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  • richardmitnick 7:42 pm on January 16, 2020 Permalink | Reply
    Tags: "Study finds billions of quantum entangled electrons in ‘strange metal", , , Physics, , Quantum entanglement is the basis for storage and processing of quantum information., , Terahertz spectroscopy, With strange metals there is an unusual connection between electrical resistance and temperature.   

    From Rice University: “Study finds billions of quantum entangled electrons in ‘strange metal” 

    Rice U bloc

    From Rice University

    January 16, 2020
    Jade Boyd

    Physicists provide direct evidence of entanglement’s role in quantum criticality.

    In a new study, U.S. and Austrian physicists have observed quantum entanglement among “billions of billions” of flowing electrons in a quantum critical material.

    Junichiro Kono (left) and Qimiao Si in Kono’s Rice University laboratory in December 2019. (Photo by Jeff Fitlow/Rice University)

    The research, which appears this week in Science, examined the electronic and magnetic behavior of a “strange metal” compound of ytterbium, rhodium and silicon as it both neared and passed through a critical transition at the boundary between two well-studied quantum phases.

    The study at Rice University and Vienna University of Technology (TU Wien) provides the strongest direct evidence to date of entanglement’s role in bringing about quantum criticality, said study co-author Qimiao Si of Rice.

    “When we think about quantum entanglement, we think about small things,” Si said. “We don’t associate it with macroscopic objects. But at a quantum critical point, things are so collective that we have this chance to see the effects of entanglement, even in a metallic film that contains billions of billions of quantum mechanical objects.”

    Si, a theoretical physicist and director of the Rice Center for Quantum Materials (RCQM), has spent more than two decades studying what happens when materials like strange metals and high-temperature superconductors change quantum phases. Better understanding such materials could open the door to new technologies in computing, communications and more.

    The international team overcame several challenges to get the result. TU Wien researchers developed a highly complex materials synthesis technique to produce ultrapure films containing one part ytterbium for every two parts rhodium and silicon (YbRh2Si2). At absolute zero temperature, the material undergoes a transition from one quantum phase that forms a magnetic order to another that does not.

    Physicist Silke Bühler-Paschen of the Vienna University of Technology (Photo by Luisa Puiu/TU Wien)

    At Rice, study co-lead author Xinwei Li, then a graduate student in the lab of co-author and RCQM member Junichiro Kono, performed terahertz spectroscopy experiments on the films at temperatures as low as 1.4 Kelvin. The terahertz measurements revealed the optical conductivity of the YbRh2Si2 films as they were cooled to a quantum critical point that marked the transition from one quantum phase to another.

    “With strange metals, there is an unusual connection between electrical resistance and temperature,” said corresponding author Silke Bühler-Paschen of TU Wien’s Institute for Solid State Physics. “In contrast to simple metals such as copper or gold, this does not seem to be due to the thermal movement of the atoms, but to quantum fluctuations at the absolute zero temperature.”

    To measure optical conductivity, Li shined coherent electromagnetic radiation in the terahertz frequency range on top of the films and analyzed the amount of terahertz rays that passed through as a function of frequency and temperature. The experiments revealed “frequency over temperature scaling,” a telltale sign of quantum criticality, the authors said.

    Kono, an engineer and physicist in Rice’s Brown School of Engineering, said the measurements were painstaking for Li, who’s now a postdoctoral researcher at the California Institute of Technology. For example, only a fraction of the terahertz radiation shined onto the sample passed through to the detector, and the important measurement was how much that fraction rose or fell at different temperatures.

    Former Rice University graduate student Xinwei Li in 2016 with the terahertz spectrometer he later used to measure entanglement in the conduction electrons flowing through a “strange metal” compound of ytterbium, rhodium and silicon. (Photo by Jeff Fitlow/Rice University)

    “Less than 0.1% of the total terahertz radiation was transmitted, and the signal, which was the variation of conductivity as a function of frequency, was a further few percent of that,” Kono said. “It took many hours to take reliable data at each temperature to average over many, many measurements, and it was necessary to take data at many, many temperatures to prove the existence of scaling.

    “Xinwei was very, very patient and persistent,” Kono said. “In addition, he carefully processed the huge amounts of data he collected to unfold the scaling law, which was really fascinating to me.”

    Making the films was even more challenging. To grow them thin enough to pass terahertz rays, the TU Wien team developed a unique molecular beam epitaxy system and an elaborate growth procedure. Ytterbium, rhodium and silicon were simultaneously evaporated from separate sources in the exact 1-2-2 ratio. Because of the high energy needed to evaporate rhodium and silicon, the system required a custom-made ultrahigh vacuum chamber with two electron-beam evaporators.

    “Our wild card was finding the perfect substrate: germanium,” said TU Wien graduate student Lukas Prochaska, a study co-lead author. The germanium was transparent to terahertz, and had “certain atomic distances (that were) practically identical to those between the ytterbium atoms in YbRh2Si2, which explains the excellent quality of the films,” he said.

    Si recalled discussing the experiment with Bühler-Paschen more than 15 years ago when they were exploring the means to test a new class of quantum critical point. The hallmark of the quantum critical point that they were advancing with co-workers is that the quantum entanglement between spins and charges is critical.

    Former Rice University graduate student Xinwei Li (left) and Professor Junichiro Kono in 2016 with the terahertz spectrometer Li used to measure quantum entanglement in YbRh2Si2. (Photo by Jeff Fitlow/Rice University)

    “At a magnetic quantum critical point, conventional wisdom dictates that only the spin sector will be critical,” he said. “But if the charge and spin sectors are quantum-entangled, the charge sector will end up being critical as well.”

    At the time, the technology was not available to test the hypothesis, but by 2016, the situation had changed. TU Wien could grow the films, Rice had recently installed a powerful microscope that could scan them for defects, and Kono had the terahertz spectrometer to measure optical conductivity. During Bühler-Paschen’s sabbatical visit to Rice that year, she, Si, Kono and Rice microscopy expert Emilie Ringe received support to pursue the project via an Interdisciplinary Excellence Award from Rice’s newly established Creative Ventures program.

    “Conceptually, it was really a dream experiment,” Si said. “Probe the charge sector at the magnetic quantum critical point to see whether it’s critical, whether it has dynamical scaling. If you don’t see anything that’s collective, that’s scaling, the critical point has to belong to some textbook type of description. But, if you see something singular, which in fact we did, then it is very direct and new evidence for the quantum entanglement nature of quantum criticality.”

    Si said all the efforts that went into the study were well worth it, because the findings have far-reaching implications.

    “Quantum entanglement is the basis for storage and processing of quantum information,” Si said. “At the same time, quantum criticality is believed to drive high-temperature superconductivity. So our findings suggest that the same underlying physics — quantum criticality — can lead to a platform for both quantum information and high-temperature superconductivity. When one contemplates that possibility, one cannot help but marvel at the wonder of nature.”

    Si is the Harry C. and Olga K. Wiess Professor in Rice’s Department of Physics and Astronomy. Kono is a professor in Rice’s departments of Electrical and Computer Engineering, Physics and Astronomy, and Materials Science and NanoEngineering and the director of Rice’s Applied Physics Graduate Program. Ringe is now at the University of Cambridge.

    Additional co-authors include Maxwell Andrews, Maximilian Bonta, Werner Schrenk, Andreas Limbeck and Gottfried Strasser, all of the TU Wien; Hermann Detz, formerly of TU Wien and currently at Brno University; Elisabeth Bianco, formerly of Rice and currently at Cornell University; Sadegh Yazdi, formerly of Rice and currently at the University of Colorado Boulder; and co-lead author Donald MacFarland, formerly of TU Wien and currently at the University at Buffalo.

    The research was supported by the European Research Council, the Army Research Office, the Austrian Science Fund, the European Union’s Horizon 2020 program, the National Science Foundation, the Robert A. Welch Foundation, Los Alamos National Laboratory and Rice University.

    RCQM leverages global partnerships and the strengths of more than 20 Rice research groups to address questions related to quantum materials. RCQM is supported by Rice’s offices of the provost and the vice provost for research, the Wiess School of Natural Sciences, the Brown School of Engineering, the Smalley-Curl Institute and the departments of Physics and Astronomy, Electrical and Computer Engineering, and Materials Science and NanoEngineering.

    See the full article here .


    Stem Education Coalition

    Rice U campus

    In his 1912 inaugural address, Rice University president Edgar Odell Lovett set forth an ambitious vision for a great research university in Houston, Texas; one dedicated to excellence across the range of human endeavor. With this bold beginning in mind, and with Rice’s centennial approaching, it is time to ask again what we aspire to in a dynamic and shrinking world in which education and the production of knowledge will play an even greater role. What shall our vision be for Rice as we prepare for its second century, and how ought we to advance over the next decade?

    This was the fundamental question posed in the Call to Conversation, a document released to the Rice community in summer 2005. The Call to Conversation asked us to reexamine many aspects of our enterprise, from our fundamental mission and aspirations to the manner in which we define and achieve excellence. It identified the pressures of a constantly changing and increasingly competitive landscape; it asked us to assess honestly Rice’s comparative strengths and weaknesses; and it called on us to define strategic priorities for the future, an effort that will be a focus of the next phase of this process.

  • richardmitnick 10:07 am on January 15, 2020 Permalink | Reply
    Tags: "Galactic gamma-ray sources reveal birthplaces of high-energy particles", , , Joint US-Mexico-European HAWC Observatory, , , Physics,   

    From Los Alamos National Laboratory: “Galactic gamma-ray sources reveal birthplaces of high-energy particles” 

    LANL bloc

    From Los Alamos National Laboratory

    Jan. 14, 2020
    ames Riordon
    Communications Office
    (505) 667-3272

    Researchers with the joint US-Mexico-European HAWC Observatory have identified a host of galactic sources of super-high-energy gamma rays.

    HAWC High Altitude Čerenkov Experiment, a
    US Mexico Europe collaboration located on the flanks of the Sierra Negra volcano in the Mexican state of Puebla at an altitude of 4100 meters(13,500ft), at WikiMiniAtlas 18°59′41″N 97°18′30.6″W. searches for cosmic rays

    A map of the galactic plane indicates the highest energy gamma ray sources yet discovered. The sources comprise a new catalog compiled by the members of the High Altitude Water Čerenkov Observatory collaboration.

    Nine sources of extremely high-energy gamma rays comprise a new catalog compiled by researchers with the High-Altitude Water Čerenkov (HAWC) Gamma-Ray Observatory. All produce gamma rays with energies over 56 trillion electron volts (TeV) and three emit gamma rays extending to 100 TeV and beyond, making these the highest-energy sources ever observed in our galaxy. The catalog helps to explain where the particles originate and how they are accelerated to such extremes.

    “The Earth is constantly being bombarded with charged particles called cosmic rays, but because they are charged, they bend in magnetic fields and don’t point back to their sources. We rely on gamma rays, which are produced close to the sources of the cosmic rays, to narrow down their origins,” said Kelly Malone, an astrophysicist in the Neutron Science and Technology group at Los Alamos National Laboratory and a member of the HAWC scientific collaboration. “There are still many unanswered questions about cosmic-ray origins and acceleration. High energy gamma rays are produced near cosmic-ray sites and can be used to probe cosmic-ray acceleration. However, there is some ambiguity in using gamma rays to study this, as high-energy gamma rays can also be produced via other mechanisms, such as lower-energy photons scattering off of electrons, which commonly occurs near pulsars.”

    Newly Discovered Gamma Ray Sources Have the Highest Energy Ever Recorded.

    The newly cataloged astrophysical gamma-ray sources have energies about 10 times higher than can be produced using experimental particle colliders on Earth. While higher-energy astrophysical particles have been previously detected, this is the first time specific galactic sources have been pinpointed. All of the sources have extremely energetic pulsars (highly magnetized rotating neutron stars) nearby. The number of sources detected may indicate that ultra-high-energy emission is a generic feature of powerful particle winds coming from pulsars embedded in interstellar gas clouds known as nebulae, and that more detections will be forthcoming.

    The HAWC Gamma-Ray Observatory consists of an array of water-filled tanks sitting high on the slopes of the Sierra Negra volcano in Puebla, Mexico, where the atmosphere is thin and offers better conditions for observing gamma rays. When these gamma rays strike molecules in the atmosphere they produce showers of energetic particles. Although nothing can travel faster than the speed of light in a vacuum, light moves more slowly through water. As a result, some particles in cosmic ray showers travel faster than light in the water inside the HAWC detector tanks. The faster-than-light particles, in turn, produce characteristic flashes of light called Čerenkov radiation. By recording the Čerenkov flashes in the HAWC water tanks, researchers can reconstruct the sources of the particle showers to learn about the particles that caused them in the first place.

    The HAWC collaborators plan to continue searching for the sources of high-energy cosmic rays. By combining their data with measurements from other types of observatories such as neutrino, x-ray, radio and optical telescopes, they hope to disentangle the astrophysical mechanisms that produce the cosmic rays that continuously rain down on our planet.

    Science paper:
    Multiple Galactic Sources with Emission Above 56 TeV Detected by HAWC
    Physical Review Letters

    See the full article here .


    Please help promote STEM in your local schools.

    Stem Education Coalition

    Los Alamos National Laboratory’s mission is to solve national security challenges through scientific excellence.

    LANL campus

    Los Alamos National Laboratory, a multidisciplinary research institution engaged in strategic science on behalf of national security, is operated by Los Alamos National Security, LLC, a team composed of Bechtel National, the University of California, The Babcock & Wilcox Company, and URS for the Department of Energy’s National Nuclear Security Administration.

    Los Alamos enhances national security by ensuring the safety and reliability of the U.S. nuclear stockpile, developing technologies to reduce threats from weapons of mass destruction, and solving problems related to energy, environment, infrastructure, health, and global security concerns.

    Operated by Los Alamos National Security, LLC for the U.S. Dept. of Energy’s NNSA

  • richardmitnick 5:32 pm on January 14, 2020 Permalink | Reply
    Tags: ANTARES, , , , Physics,   

    From U Wisconsin IceCube Collaboration and ANTARES: “ANTARES and IceCube combine forces to search for southern sky neutrino sources” 

    U Wisconsin ICECUBE neutrino detector at the South Pole

    From From U Wisconsin IceCube Collaboration

    14 Jan 2020
    Madeleine O’Keefe

    Teamwork makes the dream work. Especially when that dream is to find sources of elusive particles called neutrinos.

    Neutrinos are chargeless, nearly massless subatomic particles. These elusive particles are abundantly produced in nuclear fusion processes in our sun or the natural radioactivity of Earth. In rare cases, we also observe high-energy neutrinos from outer space, known as astrophysical neutrinos. They fly through light-years of space at close to the speed of light without being tugged around by magnetic fields or other forces; this makes them ideal astronomical messengers, as they bring us information from the most enigmatic objects in the cosmos. But we still don’t know where they originate.

    The IceCube Neutrino Observatory in Antarctica is one experiment looking for sources of these enigmatic particles. IceCube does this with an array of 5,160 optical detectors buried in a cubic kilometer of South Pole ice; when a neutrino from outer space reaches Antarctica with enough energy, it can hit an atom in the ice and produce another particle that flies through IceCube, trailed by a cone of light called Čerenkov radiation. That cone of light triggers the detectors it passes, leaving clusters of lit-up detectors behind it.

    Meanwhile, floating in the Mediterranean Sea is a similar neutrino experiment called ANTARES.


    The IceCube Collaboration recently conducted a combined IceCube-ANTARES search for neutrino point-like and extended sources in the southern sky. They didn’t find any significant evidence for cosmic neutrino sources, but the analysis shows the strong potential for combining data sets from both experiments. Their results were recently submitted to The Astrophysical Journal.

    This sky map shows the result of the search for point-like sources in the whole southern sky. Higher values of -log10(p-value) indicate more significant directions. The red contour shows the position of the most significant cluster of events, which was not significant enough to be considered a source. Credit: IceCube Collaboration

    It’s an exciting time for neutrino astronomy. IceCube’s past few years of research have yielded promising results, including the discovery of the first evidence of neutrinos coming from an astrophysical source. But the origins of most of the astrophysical neutrinos that reach Earth remain unknown.

    So researchers around the world are continuing to look for neutrino sources. Giulia Illuminati of the Instituto de Física Corpuscular in Valencia, Spain, led this search, which combined data sets from IceCube and ANTARES.

    “The motivation behind this analysis lies in the fact that ANTARES and IceCube, thanks to their different sizes and locations, complement each other when looking for neutrino sources in the southern sky,” she says.

    ANTARES’s location in the Mediterranean results in a lower background for neutrino source hunting in the Southern Hemisphere, while IceCube’s larger size gives it a higher detection capability. Together, these characteristics mean an increased chance to detect sources of astrophysical neutrinos in the southern sky.

    Illuminati and her collaborators performed five types of searches for point-like and extended sources of astrophysical neutrinos using ANTARES and IceCube data. (Technically, all neutrino sources are “extended,” but when they appear on the celestial sphere with a size smaller than IceCube’s angular resolution, they cannot be resolved and are called “point-like.”)

    In the first two searches, they scanned the full southern sky and a restricted region around the Galactic Center to look for significant emission of cosmic neutrinos from point-like and extended sources. In the third search, they investigated the positions of 57 astrophysical objects in a predefined list of candidate point-like emitters of high-energy neutrinos. Finally, they performed dedicated searches at the locations of two promising neutrino source candidates: the supermassive black hole Sagittarius A* and the shell-type supernova remnant RXJ 1713.7-3946.

    Ultimately, they did not find any significant point-like or extended neutrino emission, but they derived upper limits on the neutrino flux from the various analyzed sources. Even without a significant discovery, this analysis proved the high potential of joint searches for neutrino sources with ANTARES and IceCube. By combining the data sets of the two detectors, the researchers were able to improve the sensitivity in different regions of the southern sky by about a factor of 2 compared to individual analyses.

    “These results strongly motivate a joint analysis of future data sets, not only of the ANTARES and the IceCube telescopes but also of the future detectors KM3NeT and IceCube-Gen2 [below],” says Illuminati.

    KM3NeT Digital Optical Module (DOM) in the laboratory .www.km3net.org

    Artist’s expression of the KM3NeT neutrino telescope

    It relies on the same principle as IceCube: It’s another three-dimensional array of optical detectors in a transparent medium (here, water instead of ice). If a high-energy neutrino hits an atom in the water, it will produce a particle and Cherenkov light that triggers the optical modules in the sea.

    The IceCube Collaboration recently conducted a combined IceCube-ANTARES search for neutrino point-like and extended sources in the southern sky. They didn’t find any significant evidence for cosmic neutrino sources, but the analysis shows the strong potential for combining data sets from both experiments. Their results were recently submitted to The Astrophysical Journal.

    See the full article here .


    Please help promote STEM in your local schools.

    Stem Education Coalition
    IceCube is a particle detector at the South Pole that records the interactions of a nearly massless sub-atomic particle called the neutrino. IceCube searches for neutrinos from the most violent astrophysical sources: events like exploding stars, gamma ray bursts, and cataclysmic phenomena involving black holes and neutron stars. The IceCube telescope is a powerful tool to search for dark matter, and could reveal the new physical processes associated with the enigmatic origin of the highest energy particles in nature. In addition, exploring the background of neutrinos produced in the atmosphere, IceCube studies the neutrinos themselves; their energies far exceed those produced by accelerator beams. IceCube is the world’s largest neutrino detector, encompassing a cubic kilometer of ice.

    IceCube employs more than 5000 detectors lowered on 86 strings into almost 100 holes in the Antarctic ice NSF B. Gudbjartsson, IceCube Collaboration

    Lunar Icecube

    IceCube DeepCore annotated

    IceCube PINGU annotated

    DM-Ice II at IceCube annotated

  • richardmitnick 3:29 pm on January 14, 2020 Permalink | Reply
    Tags: , , , , , Dilepton channel, Drell–Yan process, , Physics, Searching for new physics in the TeV regime by looking for the decays of new particles., The dark photon (Zd)?   

    From CERN Courier: “CMS goes scouting for dark photons” 

    From CERN Courier

    6 December 2019
    A report from the CMS experiment

    One of the best strategies for searching for new physics in the TeV regime is to look for the decays of new particles. The CMS collaboration has searched in the dilepton channel for particles with masses above a few hundred GeV since the start of LHC data taking. Thanks to newly developed triggers, the searches are now being extended to the more difficult lower range of masses. A promising possible addition to the Standard Model (SM) that could exist in this mass range is the dark photon (Zd). Its coupling with SM particles and production rate depend on the value of a kinetic mixing coefficient ε, and the resulting strength of the interaction of the Zd with ordinary matter may be several orders of magnitude weaker than the electroweak interaction.

    The CMS collaboration has recently presented results of a search for a narrow resonance decaying to a pair of muons in the mass range from 11.5 to 200 GeV. This search looks for a strikingly sharp peak on top of a smooth dimuon mass spectrum that arises mainly from the Drell–Yan process. At masses below approximately 40 GeV, conventional triggers are the main limitation for this analysis as the thresholds on the muon transverse momenta (pT), which are applied online to reduce the rate of events saved for offline analysis, introduce a significant kinematic acceptance loss, as evident from the red curve in figure 1.

    Fig. 1. Dimuon invariant-mass distributions obtained from data collected by the standard dimuon triggers (red) and the dimuon scouting triggers (green).

    A dedicated set of high-rate dimuon “scouting” triggers, with some additional kinematic constraints on the dimuon system and significantly lower muon pT thresholds, was deployed during Run 2 to overcome this limitation. Only a minimal amount of high-level information from the online reconstruction is stored for the selected events. The reduced event size allows significantly higher trigger rates, up to two orders of magnitude higher than the standard muon triggers. The green curve in figure 1 shows the dimuon invariant mass distribution obtained from data collected with the scouting triggers. The increase in kinematic acceptance for low masses can be well appreciated.

    The full data sets collected with the muon scouting and standard dimuon triggers during Run 2 are used to probe masses below 45 GeV, and between 45 and 200 GeV, respectively, excluding the mass range from 75 to 110 GeV where Z-boson production dominates. No significant resonant peaks are observed, and limits are set on ε2 at 90% confidence as a function of the ZD mass (figure 2). These are among the world’s most stringent constraints on dark photons in this mass range.

    Fig. 2. Upper limits on ε2 as a function of the ZD mass. Results obtained with data collected by the dimuon scouting triggers are to the left of the dashed line. Constraints from measurement of the electroweak observables are shown in light blue.

    See the full article here .

    Please help promote STEM in your local schools.

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    CERN/ATLAS detector


    CERN/ALICE Detector

    CERN CMS New

    CERN LHCb New II


    CERN map

    CERN LHC Grand Tunnel

    CERN LHC particles

  • richardmitnick 11:55 am on January 14, 2020 Permalink | Reply
    Tags: "A voyage to the heart of the neutrino", , , , , , Physics, SNOLAB- a Canadian underground physics laboratory at a depth of 2 km in Vale's Creighton nickel mine in Sudbury Ontario Canada., Super-Kamiokande experiment located under Mount Ikeno near the city of Hida Gifu Prefecture Japan, The Karlsruhe Tritium Neutrino (KATRIN) experiment, The most abundant particles in the universe besides photons., The three neutrino mass eigenstates, We know now that the three neutrino flavour states we observe in experiments – νe; νμ; and ντ – are mixtures of three neutrino mass states.   

    From CERN Courier: “A voyage to the heart of the neutrino” 

    From CERN Courier

    10 January 2020

    The Karlsruhe Tritium Neutrino (KATRIN) experiment has begun its seven-year-long programme to determine the absolute value of the neutrino mass.

    KATRIN experiment aims to measure the mass of the neutrino using a huge device called a spectrometer (interior shown)Karlsruhe Institute of Technology, Germany

    On 11 June 2018, a tense silence filled the large lecture hall of the Karlsruhe Institute of Technology (KIT) in Germany.


    Karlsruhe Institute Of Technology (KIT)

    Karlsruhe Institute of Technology (KIT) in Germany.

    In front of an audience of more than 250 people, 15 red buttons were pressed simultaneously by a panel of senior figures including recent Nobel laureates Takaaki Kajita and Art McDonald. At the same time, operators in the control room of the Karlsruhe Tritium Neutrino (KATRIN) experiment lowered the retardation voltage of the apparatus so that the first beta electrons were able to pass into KATRIN’s giant spectrometer vessel. Great applause erupted when the first beta electrons hit the detector.

    In the long history of measuring the tritium beta-decay spectrum to determine the neutrino mass, the ensuing weeks of KATRIN’s first data-taking opened a new chapter. Everything worked as expected, and KATRIN’s initial measurements have already propelled it into the top ranks of neutrino experiments. The aim of this ultra-high-precision beta-decay spectroscope, more than 15 years in the making, is to determine, by the mid-2020s, the absolute mass of the neutrino.

    Massive discovery

    Since the discovery of the oscillation of atmospheric neutrinos by the Super-Kamiokande experiment in 1998, and of the flavour transitions of solar neutrinos by the SNO experiment shortly afterwards, it was strongly implied that neutrino masses are not zero, but big enough to cause interference between distinct mass eigenstates as a neutrino wavepacket evolves in time. We know now that the three neutrino flavour states we observe in experiments – νe, νμ and ντ – are mixtures of three neutrino mass states.

    Super-Kamiokande experiment. located under Mount Ikeno near the city of Hida, Gifu Prefecture, Japan

    SNOLAB, a Canadian underground physics laboratory at a depth of 2 km in Vale’s Creighton nickel mine in Sudbury, Ontario

    SNOLAB, Sudbury, Ontario, Canada.

    Though not massless, neutrinos are exceedingly light. Previous experiments designed to directly measure the scale of neutrino masses in Mainz and Troitsk produced an upper limit of 2 eV for the neutrino mass – a factor 250,000 times smaller than the mass of the otherwise lightest massive elementary particle, the electron. Nevertheless, neutrino masses are extremely important for cosmology as well as for particle physics. They have a number density of around 336 cm–3, making them the most abundant particles in the universe besides photons, and therefore play a distinct role in the formation of cosmic structure. Comparing data from the Planck satellite together with data from galaxy surveys (baryonic acoustic oscillations) with simulations of the evolution of structure yields an upper limit on the sum of all three neutrino masses of 0.12 eV at 95% confidence within the framework of the standard Lambda cold-dark matter (ΛCDM) cosmological model.

    Lamda Cold Dark Matter Accerated Expansion of The universe http scinotions.com the-cosmic-inflation-suggests-the-existence-of-parallel-universes
    Alex Mittelmann, Coldcreation

    Considerations of “naturalness” lead most theorists to speculate that the exceedingly tiny neutrino masses do not arise from standard Yukawa couplings to the Higgs boson, as per the other fermions, but are generated by a different mass mechanism. Since neutrinos are electrically neutral, they could be identical to their antiparticles, making them Majorana particles. Via the so-called seesaw mechanism, this interesting scenario would require a new and very high particle mass scale to balance the smallness of the neutrino masses, which would be unreachable with present accelerators.

    Inner space KATRIN’s main spectrometer, the largest ultra-high-vacuum vessel in the world, contains a dual-layer electrode system comprising 23,000 wires to shield the inner volume from charged particles. Credit: KATRIN

    As neutrino oscillations arise due to interference between mass eigenstates, neutrino-oscillation experiments are only able to determine splittings between the squares of the neutrino mass eigenstates. Three experimental avenues are currently being pursued to determine the neutrino mass. The most stringent upper limit is currently the model-dependent bound set by cosmological data, as already mentioned, which is valid within the ΛCDM model. A second approach is to search for neutrinoless double-beta decay, which allows a statement to be made about the size of the neutrino masses but presupposes the Majorana nature of neutrinos.

    U Washington Majorana Demonstrator Experiment at SURF

    The third approach – the one adopted by KATRIN – is the direct determination of the neutrino mass from the kinematics of a weak process such as beta decay, which is completely model-independent and depends only on the principle of energy and momentum conservation.

    Fig. 1. The beta spectrum of tritium (left), showing in detail the effect of different neutrino masses on the endpoint (right). Credit: CERN

    The direct determination of the neutrino mass relies on the precise measurement of the shape of the beta electron spectrum near the endpoint, which is governed by the available phase space (figure 1). This spectral shape is altered by the neutrino mass value: the smaller the mass, the smaller the spectral modification. One would expect to see three modifications, one for each neutrino mass eigenstate. However, due to the tiny neutrino mass differences, a weighted sum is observed. This “average electron neutrino mass” is formed by the incoherent sum of the squares of the three neutrino mass eigenstates, which contribute to the electron neutrino according to the PMNS neutrino-mixing matrix. The super-heavy hydrogen isotope tritium is ideal for this purpose because it combines a very low endpoint energy, Eo, of 18.6 keV and a short half-life of 12.3 years with a simple nuclear and atomic structure.

    KATRIN is born

    Around the turn of the millennium, motivated by the neutrino oscillation results, Ernst Otten of the University of Mainz and Vladimir Lobashev of INR Troitsk proposed a new, much more sensitive experiment to measure the neutrino mass from tritium beta decay. To this end, the best methods from the previous experiments in Mainz, Troitsk and Los Alamos were to be combined and upscaled by up to two orders of magnitude in size and precision. Together with new technologies and ideas, such as laser Raman spectroscopy or active background reduction methods, the apparatus would increase the sensitivity to the observable in beta decay (the square of the electron antineutrino mass) by a factor of 100, resulting in a neutrino-mass sensitivity of 0.2 eV. Accordingly, the entire experiment was designed to the limits of what was feasible and even beyond (see “Technology transfer delivers ultimate precision” box).

    Precise The electron transport and tritium retention system. Credit: KIT

    Many technologies had to be pushed to the limits of what was feasible or even beyond. KATRIN became a CERN-recognised experiment (RE14) in 2007 and the collaboration worked with CERN experts in many areas to achieve this. The KATRIN main spectrometer is the largest ultra-high vacuum vessel in the world, with a residual gas pressure in the range of 10–11 mbar – a pressure that is otherwise only found in large volumes inside the LHC ring – equivalent to the pressure recorded at the lunar surface.

    Even though the inner surface was instrumented with a complex dual-layer wire electrode system for background suppression and electric-field shaping, this extreme vacuum was made possible by rigorous material selection and treatment in addition to non-evaporable getter technology developed at CERN. KATRIN’s almost 40 m-long chain of superconducting magnets with two large chicanes was put into operation with the help of former CERN experts, and a 223Ra source was produced at ISOLDE for background studies at KATRIN.

    CERN ISOLDE Looking down into the ISOLDE experimental hall

    A series of 83mKr conversion electron sources based on implanted 83Rb for calibration purposes was initially produced at ISOLDE. At present these are produced by KATRIN collaborators and further developed with regard to line stability.

    Conversely, the KATRIN collaboration has returned its knowledge and methods to the community. For example, the ISOLDE high-voltage system was calibrated twice with the ppm-accuracy KATRIN voltage dividers, and the magnetic and electrical field calculation and tracking programme KASSIOPEIA developed by KATRIN was published as open source and has become the standard for low-energy precision experiments. The fast and precise laser Raman spectroscopy developed for KATRIN is also being applied to fusion technology.

    KIT was soon identified as the best place for such an experiment, as it had the necessary experience and infrastructure with the Tritium Laboratory Karlsruhe. The KIT board of directors quickly took up this proposal and a small international working group started to develop the project. At a workshop at Bad Liebenzell in the Black Forest in January 2001, the project received so much international support that KIT, together with nearly all the groups from the previous neutrino-mass experiments, founded the KATRIN collaboration. Currently, the 150-strong KATRIN collaboration comprises 20 institutes from six countries.

    It took almost 16 years from the first design to complete KATRIN, largely because many new technologies had to be developed, such as a novel concept to limit the temperature fluctuations of the huge tritium source to the mK scale at 30 K or the high-voltage stabilisation and calibration to the 10 mV scale at 18.6 kV. The experiment’s two most important and also most complex components are the gaseous, windowless molecular tritium source (WGTS) and the very large spectrometer. In the WGTS, tritium gas is introduced in the midpoint of the 10 m-long beam tube, where it flows out to both sides to be pumped out again by turbomolecular pumps. After being partially cleaned it is re-injected, yielding a closed tritium cycle. This results in an almost opaque column density with a total decay rate of 1011 per second. The beta electrons are guided adiabatically to a tandem of a pre- and a main spectrometer by superconducting magnets of up to 6 T. Along the way, differential and cryogenic pumping sections including geometric chicanes reduce the tritium flow by more than 14 orders of magnitude to keep the spectrometers free of tritium (figure 2).

    Fig. 2. The 70 m-long KATRIN setup showing the key stages and components. Credit: CERN

    The KATRIN spectrometers operate as so-called MAC-E filters, whereby electrons are guided by two superconducting solenoids at either end and their momenta are collimated by the magnetic field gradient. This “magnetic bottle” effect transforms almost all kinetic energy into longitudinal energy, which is filtered by an electrostatic retardation potential so that only electrons with enough energy to overcome the barrier are able to pass through. The smaller pre-spectrometer blocks the low-energy part of the beta spectrum (which carries no information on the neutrino mass), while the 10 m-diameter main spectrometer provides a much sharper filter width due to its huge size.

    The transmitted electrons are detected by a high-resolution segmented silicon detector. By varying the retarding potential of the main spectrometer, a narrow region of the beta spectrum of several tens of eV below the endpoint is scanned, where the imprint of a non-zero neutrino mass is maximal. Since the relative fraction of the tritium beta spectrum in the last 1 eV below the endpoints amounts to just 2 × 10–13, KATRIN demands a tritium source of the highest intensity. Of equal importance is the high precision needed to understand the measured beta spectrum. Therefore, KATRIN possesses a complex calibration and monitoring system to determine all systematics with the highest precision in situ, e.g. the source strength, the inelastic scattering of beta electrons in the tritium source, the retardation voltage and the work functions of the tritium source and the main spectrometer.

    Start-up and beyond

    After intense periods of commissioning during 2018, the tritium source activity was increased from its initial value of 0.5 GBq (which was used for the inauguration measurements) to 25 GBq (approximately 22% of nominal activity) in spring 2019. By April, the first KATRIN science run had begun and everything went like clockwork. The decisive source parameters – temperature, inlet pressure and tritium content – allowed excellent data to be taken, and the collaboration worked in several independent teams to analyse these data. The critical systematic uncertainties were determined both by Monte Carlo propagation and with the covariance-matrix method, and the analyses were also blinded so as not to generate bias. The excitement during the un-blinding process was huge within the KATRIN collaboration, which gathered for this special event, and relief spread when the result became known. The neutrino-mass square turned out to be compatible with zero within its uncertainty budget. The model fits the data very well (figure 3) and the fitted endpoint turned out to be compatible with the mass difference between 3He and tritium measured in Penning traps. The new results were presented at the international TAUP 2019 conference in Toyama, Japan, and have recently been published.

    Fig. 3. The beta-electron spectrum in the vicinity of its endpoint with 50 times enlarged error bars and a best-fit model (top) and fit residuals (bottom). Credit: CERN

    This first result shows that all aspects of the KATRIN experiment, from hardware to data-acquisition to analysis, works as expected. The statistical uncertainty of the first KATRIN result is already smaller by a factor of two compared to previous experiments and systematic uncertainties have gone down by a factor of six. A neutrino mass was not yet extracted with these first four weeks of data, but an upper limit for the neutrino mass of 1.1 eV (90% confidence) can be drawn, catapulting KATRIN directly to the top of the world of direct neutrino-mass experiments. In the mass region around 1 eV, the limit corresponds to the quasi-degenerated neutrino-mass range where the mass splittings implied by neutrino-oscillation experiments are negligible compared to the absolute masses.

    The neutrino-mass result from KATRIN is complementary to results obtained from searches for neutrinoless double beta decay, which are sensitive to the “coherent sum” mββ of all neutrino mass eigenstates contributing to the electron neutrino. Apart from additional phases that can lead to possible cancellations in this sum, the values of the nuclear matrix elements that need to be calculated to connect the neutrino mass mββ with the observable (the half-life) still possess uncertainties of a factor two. Therefore, the result from a direct neutrino-mass determination is more closely connected to results from cosmological data, which give (model-dependent) access to the neutrino-mass sum.

    A sizeable influence

    Currently, KATRIN is taking more data and has already increased the source activity by a factor of four to close to its design value. The background rate is still a challenge. Various measures, such as out-baking and using liquid-nitrogen cooled baffles in front of the getter pumps, have already yielded a background reduction by a factor 10, and more will be implemented in the next few years. For the final KATRIN sensitivity of 0.2 eV (90% confidence) on the absolute neutrino-mass scale, a total of 1000 days of data are required. With this sensitivity KATRIN will either find the neutrino mass or will set a stringent upper limit. The former would confront standard cosmology, while the latter would exclude quasi-degenerate neutrino masses and a sizeable influence of neutrinos on the formation of structure in the universe. This will be augmented by searches for physics beyond the Standard Model, such as for sterile neutrino admixtures with masses from the eV to the keV scale.

    Standard Model of Particle Physics

    Neutrino-oscillation results yield a lower limit for the effective electron-neutrino mass to manifest in direct neutrino-mass experiments of about 10 meV (50 meV) for normal (inverse) mass ordering. Therefore, many plans exist to cover this region in the future. At KATRIN, there is a strong R&D programme to upgrade the MAC-E filter principle from the current integral to a differential read-out, which will allow a factor-of-two improvement in sensitivity on the neutrino mass. New approaches to determine the absolute neutrino-mass scale are also being developed: Project 8, a radio-spectroscopy method to eventually be applied to an atomic tritium source; and the electron-capture experiments ECHo and HOLMES, which intend to deploy large arrays of cryogenic bolometers with the implanted isotope 163Ho. In parallel, the next generation of neutrinoless double beta decay experiments like LEGEND, CUPID or nEXO (as well as future xenon-based dark-matter experiments) aim to cover the full range of inverted neutrino-mass ordering. Finally, refined cosmological data should allow us to probe the same mass region (and beyond) within the next decades, while long-baseline neutrino-oscillation experiments, such as JUNO, DUNE and Hyper-Kamiokande, will probe the neutrino-mass ordering implemented in nature. As a result of this broad programme for the 2020s, the elusive neutrino should finally yield some of its secrets and inner properties beyond mixing.

    See the full article here .

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    CERN/ATLAS detector


    CERN/ALICE Detector

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  • richardmitnick 11:29 am on January 12, 2020 Permalink | Reply
    Tags: A novel type of detector that enables the oscillation profile of light waves to be precisely determined., , Laboratory for Attosecond Physics at Ludwig-Maximilians-Universitaet, , , , Physics   

    Max Planck Institute of Quantum Optics via phys.org: “Laser physics- At the pulse of a light wave” 

    Max Planck Institute of Quantum Optics

    Max Planck Institute of Quantum Optics



    January 10, 2020
    Ludwig Maximilian University of Munich

    How a novel type of detector enables the oscillation profile of light waves to be precisely determined. Credit: Philipp Rosenberger

    Physicists in the Laboratory for Attosecond Physics at Ludwig-Maximilians-Universitaet (LMU) in Munich and at the Max Planck Institute for Quantum Optics (MPQ) have developed a novel type of detector that enables the oscillation profile of light waves to be precisely determined.

    Light is hard to get a hold on. Light waves propagate with a velocity of almost 300,000 km per second, and the wavefront oscillates several hundred trillion times in that same interval. In the case of visible light, the physical distance between successive peaks of the light wave is less than 1 micrometer, and peaks are separated in time by less than 3 millionths of a billionth of a second (< 3 femtoseconds). To work with light, one must control it—and that requires precise knowledge of its behaviour. It may even be necessary to know the exact position of the crests or valleys of the light wave at a given instant. Researchers based at the Laboratory for Attosecond Physics (LAP) at the LMU Munich and the Max Planck Institute for Quantum Optics are now in a position to measure the exact location of such peaks within single ultrashort pulses of infrared light with the aid of a newly developed detector.

    Such pulses, which encompass only a few oscillations of the wave, can be used to investigate the behaviour of molecules and their constituent atoms, and the new detector is a very valuable tool in this context. Ultrashort laser pulses allow scientists to study dynamic processes at molecular and even subatomic levels. Using trains of these pulses, it is possible first to excite the target particles and then to film their responses in real time. In intense light fields, however, it is crucial to know the precise waveform of the pulses. Since the peak of the oscillating (carrier) light field and that of the pulse envelope can shift with respect to each other between different laser pulses, it is important to know the precise waveform of each pulse.

    The team at LAP, which was led by Dr. Boris Bergues and Professor Matthias Kling, head of the Ultrafast Imaging and Nanophotonics Group, has now made a decisive breakthrough in the characterization of light waves. Their new detector allows them to determine the 'phase," i.e. the precise positions of the peaks of the few oscillation cycles within each and every pulse, at repetition rates of 10,000 pulses per second. To do so, the group generated circularly polarized laser pulses in which the orientation of the propagating optical field rotates like a clock hand, and then focused the rotating pulse in ambient air.

    The interaction between the pulse and molecules in the air results in a short burst of electric current, whose direction depends on the position of the peak of the light wave. By analyzing the exact direction of the current pulse, the researchers were able to retrieve the phase of the 'carrier-envelope offset," and thus reconstruct the form of the light wave. Unlike the method conventionally employed for phase determination, which requires the use of a complex vacuum apparatus, the new technique works in ambient air and the measurements require very few extra components. "The simplicity of the setup is likely to ensure that it will become a standard tool in laser technology," explains Matthias Kling.

    “We believe that this technique can also be applied to lasers with much higher repetition rates and in different spectral regions”; says Boris Bergues.”Our methodology is of particular interest in the context of the characterization of extremely short laser pulses with high repetition rates, such as those generated at Europe’s Extreme Light Infrastructure (ELI)” adds Prof. Matthias Kling. When applied to the latest sources of ultrashort laser pulses, this new method of waveform analysis could pave the way to technological breakthroughs, as well as permitting new insights into the behaviour of elementary particles & in the fast lane.

    Science paper:
    Single-shot carrier–envelope-phase measurement in ambient air

    See the full article here .


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    About Science X in 100 words

    Science X™ is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004 (Physorg.com), Science X’s readership has grown steadily to include 5 million scientists, researchers, and engineers every month. Science X publishes approximately 200 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Science X community members enjoy access to many personalized features such as social networking, a personal home page set-up, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.
    Mission 12 reasons for reading daily news on Science X Organization Key editors and writersinclude 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

    Research at the Max Planck Institute of Quantum Optics
    Light can behave as an electromagnetic wave or a shower of particles that have no mass, called photons, depending on the conditions under which it is studied or used. Matter, on the other hand, is composed of particles, but it can actually exhibit wave-like properties, giving rise to many astonishing phenomena in the microcosm.

    At our institute we explore the interaction of light and quantum systems, exploiting the two extreme regimes of the wave-particle duality of light and matter. On the one hand we handle light at the single photon level where wave-interference phenomena differ from those of intense light beams. On the other hand, when cooling ensembles of massive particles down to extremely low temperatures we suddenly observe phenomena that go back to their wave-like nature. Furthermore, when dealing with ultrashort and highly intense light pulses comprising trillions of photons we can completely neglect the particle properties of light. We take advantage of the large force that the rapidly oscillating electromagnetic field exerts on electrons to steer their motion within molecules or accelerate them to relativistic energies.

  • richardmitnick 10:12 am on January 11, 2020 Permalink | Reply
    Tags: , Batchelor’s law, First Mathematical Proof for a Key Law of Turbulence in Fluid Mechanics, Navier-Stokes equations- which describe how fluids flow, Physics, University of Maryland Computer Mathematics and Natural Sciences   

    From University of Maryland Computer,Mathematics and Natural Sciences: “Researchers Develop First Mathematical Proof for a Key Law of Turbulence in Fluid Mechanics” 

    From University of Maryland Computer,Mathematics and Natural Sciences

    December 11, 2019

    Kimbra Cutlip

    University of Maryland mathematicians provide a mathematical explanation for a previously uncertain law of physics, revealing when the law applies and when it doesn’t.

    Mathematicians from UMD have developed the first rigorous proof for a fundamental law of turbulence. Batchelor’s law, which helps explain how chemical concentrations and temperature variations distribute themselves in a fluid, can be seen at work in the variously sized swirls of mixing warm and cold ocean water. Image Credit: NOAA/Geophysical Fluid Dynamics Laboratory

    What if engineers could design a better jet with mathematical equations that drastically reduce the need for experimental testing? Or what if weather prediction models could predict details in the movement of heat from the ocean into a hurricane? These things are impossible now, but could be possible in the future with a more complete mathematical understanding of the laws of turbulence.

    University of Maryland mathematicians Jacob Bedrossian, Samuel Punshon-Smith and Alex Blumenthal have developed the first rigorous mathematical proof explaining a fundamental law of turbulence. The proof of Batchelor’s law will be presented at a meeting of the Society for Industrial and Applied Mathematics on December 12, 2019.

    Although all laws of physics can be described using mathematical equations, many are not supported by detailed mathematical proofs that explain their underlying principles. One area of physics that has been considered too challenging to explain with rigorous mathematics is turbulence. Seen in ocean surf, billowing clouds and the wake behind a speeding vehicle, turbulence is the chaotic movement of fluids (including air and water) that includes seemingly random changes in pressure and velocity.

    Turbulence is the reason the Navier-Stokes equations, which describe how fluids flow, are so hard to solve that there is a million-dollar reward for anyone who can prove them mathematically. To understand fluid flow, scientists must first understand turbulence.

    “It should be possible to look at a physical system and understand mathematically if a given physical law is true,” said Jacob Bedrossian, a professor of mathematics at UMD and a co-author of the proof. “We believe our proof provides the foundation for understanding why Batchelor’s law, a key law of turbulence, is true in a way that no theoretical physics work has done so far. This work could help clarify some of the variations seen in turbulence experiments and predict the settings where Batchelor’s law applies as well as where it doesn’t.”

    Since its introduction in 1959, physicists have debated the validity and scope of Batchelor’s law, which helps explain how chemical concentrations and temperature variations distribute themselves in a fluid. For example, stirring cream into coffee creates a large swirl with small swirls branching off of it and even smaller ones branching off of those. As the cream mixes, the swirls grow smaller and the level of detail changes at each scale. Batchelor’s law predicts the detail of those swirls at different scales.

    The law plays a role in such things as chemicals mixing in a solution, river water blending with saltwater as it flows into the ocean and warm Gulfstream water combining with cooler water as it flows north. Over the years, many important contributions have been made to help understand this law, including work at UMD by Distinguished University Professors Thomas Antonsen and Edward Ott. However, a complete mathematical proof of Batchelor’s law has remained elusive.

    “Before the work of Professor Bedrossian and his co-authors, Batchelor’s law was a conjecture,” said Vladimir Sverak, a professor of mathematics at the University of Minnesota who was not involved in the work. “The conjecture was supported by some data from experiments, and one could speculate as to why such a law should hold. A mathematical proof of the law can be considered as an ideal consistency check. It also gives us a better understanding of what is really going on in the fluid, and this may lead to further progress.”

    “We weren’t sure if this could be done,” said Bedrossian, who also has a joint appointment in UMD’s Center for Scientific Computation and Mathematical Modeling. “The universal laws of turbulence were thought to be too complex to address mathematically. But we were able to crack the problem by combining expertise from multiple fields.”

    An expert in partial differential equations, Bedrossian brought in two UMD postdoctoral researchers who are experts in three other areas to help him solve the problem. Samuel Punshon-Smith (Ph.D. ’17, applied mathematics and statistics, and scientific computation), now the Prager Assistant Professor at Brown University, is an expert in probability. Alex Blumenthal is an expert in dynamical systems and ergodic theory, a branch of mathematics that includes what is commonly known as chaos theory. The team represented four distinct areas of mathematical expertise that rarely interact to this degree. All were essential to solving the problem.

    “The way the problem has been approached is indeed creative and innovative,” Sverak said. “Sometimes the method of proof can be even more important than the proof itself. It is likely that ideas from the papers by Professor Bedrossian and his co-authors will be very useful in future research.”

    The new level of collaboration that the team brought to this issue sets the stage for developing mathematical proofs to explain other unproven laws of turbulence.

    “If this proof is all we achieve, I think we’ve accomplished something,” Bedrossian said. “But I’m hopeful that this is a warmup and that this opens a door to saying ‘Yes, we can prove universality laws of turbulence and they are not beyond the realm of mathematics.’ Now that we are equipped with a much clearer understanding of how to use mathematics to study these questions, we are working to build the mathematical tools required to study more of these laws.”

    Understanding the underlying physical principles behind more laws of turbulence could eventually help engineers and physicists in designing better vehicles, wind turbines and similar technologies or in making better weather and climate predictions.


    The proof of Batchelor’s law comprises four papers presented in scientific talks at the Society for Industrial and Applied Mathematics Conference on Analysis of Partial Differential Equations (PD19) on December 12, 2019. The papers are: Almost-sure exponential mixing of passive scalars by the stochastic Navier-Stokes equations and Almost-sure enhanced dissipation and uniform-in-diffusivity exponential mixing for advection-diffusion by stochastic Navier-Stokes, presented by Jacob Bedrossian; Lagrangian chaos and scalar advection in stochastic fluid mechanics, presented by Alex Blumenthal; and The Batchelor spectrum of passive scalar turbulence in stochastic fluid mechanics, presented by Samuel Punshon-Smith.

    See the full article here .


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    About CMNS

    The thirst for new knowledge is a fundamental and defining characteristic of humankind. It is also at the heart of scientific endeavor and discovery. As we seek to understand our world, across a host of complexly interconnected phenomena and over scales of time and distance that were virtually inaccessible to us a generation ago, our discoveries shape that world. At the forefront of many of these discoveries is the College of Computer, Mathematical, and Natural Sciences (CMNS).

    CMNS is home to 12 major research institutes and centers and to 10 academic departments: astronomy, atmospheric and oceanic science, biology, cell biology and molecular genetics, chemistry and biochemistry, computer science, entomology, geology, mathematics, and physics.

    Our Faculty

    Our faculty are at the cutting edge over the full range of these disciplines. Our physicists fill in major gaps in our fundamental understanding of matter, participating in the recent Higgs boson discovery, and demonstrating the first-ever teleportation of information between atoms. Our astronomers probe the origin of the universe with one of the world’s premier radio observatories, and have just discovered water on the moon. Our computer scientists are developing the principles for guaranteed security and privacy in information systems.

    Our Research

    Driven by the pursuit of excellence, the University of Maryland has enjoyed a remarkable rise in accomplishment and reputation over the past two decades. By any measure, Maryland is now one of the nation’s preeminent public research universities and on a path to become one of the world’s best. To fulfill this promise, we must capitalize on our momentum, fully exploit our competitive advantages, and pursue ambitious goals with great discipline and entrepreneurial spirit. This promise is within reach. This strategic plan is our working agenda.

    The plan is comprehensive, bold, and action oriented. It sets forth a vision of the University as an institution unmatched in its capacity to attract talent, address the most important issues of our time, and produce the leaders of tomorrow. The plan will guide the investment of our human and material resources as we strengthen our undergraduate and graduate programs and expand research, outreach and partnerships, become a truly international center, and enhance our surrounding community.

    Our success will benefit Maryland in the near and long term, strengthen the State’s competitive capacity in a challenging and changing environment and enrich the economic, social and cultural life of the region. We will be a catalyst for progress, the State’s most valuable asset, and an indispensable contributor to the nation’s well-being. Achieving the goals of Transforming Maryland requires broad-based and sustained support from our extended community. We ask our stakeholders to join with us to make the University an institution of world-class quality with world-wide reach and unparalleled impact as it serves the people and the state of Maryland.

    Our researchers are also at the cusp of the new biology for the 21st century, with bioscience emerging as a key area in almost all CMNS disciplines. Entomologists are learning how climate change affects the behavior of insects, and earth science faculty are coupling physical and biosphere data to predict that change. Geochemists are discovering how our planet evolved to support life, and biologists and entomologists are discovering how evolutionary processes have operated in living organisms. Our biologists have learned how human generated sound affects aquatic organisms, and cell biologists and computer scientists use advanced genomics to study disease and host-pathogen interactions. Our mathematicians are modeling the spread of AIDS, while our astronomers are searching for habitable exoplanets.

    Our Education

    CMNS is also a national resource for educating and training the next generation of leaders. Many of our major programs are ranked among the top 10 of public research universities in the nation. CMNS offers every student a high-quality, innovative and cross-disciplinary educational experience that is also affordable. Strongly committed to making science and mathematics studies available to all, CMNS actively encourages and supports the recruitment and retention of women and minorities.

    Our Students

    Our students have the unique opportunity to work closely with first-class faculty in state-of-the-art labs both on and off campus, conducting real-world, high-impact research on some of the most exciting problems of modern science. 87% of our undergraduates conduct research and/or hold internships while earning their bachelor’s degree. CMNS degrees command respect around the world, and open doors to a wide variety of rewarding career options. Many students continue on to graduate school; others find challenging positions in high-tech industry or federal laboratories, and some join professions such as medicine, teaching, and law.

  • richardmitnick 4:47 pm on January 9, 2020 Permalink | Reply
    Tags: "Department of Energy picks New York over Virginia for site of new particle collider", , , , , , , Physics,   

    From BNL via Science Magazine: “Department of Energy picks New York over Virginia for site of new particle collider” 

    From Brookhaven National Lab


    Science Magazine

    Jan. 9, 2020
    Adrian Cho

    Nuclear physicists’ next dream machine will be built at Brookhaven National Laboratory in Upton, New York, officials with the Department of Energy (DOE) announced today. The Electron-Ion Collider (EIC) will smash a high-energy beam of electrons into one of protons to probe the mysterious innards of the proton. The machine will cost between $1.6 billion and $2.6 billion and should be up and running by 2030, said Paul Dabbar, DOE’s undersecretary for science, in a telephone press briefing.

    This schematic shows how the EIC will fit within the tunnel of the Relativistic Heavy Ion Collider (RHIC, background photo), reusing essential infrastructure and key components of RHIC.

    Electrons will collide with protons or larger atomic nuclei at the Electron-Ion Collider to produce dynamic 3-D snapshots of the building blocks of all visible matter.

    The EIC will allow nuclear physicists to track the arrangement of the quarks and gluons that make up the protons and neutrons of atomic nuclei.

    “It will be the first brand-new greenfield collider built in the country in decades,” Dabbar said. “The U.S. has been at the front end in nuclear physics since the end of the Second World War and this machine will enable the U.S. to stay at the front end for decades to come.”

    The site decision brings to a close the competition to host the machine. Physicists at DOE’s Thomas Jefferson National Accelerator Facility in Newport News, Virginia, had also hoped to build the EIC.

    Protons and neutrons make up the atomic nucleus, so the sort of work the EIC would do falls under the rubric of nuclear physics. Although they’re more common than dust, protons remain somewhat mysterious. Since the early 1970s, physicists have known that each proton consists of a trio of less massive particles called quarks. These bind to one another by exchanging other quantum particles called gluons.

    However, the detailed structure of the proton is far more complex. Thanks to the uncertainties inherent in quantum mechanics, its interior roils with countless gluons and quark-antiquark pairs that flit in and out of existence too quickly to be directly observed. And many of the proton’s properties—including its mass and spin—emerge from that sea of “virtual” particles. To determine how that happens, the EIC will use its electrons to probe the protons, colliding the two types of particles at unprecedented energies and in unparalleled numbers.

    Researchers at Jefferson lab already do similar work by firing their electron beam at targets rich with protons and neutrons. In 2017, researchers completed a $338 million upgrade to double the energy of the lab’s workhorse, the Continuous Electron Beam Accelerator Facility.

    Continuous Electron Beam Accelerator Facility

    With that electron accelerator in hand, Jefferson lab researchers had hoped to build the EIC by adding a new proton accelerator.

    Brookhaven researchers have studied a very different type of nuclear physics. Their Relativistic Heavy Ion Collider (RHIC) [below] collides nuclei such as gold and copper to produce fleeting puffs of an ultrahot plasma of free-flying quarks and gluons like the one that filled the universe in the split second after the big bang. The RHIC is a 3.8-kilometer-long ring consisting of two concentric and counter-circulating accelerators. Brookhaven researchers plan to make the EIC by using one of the RHIC’s rings to accelerate the protons and to add an electron accelerator to the complex.

    To decide which option to take, DOE officials convened an independent EIC site selection committee, Dabbar says. The committee weighed numerous factors, including the relative costs of the rival plans, he says. Proton accelerators are generally larger and more expensive than electron accelerators.

    The Jefferson lab won’t be left out in the cold, Dabbar says. Researchers there have critical expertise in, among other things, making the superconducting accelerating cavities that will be needed for the new collider. So, scientists there will participate in designing, building, and operating the new collider. “We certainly look forward to [the Jefferson lab] taking the lead in these areas,” Dabbar says.

    The site decision does not commit DOE to building the EIC. The project must still pass several milestones before researchers can being construction—including the approval of a detailed design, cost estimate, and construction schedule. That process can take a few years. However, the announcement does signal the end for the RHIC, which has run since 1999. To make way for the new collider, the RHIC will shut down for good in 2024, Dabbar said at the briefing.

    The decision on a machine still 10 years away reflects the relative good times for DOE science funding, Dabbar says. “We’ve been able to start on every major project that’s been on the books for years.” DOE’s science budget is up 31% since 2016—in spite of the fact that under President Donald Trump, the White House has tried to slash it every year.

    See the full article here .


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    BNL RHIC Campus

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    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world. Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.

  • richardmitnick 10:57 am on January 9, 2020 Permalink | Reply
    Tags: "New open release allows theorists to explore LHC data in a new way", , , , , , Physics, The first open release of full analysis likelihoods from an LHC experiment.   

    From CERN ATLAS: “New open release allows theorists to explore LHC data in a new way” 

    CERN/ATLAS detector

    CERN ATLAS Higgs Event

    CERN ATLAS another view Image Claudia Marcelloni ATLAS CERN


    9 January, 2020
    Katarina Anthony

    The ATLAS collaboration releases full analysis likelihoods, a first for an LHC experiment.

    Explore ATLAS open likelihoods on the HEPData platform. (Image: CERN)

    What if you could test a new theory against LHC data? Better yet, what if the expert knowledge needed to do this was captured in a convenient format? This tall order is now on its way from the ATLAS collaboration, with the first open release of full analysis likelihoods from an LHC experiment.

    “Likelihoods allow you to compute the probability that the data observed in a particular experiment match a specific model or theory,” explains Lukas Heinrich, CERN research fellow working for the ATLAS Experiment. “Effectively, they summarise every aspect of a particular analysis, from the detector settings, event selection, expected signal and background processes, to uncertainties and theoretical models.” Extraordinarily complex and critical to every analysis, likelihoods are one of the most valuable tools produced at the LHC experiments. Their public release will now enable theorists around the world to explore ATLAS data in a whole new way.

    The ATLAS open likelihoods are available on HEPData, an open-access repository for experimental particle physics data. The first open likelihoods released were for a search for supersymmetry in proton–proton collision events containing Higgs bosons, numerous jets of b-quarks and missing transverse momentum. “While ATLAS had published likelihood scans focused on the Higgs boson in 2013, those did not expose the full complexity of the measurements,” says Kyle Cranmer, Professor at New York University. “We hope this first release – which provides the full likelihoods in all their glory – will form a new communication bridge between theorists and experimentalists, enriching the discourse between the communities.”

    The search for new physics will benefit significantly from open likelihoods. “If you’re a theorist developing a new idea, your first question is likely: ‘Is my model already excluded by experiments at the LHC?’” says Giordon Stark, postdoctoral scholar at SCIPP, UC Santa Cruz. “Until now, there was no easy way to answer this.”

    Likelihoods are an essential link between theory and ATLAS data. (Image: K. Cranmer/ATLAS)

    “We plan to make the open release of likelihoods a regular part of our publication process, and have already made them available from a search for the direct production of tau slepton pairs,” says Laura Jeanty, ATLAS Supersymmetry working group convenor. “Over the coming months, we aim to collect feedback from theorists outside the collaboration to best understand how they are using this new resource to further refine future releases.”

    Read more on the ATLAS website.

    See the full article here .

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  • richardmitnick 10:30 am on January 9, 2020 Permalink | Reply
    Tags: "Electrons and positrons in an optimised stellarator", , At KIT Wendelstein a hydrogen plasma is used to investigate how energy can be generated by nuclear fusion reactions., Confine a matter-antimatter plasma in a magnetic cage of a small optimised stellarator., Eve Stenson, , KIT Wendelstein 7-AS built in built in Greifswald Germany, , New idea: APEX-D electron-positron plasma trap., Physics, The APEX collaboration, The research group “Electrons and Positrons in an Optimised Stellarator”,   

    From Max Planck Institute for Plasma Physics: Women in STEM-“Electrons and positrons in an optimised stellarator” Eve Stenson 

    MPIPP bloc

    From Max Planck Institute for Plasma Physics

    January 09, 2020

    Dr. Eve Stenson.Photo: IPP, Axel Griesch

    Helmholtz Young Investigators Group headed by Eve Stenson takes up work.

    Dr. Eve Stenson is one of ten young researchers selected by the Helmholtz Association in 2018 to establish their own research group. This was preceded by a multi-stage competition procedure with external peer review.

    From December 2019, Eve Stenson, born in Cleveland, Ohio/USA in 1981, is working with her IPP junior research group “Electrons and Positrons in an Optimised Stellarator” to create a plasma of electrons and their antiparticles, the positrons. The aim of this new branch of the APEX collaboration is to confine a matter-antimatter plasma in a magnetic cage of a small optimised stellarator. It is much simpler but still related to the large stellarator devices of fusion researchers such as Wendelstein 7-X in Greifswald.

    KIT Wendelstein 7-AS built in built in Greifswald, Germany

    There, a hydrogen plasma is used to investigate how energy can be generated by nuclear fusion reactions.

    Magnetically confined matter-antimatter plasmas have been investigated theoretically and computationally for several decades. However, such a plasma has never been produced in the laboratory before. According to theory, it should show special properties, such as being very stably trapped in certain magnetic field configurations, including optimised stellarators. The aim of the new junior research group will be to produce such plasmas and to investigate them experimentally – thus bringing together two frontiers of plasma physics research, i.e. stellarator optimisation and pair plasma experimentation.

    Design of the APEX-D electron-positron plasma trap. A circular superconducting magnet coil (red) is producing the dipole field inside a vacuum vessel. This coil is levitated by a ring-shaped conductor (pink) which is installed above the vessel. It attracts the coil feedback-controlled. Graphic: IPP

    The exotic matter-antimatter plasmas differ from the “normal” plasmas of fusion researchers in one important respect: while the positively and negatively charged particles in an electron-positron plasma have exactly the same mass, the positively charged hydrogen ions in fusion plasmas are much heavier than the negatively charged electrons. This leads to a very different behaviour. The investigation of exotic matter-antimatter plasmas is therefore expected to provide fundamental insights into the physics of plasmas in general and opportunities to test computational simulations of plasma behaviour. It should even be possible to gain new insights about optimisation that can be used for the planning of new stellarators for fusion research. Since it is assumed that matter-antimatter plasmas occur in the vicinity of neutron stars and black holes, it is also astrophysically interesting to investigate these strange plasmas.

    Including last year’s – fifteenth – selection round, the Helmholtz Association has so far made 230 junior research groups possible. The costs – 300,000 euros per year for each group over a period of six years – are shared between the institute where the IPP is based and the Helmholtz Association, to which the IPP is affiliated as an associated institute.

    See the full article here .

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    MPIPP campus

    The Max Planck Institute of Plasma Physics (Max-Planck-Institut für Plasmaphysik, IPP)is a physics institute for the investigation of plasma physics, with the aim of working towards fusion power. The institute also works on surface physics, also with focus on problems of fusion power.

    The IPP is an institute of the Max Planck Society, part of the European Atomic Energy Community, and an associated member of the Helmholtz Association.

    The IPP has two sites: Garching near Munich (founded 1960) and Greifswald (founded 1994), both in Germany.

    It owns several large devices, namely

    the experimental tokamak ASDEX Upgrade (in operation since 1991)
    the experimental stellarator Wendelstein 7-AS (in operation until 2002)
    the experimental stellarator Wendelstein 7-X (awaiting licensing)
    a tandem accelerator

    It also cooperates with the ITER and JET projects.

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