceptional community.

    MIT Seal

    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. Paths of discovery cross every day at MIT, propelling groundbreaking research and furthering personal development. Although it’s not always clear where a path will lead, MIT aims high, working to ensure that humanity’s collective trajectory is pointed toward a brighter future.

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