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  • richardmitnick 3:14 pm on June 9, 2016 Permalink | Reply
    Tags: , , DRAGON at TRIUMF, ,   

    From Ohio U: “Probing Red Giants with a DRAGON” 

    Ohio U bloc

    Ohio University

    June 9, 2016
    Jean Andrews

    Scientists study stars called red giants to better understand processes such as nuclear fusion—the dominant source of energy for stars in the universe. L to R: Dr. Carl Brune, Dr. Annika Lennarz, a TRIUMF postdoctoral researcher, OHIO doctoral students Som Nath Paneru, and Rikam Giri

    Dr. Carl Brune, Professor of Physics & Astronomy and member of the Institute of Nuclear and Particle Physics (INPP), traveled recently to TRIUMF, Canada’s national lab for nuclear and particle physics, located in Vancouver. With him were his doctoral students Rekam Giri and Som Nath Paneru. The purpose of their visit was to use the DRAGON, a specialized instrument which measures the fusion of helium and carbon — an important process that occurs in red giant stars.


    “These measurements will help us to understand where the oxygen in the universe comes from and help to confirm that our models for how stars evolve and produce elements are correct, “ Brune says. “The DRAGON is an ideal instrument for this type of experiment.”

    The DRAGON apparatus is used to study nuclear reactions important in astrophysics. By recreating the nuclear reactions that occur inside exploding stars, researchers are better able to understand reactions that produce the chemical elements and energy generation in stars. DRAGON is an acronym for Detector of Recoils And Gammas Of Nuclear reactions.

    How Stars Evolve into Red Giants

    Brune is particularly interested in energy processes taking place within red giants. These are stars in the last stages of stellar evolution that have exhausted the supply of hydrogen in their cores and have begun thermonuclear fusion of hydrogen in a shell surrounding the core.

    “Most stars, including our sun, are burning hydrogen in the cores,” Brune explains. “Once the hydrogen in the core is exhausted, the stars begin to burn helium and become red giants. They expand in diameter and their outer edge is lower in temperature, giving them a reddish-orange hue. Helium is burned by two fusion reactions within a red giant: the fusion of three helium nuclei into carbon and the fusion of helium with carbon to form oxygen.”

    The fusion of helium with carbon at this stage is thought to be the main source of oxygen in the universe – even the oxygen on the earth.

    The DRAGON instrument at TRIUMF is a recoil separator that is used to detect the oxygen nuclei produced. A carbon beam was used to bombard a helium target. The oxygen nuclei produced by fusion are separated from the carbon beam by the DRAGON instrument and counted.

    Brune, Giri, and Paneru are part of a team of nuclear physicists that includes researchers from TRIUMF, the Colorado School of Mines, and Michigan State University. The group convened the week of May 3-10 to run the experiment using the DRAGON.

    See the full article here .

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    Ohio U campus

    n 1786, 11 men gathered at the Bunch of Grapes Tavern in Boston to propose development of the area north of the Ohio River and west of the Allegheny Mountains known then as the Ohio Country. Led by Manasseh Cutler and Rufus Putnam, the Ohio Company petitioned Congress to take action on the proposed settlement. The eventual outcome was the enactment of the Northwest Ordinance of 1787, which provided for settlement and government of the territory and stated that “…schools and the means of education shall forever be encouraged.”

    In 1803, Ohio became a state and on February 18, 1804, the Ohio General Assembly passed an act establishing “The Ohio University.” The University opened in 1808 with one building, three students, and one professor, Jacob Lindley. One of the first two graduates of the University, Thomas Ewing, later became a United States senator and distinguished himself as cabinet member or advisor to four presidents.

    Twenty-four years after its founding, in 1828, Ohio University conferred an A.B. degree on John Newton Templeton, its first black graduate and only the third black man to graduate from a college in the United States. In 1873, Margaret Boyd received her B.A. degree and became the first woman to graduate from the University. Soon after, the institution graduated its first international alumnus, Saki Taro Murayama of Japan, in 1895.

  • richardmitnick 8:00 am on June 9, 2016 Permalink | Reply
    Tags: , , topological plexcitons,   

    From UCSD: “Scientists Design Energy-Carrying Particles Called ‘Topological Plexcitons’” 

    UC San Diego bloc

    UC San Diego

    June 09, 2016
    Kim McDonald

    Plexcitons travel for 20,000 nanometers, a length which is on the order of the width of human hair. Graphic by Joel Yuen-Zhou

    Scientists at UC San Diego, MIT and Harvard University have engineered “topological plexcitons,” energy-carrying particles that could help make possible the design of new kinds of solar cells and miniaturized optical circuitry.

    The researchers report their advance in an article* published in the current issue of Nature Communications.

    Within the Lilliputian world of solid state physics, light and matter interact in strange ways, exchanging energy back and forth between them.

    “When light and matter interact, they exchange energy,” explained Joel Yuen-Zhou, an assistant professor of chemistry and biochemistry at UC San Diego and the first author of the paper. “Energy can flow back and forth between light in a metal (so called plasmon) and light in a molecule (so called exciton). When this exchange is much faster than their respective decay rates, their individual identities are lost, and it is more accurate to think about them as hybrid particles; excitons and plasmons marry to form plexcitons.”

    Materials scientists have been looking for ways to enhance a process known as exciton energy transfer, or EET, to create better solar cells as well as miniaturized photonic circuits which are dozens of times smaller than their silicon counterparts.

    “Understanding the fundamental mechanisms of EET enhancement would alter the way we think about designing solar cells or the ways in which energy can be transported in nanoscale materials,” said Yuen-Zhou.

    The drawback with EET, however, is that this form of energy transfer is extremely short-ranged, on the scale of only 10 nanometers (a 100 millionth of a meter), and quickly dissipates as the excitons interact with different molecules.

    One solution to avoid those shortcomings is to hybridize excitons in a molecular crystal with the collective excitations within metals to produce plexcitons, which travel for 20,000 nanometers, a length which is on the order of the width of human hair.

    Plexcitons are expected to become an integral part of the next generation of nanophotonic circuitry, light-harvesting solar energy architectures and chemical catalysis devices. But the main problem with plexcitons, said Yuen-Zhou, is that their movement along all directions, which makes it hard to properly harness in a material or device.

    He and a team of physicists and engineers at MIT and Harvard found a solution to that problem by engineering particles called “topological plexcitons,” based on the concepts in which solid state physicists have been able to develop materials called “topological insulators.”

    “Topological insulators are materials that are perfect electrical insulators in the bulk but at their edges behave as perfect one-dimensional metallic cables,” Yuen-Zhou said. “The exciting feature of topological insulators is that even when the material is imperfect and has impurities, there is a large threshold of operation where electrons that start travelling along one direction cannot bounce back, making electron transport robust. In other words, one may think about the electrons being blind to impurities.”

    Plexcitons, as opposed to electrons, do not have an electrical charge. Yet, as Yuen-Zhou and his colleagues discovered, they still inherit these robust directional properties. Adding this “topological” feature to plexcitons gives rise to directionality of EET, a feature researchers had not previously conceived. This should eventually enable engineers to create plexcitonic switches to distribute energy selectively across different components of a new kind of solar cell or light-harvesting device.

    Other co-authors of the paper are Semion Saikin of Harvard and Tony Zhu, Mehmet Onbasli, Caroline Ross, Vladimir Bulovic and Marc Baldo of MIT. The research project was supported by grants from the U.S. Department of Energy, Defense Threat Reduction Agency and Solid-State Solar-Thermal Energy Conversion Center.

    *Scienc article:
    There is no link to this article. I have requested the link. If I get it, I will update this post.

    See the full article here .

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    UC San Diego Campus

    The University of California, San Diego (also referred to as UC San Diego or UCSD), is a public research university located in the La Jolla area of San Diego, California, in the United States.[12] The university occupies 2,141 acres (866 ha) near the coast of the Pacific Ocean with the main campus resting on approximately 1,152 acres (466 ha).[13] Established in 1960 near the pre-existing Scripps Institution of Oceanography, UC San Diego is the seventh oldest of the 10 University of California campuses and offers over 200 undergraduate and graduate degree programs, enrolling about 22,700 undergraduate and 6,300 graduate students. UC San Diego is one of America’s Public Ivy universities, which recognizes top public research universities in the United States. UC San Diego was ranked 8th among public universities and 37th among all universities in the United States, and rated the 18th Top World University by U.S. News & World Report ‘s 2015 rankings.

  • richardmitnick 10:31 am on June 3, 2016 Permalink | Reply
    Tags: AIDA, , , ,   

    From AIDA: “AIDA-2020: First Year in Review” 

    AIDA 2020 bloc

    Advanced European Infrastructures for Detectors at Accelerators

    Laurent Serin (CNRS)

    Group photo of project members attending the AIDA-2020 Kick-off meeting at CERN, June 2015 (Image: CERN)

    CMS Pixel Detector, Image credit: CMS

    View of the ATLAS calorimeters from below


    European XFEL Test module
    European XFEL Test module

    Following the success of the AIDA project, AIDA-2020 started one year ago in May 2015. The project groups a large fraction of the High Energy Physics R&D community in Europe, united in the goal of advancing detector technology and infrastructures for the future. The community represents most forms of detector technology and is very active in its work and networking.

    On Track is to serve as a newsletter for the AIDA-2020 project as well as the wider detector community. Its launch will allow the detector community at large to exchange information and results by highlighting new developments in the field and serving as an active source of news.

    Over its first year, the irradiation and test beam facilities supported by the Transnational Access programme were already going full speed. In addition, new facilities such as the micro beam at RBI in Croatia and the electromagnetic compatibility testing facility at ITAINNOVA in Spain had some of their first users under this programme. There are also ongoing improvements of tracking devices at DESY and CERN or upgraded irradiations facilities at CERN and JSI.

    There has been progress on each detector technology (pixels, calorimeter and gas detector) with qualification measurements, and beam tests are expected to be conducted over summer 2016, as well as dedicated meetings and tutorials on TCAD simulations.

    Silicon detectors used for energy and time measurements are among the new ways investigated by the collider experiments (CMS, ATLAS, CALICE). A dedicated workshop will be organized by AIDA-2020 on June 13th at DESY, during the first annual meeting, to initiate cross-experiment interactions between these key actors.

    I look forward to the first annual meeting at DESY (Hamburg, Germany) where we will be able to discuss the first year results and the activities of the coming year. After having managed AIDA and this first year of AIDA-2020 running well, it is also time for me to pass the baton to Felix Sefkow as the AIDA-2020 Scientific Coordinator. Felix will impulse new ideas for the project, and open it further to detector applications outside our field, guiding AIDA-2020 to new ventures in the years ahead.

    See the full article here .

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    What is AIDA-2020?

    The AIDA-2020 project brings together the leading European research infrastructures in the field of detector development and testing and a number of institutes, universities and technological centers, thus assembling the necessary expertise for the ambitious programme of work.
    Who is involved?

    In total, 24 countries and CERN are involved in a coherent and coordinated programme of NAs, TAs and JRAs, fully in line with the priorities of the European Strategy for Particle Physics.
    What benefits does AIDA-2020 offer?

    AIDA-2020 aims to advance detector technologies beyond current limits by offering well-equipped test beam and irradiation facilities for testing detector systems under its Transnational Access programme. Common software tools, micro-electronics and data acquisition systems are also provided. This shared high-quality infrastructure will ensure optimal use and coherent development, thus increasing knowledge exchange between European groups and maximising scientific progress. The project also exploits the innovation potential of detector research by engaging with European industry for large-scale production of detector systems and by developing applications outside of particle physics, e.g. for medical imaging.

    AIDA-2020 will lead to enhanced coordination within the European detector community, leveraging EU and national resources. The project will explore novel detector technologies and will provide the ERA with world-class infrastructure for detector development, benefiting thousands of researchers participating in future particle physics projects, and contributing to maintaining Europe’s leadership of the field.

  • richardmitnick 3:59 pm on May 27, 2016 Permalink | Reply
    Tags: , , Majorana fermions,   

    From Caltech: “Engineering Nanodevices to Store Information the Quantum Way” 

    Caltech Logo


    Jessica Stoller-Conrad

    Creating quantum computers which some people believe will be the next generation of computers, with the ability to outperform machines based on conventional technology—depends upon harnessing the principles of quantum mechanics, or the physics that governs the behavior of particles at the subatomic scale. Entanglement—a concept that Albert Einstein once called “spooky action at a distance”—is integral to quantum computing, as it allows two physically separated particles to store and exchange information.

    Stevan Nadj-Perge, assistant professor of applied physics and materials science. Credit: Photo courtesy of S. Nadj-Perge

    Stevan Nadj-Perge, assistant professor of applied physics and materials science, is interested in creating a device that could harness the power of entangled particles within a usable technology. However, one barrier to the development of quantum computing is decoherence, or the tendency of outside noise to destroy the quantum properties of a quantum computing device and ruin its ability to store information.

    Nadj-Perge, who is originally from Serbia, received his undergraduate degree from Belgrade University and his PhD from Delft University of Technology in the Netherlands. He received a Marie Curie Fellowship in 2011, and joined the Caltech Division of Engineering and Applied Science in January after completing postdoctoral appointments at Princeton and Delft.

    He recently talked with us about how his experimental work aims to resolve the problem of decoherence.

    What is the overall goal of your research?

    A large part of my research is focused on finding ways to store and process quantum information. Typically, if you have a quantum system, it loses its coherent properties—and therefore, its ability to store quantum information—very quickly. Quantum information is very fragile and even the smallest amount of external noise messes up quantum states. This is true for all quantum systems. There are various schemes that tackle this problem and postpone decoherence, but the one that I’m most interested in involves Majorana fermions. These particles were proposed to exist in nature almost eighty years ago but interestingly were never found.

    Relatively recently theorists figured out how to engineer these particles in the lab. It turns out that, under certain conditions, when you combine certain materials and apply high magnetic fields at very cold temperatures, electrons will form a state that looks exactly as you would expect from Majorana fermions. Furthermore, such engineered states allow you to store quantum information in a way that postpones decoherence.

    How exactly is quantum information stored using these Majorana fermions?

    The fascinating property of these particles is that they always come in pairs. If you can store information in a pair of Majorana fermions it will be protected against all of the usual environmental noise that affects quantum states of individual objects. The information is protected because it is not stored in a single particle but in the pair itself. My lab is developing ways to engineer nanodevices which host Majorana fermions. Hopefully one day our devices will find applications in quantum computing.

    Why did you want to come to Caltech to do this work?

    The concept of engineered Majorana fermions and topological protection was, to a large degree, conceived here at Caltech by Alexei Kiteav [Ronald and Maxine Linde Professor of Theoretical Physics and Mathematics] who is in the physics department. A couple of physicists here at Caltech, Gil Refeal [professor of theoretical physics and executive officer of physics] and Jason Alicea [professor of theoretical physics], are doing theoretical work that is very relevant for my field.

    Do you have any collaborations planned here?

    Nothing formal, but I’ve been talking a lot with Gil and Jason. A student of mine also uses resources in the lab of Harry Atwater [Howard Hughes Professor of Applied Physics and Materials Science and director of the Joint Center for Artificial Photosynthesis], who has experience with materials that are potentially useful for our research.

    How does that project relate to your lab’s work?

    There are two-dimensional, or 2-D, materials that are basically very thin sheets of atoms. Graphene—a single layer of carbon atoms—is one example, but you can create single layer sheets of atoms with many materials. Harry Atwater’s group is working on solar cells made of a 2-D material. We are thinking of using the same materials and combining them with superconductors—materials that can conduct electricity without releasing heat, sound, or any other form of energy—in order to produce Majorana fermions.

    How do you do that?

    There are several proposed ways of using 2-D materials to create Majorana fermions. The majority of these materials have a strong spin-orbit coupling—an interaction of a particle’s spin with its motion—which is one of the key ingredients for creating Majoranas. Also some of the 2-D materials can become superconductors at low temperatures. One of the ideas that we are seriously considering is using a 2-D material as a substrate on which we could build atomic chains that will host Majorana fermions

    What got you interested in science when you were young?

    I don’t come from a family of scientists; my father is an engineer and my mother is an administrative worker. But my father first got me interested in science. As an engineer, he was always solving something and he brought home some of the problems he was working. I worked with him and picked it up at an early age.

    How are you adjusting to life in California?

    Well, I like being outdoors, and here we have the mountains and the beach and it’s really amazing. The weather here is so much better than the other places I’ve lived. If you want to get the impression of what the weather in the Netherlands is like, you just replace the number of sunny days here with the number of rainy days there.

    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.”
    Caltech buildings

  • richardmitnick 12:57 pm on May 25, 2016 Permalink | Reply
    Tags: , Has a Hungarian physics lab found a fifth force of nature?, ,   

    From Nature: “Has a Hungarian physics lab found a fifth force of nature?” 

    Nature Mag

    25 May 2016
    Edwin Cartlidge

    Physicists at the Institute for Nuclear Research in Debrecen, Hungary, say this apparatus — an electron-positron spectrometer — has found evidence for a new particle.

    A laboratory experiment in Hungary has spotted an anomaly in radioactive decay that could be the signature of a previously unknown fifth fundamental force of nature, physicists say – if the finding holds up.

    Attila Krasznahorkay at the Hungarian Academy of Sciences’s Institute for Nuclear Research in Debrecen, Hungary, and his colleagues reported their surprising result* in 2015 on the arXiv preprint server, and this January in the journal Physical Review Letters. But the report – which posited the existence of a new, light boson only 34 times heavier than the electron – was largely overlooked.

    Then, on 25 April, a group of US theoretical physicists brought the finding to wider attention by publishing its own analysis of the result** on arXiv2. The theorists showed that the data didn’t conflict with any previous experiments – and concluded that it could be evidence for a fifth fundamental force. “We brought it out from relative obscurity,” says Jonathan Feng, at the University of California, Irvine, the lead author of the arXiv report.

    Four days later, two of Feng’s colleagues discussed the finding at a workshop at the SLAC National Accelerator Laboratory in Menlo Park, California. Researchers there were sceptical but excited about the idea, says Bogdan Wojtsekhowski, a physicist at the Thomas Jefferson National Accelerator Facility in Newport News, Virginia. “Many participants in the workshop are thinking about different ways to check it,” he says. Groups in Europe and the United States say that they should be able to confirm or rebut the Hungarian experimental results within about a year.

    Search for new forces

    Gravity, electromagnetism and the strong and weak nuclear forces are the four fundamental forces known to physics — but researchers have made many as-yet unsubstantiated claims of a fifth. Over the past decade, the search for new forces has ramped up because of the inability of the standard model of particle physics to explain dark matter — an invisible substance thought to make up more than 80% of the Universe’s mass.

    The Standard Model of elementary particles (more schematic depiction), with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.
    The Standard Model of elementary particles (more schematic depiction), with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.

    Theorists have proposed various exotic-matter particles and force-carriers, including “dark photons”, by analogy to conventional photons that carry the electromagnetic force.

    Krasznahorkay says his group was searching for evidence of just such a dark photon – but Feng’s team think they found something different. The Hungarian team fired protons at thin targets of lithium-7, which created unstable beryllium-8 nuclei that then decayed and spat out pairs of electrons and positrons. According to the standard model, physicists should see that the number of observed pairs drops as the angle separating the trajectory of the electron and positron increases. But the team reported that at about 140º, the number of such emissions jumps — creating a ‘bump’ when the number of pairs are plotted against the angle — before dropping off again at higher angles.

    Bump in confidence

    Krasznahorkay says that the bump is strong evidence that a minute fraction of the unstable beryllium-8 nuclei shed their excess energy in the form of a new particle, which then decays into an electron–positron pair. He and his colleagues calculate the particle’s mass to be about 17 megaelectronvolts (MeV).

    “We are very confident about our experimental results,” says Krasznahorkay. He says that the team has repeated its test several times in the past three years, and that it has eliminated every conceivable source of error. Assuming it has done so, then the odds of seeing such an extreme anomaly if there were nothing unusual going on are about 1 in 200 billion, the team says.

    Feng and colleagues say that the 17-MeV particle is not a dark photon. After analysing the anomaly and looking for properties consistent with previous experimental results, they concluded that the particle could instead be a “protophobic X boson”. Such a particle would carry an extremely short-range force that acts over distances only several times the width of an atomic nucleus. And where a dark photon (like a conventional photon) would couple to electrons and protons, the new boson would couple to electrons and neutrons. Feng says that his group is currently investigating other kinds of particles that could explain the anomaly. But the protophobic boson is “the most straightforward possibility”, he says.

    Unconventional coupling

    Jesse Thaler, a theoretical physicist at the Massachusetts Institute of Technology (MIT) in Cambridge, says that the unconventional coupling proposed by Feng’s team makes him sceptical that the new particle exists. “It certainly isn’t the first thing I would have written down if I were allowed to augment the standard model at will,” he says. But he adds that he is “paying attention” to the proposal. “Perhaps we are seeing our first glimpse into physics beyond the visible Universe,” he says.

    Researchers should not have to wait long to find out whether a 17-MeV particle really does exist. The DarkLight experiment at the Jefferson Laboratory is designed to search for dark photons with masses of 10–100 MeV, by firing electrons at a hydrogen gas target. Now, says collaboration spokesperson Richard Milner of MIT, it will target the 17-MeV region as a priority, and within about a year, could either find the proposed particle or set stringent limits on its coupling with normal matter.

    Also searching for the proposed boson will be the LHCb experiment at CERN, Europe’s particle-physics lab near Geneva, which will study quark–antiquark decays, and two experiments that will fire positrons at a fixed target — one at the INFN Frascati National Laboratory near Rome, due to switch on in 2018, and the other at the Budker Institute of Nuclear Physics in the Siberian town of Novosibirsk, Russia.

    Rouven Essig, a theoretical physicist at Stony Brook University in New York and one of the organizers of the SLAC workshop, thinks that the boson’s “somewhat unexpected” properties make a confirmation unlikely. But he welcomes the tests. “It would be crazy not to do another experiment to check this result,” he says. “Nature has surprised us before!”

    *Science paper:
    Observation of Anomalous Internal Pair Creation in 8Be: A Possible Signature of a Light, Neutral Boson

    **Science paper:
    Evidence for a Protophobic Fifth Force from 8Be Nuclear Transitions

    See the full article here .

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    Nature is a weekly international journal publishing the finest peer-reviewed research in all fields of science and technology on the basis of its originality, importance, interdisciplinary interest, timeliness, accessibility, elegance and surprising conclusions. Nature also provides rapid, authoritative, insightful and arresting news and interpretation of topical and coming trends affecting science, scientists and the wider public.

  • richardmitnick 7:49 am on May 21, 2016 Permalink | Reply
    Tags: , , Planck scale,   

    From Symmetry: “The Planck scale” 

    Symmetry Mag


    Rashmi Shivni

    The Planck scale sets the universe’s minimum limit, beyond which the laws of physics break.

    Illustration by Sandbox Studio, Chicago with Corinne Mucha

    In the late 1890s, physicist Max Planck proposed a set of units to simplify the expression of physics laws. Using just five constants in nature (including the speed of light and the gravitational constant), you, me and even aliens from Alpha Centauri could arrive at these same Planck units.

    The basic Planck units are length, mass, temperature, time and charge.

    Let’s consider the unit of Planck length for a moment. The proton is about 100 million trillion times larger than the Planck length. To put this into perspective, if we scaled the proton up to the size of the observable universe, the Planck length would be a mere trip from Tokyo to Chicago. The 14-hour flight may seem long to you, but to the universe, it would go completely unnoticed.

    The Planck scale was invented as a set of universal units, so it was a shock when those limits also turned out to be the limits where the known laws of physics applied. For example, a distance smaller than the Planck length just doesn’t make sense—the physics breaks down.

    Physicists don’t know what actually goes on at the Planck scale, but they can speculate. Some theoretical particle physicists predict all four fundamental forces—gravity, the weak force, electromagnetism and the strong force—finally merge into one force at this energy. Quantum gravity and superstrings are also possible phenomena that might dominate at the Planck energy scale.

    The Planck scale is the universal limit, beyond which the currently known laws of physics break. In order to comprehend anything beyond it, we need new, unbreakable physics.

    See the full article here .

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    Symmetry is a joint Fermilab/SLAC publication.

  • richardmitnick 6:39 am on May 20, 2016 Permalink | Reply
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    From CERN: “In Theory: Is theoretical physics in crisis?” 

    Cern New Bloc

    Cern New Particle Event

    CERN New Masthead


    20 May 2016
    Harriet Jarlett

    “The way physics develops is often a lot less logical than the theories it leads to — you cannot plan discoveries. Especially in theoretical physics.” Gian Giudice, Head of CERN’s Theory Department (Image: Sophia Bennett/ CERN)

    Over the past decade physicists have explored new corners of our world, and in doing so have answered some of the biggest questions of the past century.

    When researchers discovered the Higgs boson in 2012, it was a huge moment of achievement.

    CERN CMS Higgs Event
    CERN CMS Higgs Event

    It showed theorists had been right to look towards the Standard Model for answers about our Universe.

    The Standard Model of elementary particles (more schematic depiction), with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.
    The Standard Model of elementary particles (more schematic depiction), with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.

    But then the particle acted just like the theorist’s said it would, it obeyed every rule they predicted. If it had acted just slightly differently it would have raised many questions about the theory, and our universe. Instead, it raised few questions and gave no new clues about to where to look next.

    In other words, the theorists had done too good a job.

    “We are struggling to find clear indications that can point us in the right direction. Some people see in this state of crisis a source of frustration. I see a source of excitement because new ideas have always thrived in moments of crisis.” – Gian Giudice, head of the Theory Department at CERN.

    Before these discoveries, physicists were standing on the edge of a metaphorical flat Earth, suspecting it was round but not knowing for sure. Finding both the Higgs boson, and evidence of gravitational waves has brought scientists closer than ever to understanding two of the great theories of our time – the Standard Model and the theory of relativity.

    Now the future of theoretical physics is at a critical point – they proved their own theories, so what is there to do now?

    So what next?

    “Taking unexplained data, trying to fit it to the ideas of the universe […] – that’s the spirit of theoretical physics” – Gian Giudice

    In an earlier article in this series [link to series is below], we spoke about how experimental physicists and theoretical physicists must work together. Their symbiotic relationship – with theorists telling experimentalists where to look, and experimentalists asking theorists for explanations of unusual findings – is necessary, if we are to keep making discoveries.

    Just four years ago, in 2012, physicists still held a genuine uncertainty about whether the lynchpin of the Standard Model, the Higgs boson existed at all. Now, there’s much less uncertainty.

    “We are still in an uncertain period, previously we were uncertain as to how the Standard Model could be completed. Now we know it is pretty much complete so we can focus on the questions beyond it, dark matter, the future of the universe, the beginning of the universe, little things like that,” says John Ellis, a theoretical physicist from Kings College, London who began working at CERN since 1973.

    Michelangelo Mangano moved to the US to work at Princeton just as String Theory was made popular. “After the first big explosion of interest, there’s always a period of slowing down, because all the easier stuff has been done. And you’re struggling with more complex issues,” he explains. “This is something that today’s young theorists are finding as they struggle to make waves in fields like the Standard Model. Unexpected findings from the LHC could reignite their enthusiasm and help younger researchers to feel like they can have an impact.” (Image: Maximillien Brice/CERN)

    With the discovery of the Higgs, there’s been a shift in this relationship, with theoreticians not necessarily leading the way. Instead, experiments look for data to try and give more evidence to the already proposed theories, and if something new is thrown up theorists scramble to explain and make sense of it.

    “It’s like when you go mushroom hunting,” says Michelangelo Mangano, a theoretical physicist who works closely with experimental physicists. “You spend all your energy looking, and at the end of the day you may not find anything. Here it’s the same, there is a lots of wasted energy because it doesn’t lead to much, but by exploring all corners of the field occasionally you find a little gold nugget, a perfect mushroom.”

    At the end of last year, both the ATLAS and CMS experiments at CERN found their mushroom, an intriguing, albeit very small, bump in the data.

    This little, unexpected bump could be the door to a whole host of new physics, because it could be a new particle. After the discovery of the Higgs most of the holes in the Standard Model had been sewn up, but many physicists were optimistic about finding new anomalies.

    “What happens in the future largely depends on what the LHC finds in its second run,” Ellis explains. “So if it turns out that there’s no other new physics and we’re focusing on understanding the Higgs boson better, that’s a different possible future for physics than if LHC Run 2 finds a new particle we need to understand.”

    While the bump is too small for physicists to announce it conclusively, there’s been hundreds of papers published by theoretical physicists as they leap to say what it might be.

    “Taking unexplained data, trying to fit it to your ideas about the universe, revising your ideas once you get more data, and on and on until you have unravelled the story of the universe – that’s the spirit of theoretical physics,” expresses Giudice.

    John Ellis classifies himself as a ‘scientific optimist’, who is happy to pick up whatever tools are available to him to help solve the problems that he has thought up. ‘By nature I’m an optimist so anything can happen, yes, we might not see anything beyond the Higgs boson, but lets just wait and see.’ Here he is interviewed by Harriet Jarlett (left) in his office at CERN. (Image: Sophia Bennett/CERN)

    But we’ll only know whether it’s something worthwhile with the start of the LHC this month, May 2016, when experimental physicists can start to take even more data and conclude what it is.

    Next generation of theory

    This unusual period of quiet in the world of theoretical physics means students studying physics might be more likely to go into experimental physics, where the major discoveries are seen as happening more often, and where young physicists have a chance to be the first to a discovery.

    Speaking to the Summer Students at CERN, some of whom hope to become theoretical physicists, there is the feeling that this period of uncertainty makes following theory a luxury, one that young physicists, who need to have original ideas and publish lots of papers to get ahead, can’t afford.

    Camille Bonvin is working as a fellow in the Theory Department on cosmology to try and understand why the universe is accelerating. If gravity is described by Einstein’s theory of general relativity the expansion should be slowing, not accelerating, which means there’s something we don’t understand. Bonvin is trying to find out what that is. Bonvin thinks the best theories are simple, consistent and make sense, like general relativity. “Einstein is completely logical, and his theory makes sense. Sometimes you have the impression of taking a theory which already exists and adding one element, then another, then another, to try and make the data fit it better, but its not a fundamental theory, so for me its not extremely beautiful.” (Image: Sophia Bennett/CERN)

    Camille Bonvin, a young theoretical physicist at CERN hopes that the data bump is the key to new physics, because without new discoveries it’s hard to keep a younger generation interested: “If both the LHC and the upcoming cosmological surveys find no new physics, it will be difficult to motivate new theorists. If you don’t know where to go or what to look for, it’s hard to see in which direction your research should go and which ideas you should explore.”

    The future’s bright

    Richard Feynman

    Richard Feynman, one of the most famous theoretical physicists once joked, “Physics is like sex. Sure, it may give some practical results, but that’s not why we do it.”

    And Gian Giudice agrees –while the field’s current uncertainty makes it more difficult for young people to make breakthroughs, it’s not the promise of glory that encourages people to follow the theory path, but just a simple passion in why our universe is the way it is.

    “It must be difficult for the new generations of young researchers to enter theoretical physics now when it is not clear where different directions are leading to,” he says. “But it’s much more interesting to play when you don’t know what’s going to happen, rather than when the rules of the game have already been settled.”

    “It’s much more interesting to play when you don’t know what’s going to happen, rather than when the rules of the game have already been settled,” says Giudice, who took on the role of leading the department in 2016 (Image: Sophia Bennett/ CERN) (Image: Sophia Bennett/CERN)

    Giudice, who took on the role of leading the theory department in January 2016 is optimistic that the turbulence the field currently faces makes it one of the most exciting times to become a theoretical physicist.

    “It has often been said that it is difficult to make predictions; especially about the future. It couldn’t be more true today in particle physics. This is what makes the present so exciting. Looking back in the history of physics you’ll see that moments of crisis and confusion were invariably followed by great revolutionary ideas. I hope it’s about to happen again,” smiles Giudice.

    See the full article here.

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    Meet CERN in a variety of places:

    Cern Courier




    CERN CMS New

    CERN LHCb New II


    CERN LHC Map
    CERN LHC Grand Tunnel

    CERN LHC particles

    Quantum Diaries

  • richardmitnick 12:13 pm on May 19, 2016 Permalink | Reply
    Tags: Alexander Zamolodchikov, , ,   

    From Rutgers: “Rutgers Physics Professor Elected to National Academy of Sciences” 

    Rutgers University
    Rutgers University

    May 16, 2016

    Todd Bates

    Alexander Zamolodchikov, a renowned professor of physics at Rutgers University, has been elected to the prestigious National Academy of Sciences.

    He joins 83 other newly elected members and 21 foreign associates from 14 countries. They were named in recognition of their distinguished and ongoing research achievements, according to the academy. New members will be formally inducted into the academy at its annual meeting next year.

    “I am pleased and excited, and I will be greatly honored to become a part of this distinguished institution,” Zamolodchikov said. “I regard this as recognition of the overall importance of the area of theoretical physics which I, along with my colleagues at Rutgers and around the world, have helped to develop.”

    Photo: Alexander Zamolodchikov, professor of physics at Rutgers University. Courtesy of Alexander Zamolodchikov

    Zamolodchikov, known as Sasha, is a native of Dubna in the Moscow Region of Russia. He’s conducted groundbreaking research in theoretical and mathematical physics, focusing on quantum field theories and statistical physics. His most notable research is in the areas of conformal and integrable quantum field theories.

    Zamolodchikov, Board of Governors professor of physics at Rutgers, earned a master’s degree in nuclear physics and engineering at the Moscow Institute of Physics and Technology. He earned a doctorate in theoretical and mathematical physics at the Institute of Theoretical and Experimental Physics in Moscow in 1978.

    Zamolodchikov was a researcher at the L.D. Landau Institute for Theoretical Physics in Moscow from 1978 to 1990, when he became a professor of physics at Rutgers. He became a Board of Governor’s professor of physics at Rutgers in 2005.

    Zamolodchikov has won numerous awards and honors, including: the Lenin Komsomol Prize; American Physical Society Dannie Heineman Prize for Mathematical Physics; Alexander von Humboldt Research Award; Chair Blaise Pascal; American Physical Society Lars Onsager Prize; ICTP Dirac Medal; and Pomeranchuk Prize. He is a fellow of the American Physical Society and a member of the American Academy of Arts and Sciences. He also won a John Simon Guggenheim Memorial Foundation Fellowship.

    With its recent announcement, the National Academy of Sciences now has 2,291 active members, along with 465 foreign associates. Foreign associates are nonvoting members who are not U.S. citizens.

    The National Academy of Sciences – a private, nonprofit institution established in 1863 under a congressional charter signed by President Abraham Lincoln – recognizes achievement in science. It provides science, technology and health policy advice to the federal government and other organizations through the National Academy of Engineering, Institute of Medicine and National Research Council.

    See the full article here .

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    Rutgers, The State University of New Jersey, is a leading national research university and the state’s preeminent, comprehensive public institution of higher education. Rutgers is dedicated to teaching that meets the highest standards of excellence; to conducting research that breaks new ground; and to providing services, solutions, and clinical care that help individuals and the local, national, and global communities where they live.

    Founded in 1766, Rutgers teaches across the full educational spectrum: preschool to precollege; undergraduate to graduate; postdoctoral fellowships to residencies; and continuing education for professional and personal advancement.

    Rutgers Original seal

  • richardmitnick 12:05 pm on May 14, 2016 Permalink | Reply
    Tags: , , , Six physics equations that changed the course of history   

    From COSMOS: “Six physics equations that changed the course of history” 

    Cosmos Magazine bloc


    3 May 2016 [this just appeared in social media]
    Cathal O’Connell

    Illustration: Alison Mackey/Discover, Apple: Thinkstock

    Physics equations are forms of magic. They allow us to explain the past, such as why Halley’s comet visits every 76 years, and predict the future – as far as the ultimate fate of the Universe.

    They place limits on the possible, as in the efficiency of an engine, and they reveal possibilities we could never have imagined, such as the energy inside an atom.

    Occasionally over the past few centuries, a new equation endowed the next generation with a new magical tool, and so changed the course of history. Here are some of the most pivotal.

    1. Newton’s second law of motion (1687)

    What does it say?

    Force equals mass times acceleration.

    In other words …

    It’s easier to push an empty shopping cart than a full one.

    What did it teach us?

    Together with Isaac Newton’s other two laws of motion (the first says you need a force to move something, the third says every action has an equal and opposite reaction), this equation forms the foundation of classical mechanics.

    F=ma allowed physicists and engineers to calculate the value of a force. For instance, your weight (measured in newtons) is your mass (in kilograms) multiplied by acceleration due to gravity (on Earth, about 10 metres per second squared).

    Saying you “weigh” 60 kilograms is incorrect in physics terms – your actual weight is about 600 newtons. This is the force pushing down on your bathroom scales.

    But was it practical?

    This equation was crucial to the arrival of the mechanical age. It’s used in almost every calculation which involves using force to cause movement.

    It tells you how powerful an engine needs to be to power a car, how much lift an aircraft needs to take-off, how much thrust to lift a rocket, how far a cannonball flies.

    2. Newton’s law of universal gravitation (1687)
    What does it say?

    Any two massive objects pull on one another across space. But the force decreases rapidly the further apart they are.

    In other words …

    We’re stuck to the Earth’s surface because our planet is comparatively big with lots more mass.

    What did it teach us?

    For centuries, the Universe had been divided into two realms – the earthly and the celestial. But Newton’s law of gravitation applied to everything. The same tug that causes an apple to fall from a tree keeps the Moon orbiting the Earth. Newton gave us the first direct connection between everyday life and the movement of the heavens.

    But was it practical?

    For a long time, the equation’s main use was to calculate the orbits of planets. The space-age of the 1950s and 60s saw it used in practice – to send satellites into orbit and astronauts to the Moon.

    One failing, which Newton himself admitted, was that he did not know “why” gravity operated. It took nearly 230 years for Albert Einstein to come along and explain gravity as arising from the warping of spacetime by massive objects in his theory of general relativity.

    Even so, general relativity is only used in extreme situations, such as when gravity is very strong, or when great precision is required, such as for GPS satellites. In most cases Newton’s 330-year-old equation is still good enough.

    4. The Maxwell-Faraday equation (1831 and 1865)
    What does it say?

    You can create a changing electric field (left side of the equation) from a changing magnetic field (on the right) and vice versa.

    In other words …

    Electricity and magnetism are related!

    What did it teach us?

    In 1831, Michael Faraday discovered the connection between two natural forces, electricity and magnetism, when he found a changing magnetic field induced a current in a nearby wire.

    Later, James Clark Maxwell generalised Faraday’s observation as one of his four fundamental equations of electromagnetism.

    But was it practical?

    This is the equation that powers the world. Most electric generators (whether in a wind turbine, coal-fired plant or a hydroelectric dam) work by converting mechanical energy (from steam or water) to rotate a magnet. By running this process in reverse, you get the electric motor.

    More generally, Maxwell’s equations are still used in almost every application of electrical engineering, communications technology and optics.

    5. Einstein’s mass-energy equivalence (1905)
    What does it say?

    Energy equals mass multiplied by the speed of light squared.
    In other words …

    Mass is really just a super-condensed form of energy.

    What did it teach us?

    Because of the size of the constant in the equation (the speed of light squared, an unimaginably huge number) a colossal amount of energy can be released through converting a tiny amount of mass.

    But was it practical?

    Einstein’s most famous equation hinted at the potential for the huge amounts of energy released in nuclear fission, when a large unstable nucleus breaks into two smaller ones. This is because the mass of the two smaller nuclei together is always less than the mass of the original big nucleus – and the missing mass is converted into energy.

    The “Fat Man” atomic bomb dropped over Nagasaki in Japan on 9 August 1945 converted just one gram of mass to energy, but produced an explosion the equivalent around 20,000 tonnes of TNT.

    Einstein himself had signed a letter to US president at the time Franklin Roosevelt recommending the atom bomb be developed – a decision he later regarded as the “one great mistake” of his life.

    6. The Schrödinger wavefunction (1925)
    What does it say?

    It describes how the change of a particle’s wavefunction (represented by psi, the candlestick shaped symbol) can be calculated from its kinetic energy (movement) and its potential energy (the interactions on it).

    In other words …

    It’s the quantum version of F=ma.

    What did it teach us?

    When Erwin Schrödinger formulated his equation in 1925, it placed the new theory of quantum mechanics on firm footing by allowing physicists to calculate how quantum particles move and interact.

    The equation looks a bit weird because it uses the mathematics of waves. (Subatomic particles are “wavy”, so their interaction is described as interference of waves, rather than like billiard balls.)

    But was it practical?

    In one of its simplest forms, it describes the structure of the atom, such as the arrangement of electrons around the nucleus, and all chemical bonding.

    More generally it’s used for many calculations in quantum mechanics and is fundamental to much of modern technology from lasers to transistors, and the future development of quantum computers

    See the full article here .

    Please help promote STEM in your local schools.

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    • clearskies2016 5:29 am on May 15, 2016 Permalink | Reply

      You really explained it so I can understand! Thank you. I will be referring to this article a lot this week as I go into more detail on them. Thank you!


    • richardmitnick 7:30 am on May 15, 2016 Permalink | Reply

      Thanks, But it was Cathal O’Connell at COSMOS who explained it, I just presented it here.
      Thanks for reading and “liking” my stuff.


  • richardmitnick 10:15 am on May 13, 2016 Permalink | Reply
    Tags: , Brane theory and testing, ,   

    From physicsworld: “Parallel-universe search focuses on neutrons” 


    May 10, 2016
    Edwin Cartlidge

    No braner: there is no evidence that ILL neutrons venture into an adjacent universe. No image credit.

    The first results* from a detector designed to look for evidence of particles reaching us from a parallel universe have been unveiled by physicists in France and Belgium. Although they drew a blank, the researchers say that their experiment provides a simple, low-cost way of testing theories beyond the Standard Model of particle physics, and that the detector could be made significantly more sensitive in the future.

    Standard Model
    The Standard Model of elementary particles (more schematic depiction), with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.

    A number of quantum theories of gravity predict the existence of dimensions beyond the three of space and one of time that we are familiar with. Those theories envisage our universe as a 4D surface or “brane” in a higher-dimensional space–time “bulk”, just as a 2D sheet of paper exists as a surface within our normal three spatial dimensions. The bulk could contain multiple branes separated from one another by a certain distance within the higher dimensions.

    Physicists have found no empirical evidence for the existence of other branes. However, in 2010, Michaël Sarrazin of the University of Namur in Belgium and Fabrice Petit of the Belgian Ceramic Research Centre put forward a model showing that particles normally trapped within one brane should occasionally be able to tunnel quantum mechanically into an adjacent brane. They said that neutrons should be more affected than charged particles because the tunnelling would be hindered by electromagnetic interactions.

    Nearest neighbour

    The researchers have now teamed up with physicists at the University of Grenoble in France and others at the University of Namur to put their model to the test. This involved setting up a helium-3 detector a few metres from the nuclear reactor at the Institut Laue-Langevin (ILL) in Grenoble and then recording how many neutrons it intercepted. The idea is that neutrons emitted by the reactor would exist in a quantum superposition of being in our brane and being in an adjacent brane (leaving aside the effect of more distant branes). The neutrons’ wavefunctions would then collapse into one or other of the two states when colliding with nuclei within the heavy-water moderator that surrounds the reactor core.

    Most neutrons would end up in our brane, but a small fraction would enter the adjacent one. Those neutrons, so the reasoning goes, would – unlike the neutrons in our brane – escape the reactor, because they would interact extremely weakly with the water and concrete shielding around it. However, because a tiny part of those neutrons’ wavefunction would still exist within our brane even after the initial collapse, they could return to our world by colliding with helium nuclei in the detector. In other words, there would be a small but finite chance that some neutrons emitted by the reactor would disappear into another universe before reappearing in our own – so registering events in the detector.

    Sarrazin says that the biggest challenge in carrying out the experiment was minimizing the considerable background flux of neutrons caused by leakage from neighbouring instruments within the reactor hall. He and his colleagues did this by enclosing the detector in a multilayer shield – a 20 cm-thick polyethylene box on the outside to convert fast neutrons into thermal ones and then a boron box on the inside to capture thermal neutrons. This shielding reduced the background by about a factor of a million.

    Stringent upper limit

    Operating their detector over five days in July last year, Sarrazin and colleagues recorded a small but still significant number of events. The fact that these events could be residual background means they do not constitute evidence for hidden neutrons, say the researchers. But they do allow for a new upper limit on the probability that a neutron enters a parallel universe when colliding with a nucleus – one in two billion, which is about 15,000 times more stringent than a limit the researchers had previously arrived at by studying stored ultra-cold neutrons. This new limit, they say, implies that the distance between branes must be more than 87 times the Planck length (about 1.6 × 10–35 m).

    To try and establish whether any of the residual events could indeed be due to hidden neutrons, Sarrazin and colleagues plan to carry out further, and longer, tests at ILL in about a year’s time. Sarrazin points out that because their model doesn’t predict the strength of inter-brane coupling, these tests cannot be used to completely rule out the existence of hidden branes. Conversely, he says, they could provide “clear evidence” in support of branes, which, he adds, could probably not be obtained using the LHC at CERN. “If the brane energy scale corresponds to the Planck energy scale, there is no hope to observe this kind of new physics in a collider,” he says.

    Axel Lindner of DESY, who carries out similar “shining-particles-through-a-wall” experiments (but using photons rather than neutrons), supports the latest research. He believes it is “very important” to probe such “crazy” ideas experimentally, given presently limited indications about what might supersede the Standard Model. “It would be highly desirable to clarify whether the detected neutron signals can really be attributed to background or whether there is something else behind it,” he says.

    The research is described in Physics Letters B.

    *Science paper:
    Search for passing-through-walls neutrons constrains hidden braneworlds

    See the full article here .

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    PhysicsWorld is a publication of the Institute of Physics. The Institute of Physics is a leading scientific society. We are a charitable organisation with a worldwide membership of more than 50,000, working together to advance physics education, research and application.

    We engage with policymakers and the general public to develop awareness and understanding of the value of physics and, through IOP Publishing, we are world leaders in professional scientific communications.
    IOP Institute of Physics

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