Physics Faculty Members & Research Fields
Faculty Members:
Prof. Halina Abramowicz (Full Professor) participates in two international collaborations, the ATLAS experiment at the Large Hadron Collider (LHC) at CERN, which explores proton-proton interactions at unprecedentedly high centre of mass energy, and the FCAL Collaboration, which develops instrumentation for the forward region of future electron-positron colliders. Both, the present and future colliders, have the objective to explore the properties of the newly discovered Higgs boson. Her main interests and activities focus on precision measurements of the Standard Model predictions, in the strong interaction sector, as the ultimate tools to probe the physics beyond.
Research Achievements include: measurements of the total proton-proton cross section at the energies available at the LHC and characterisation of the proton structure through measurements of double-parton scattering in various final states, extracted in an original way by applying machines learning techniques. On the detector R&D front, the group came up with a unique design of very thin silicon sensor detectors which reduce the radial size of electromagnetic showers by almost a factor two compared to previous developments.
Future directions include: further studies of parton correlation and coherent effects in the proton at the LHC and participation in the design and construction of the LUXE experiment at the European XFEL facility at DESY (Hamburg) to explore non-perturbative quantum electrodynamics in the Schwinger limit of sparking vacuum. In the latter case, the group will apply its expertise in designing compact electromagnetic calorimeters acquired as part of the R&D effort for future electron-positron colliders.
Dr Adi Ashkenazi is an experimental particle physicist, studying the properties of the most elusive yet stable elementary particles known to us, namely the neutrinos. Out of all particles, the three types of neutrinos hold a great mystery. Unlike others, many of their properties are still unknown and the known ones, i.e the existence of their masses, are very hard to explain using the known tools.
All existing experiments are detecting neutrinos via observation of neutrino-nucleus interactions. The nuclear physics aspects of these interaction are not yet well understood and their impact is of non-negligible size.
Ashkenazi’s research plan is focused on estimating the impact of nuclear effects in neutrino experiments, coordinating an effort to leverage electron scattering data to benchmark models and improve neutrino event generators. Ashkenazi is an active member of MicroBooNE and DUNE, a spokesperson of a dedicated electron scattering experiment at JLAB, and a Monte Carlo developer. Her lab plans to produce a series of novel measurements that will improve current models used for neutrino interaction simulations to support the needs of the future DUNE experiment for oscillation precision measurements and New Physics searches.
Dr. Liron Barak (Senior Lecturer) works on discovering new physics, that will manifest itself either as a new resonance particle (lighter or heavier than the newly discovered Higgs Boson) at the Large Hadron Coliider at CERN or as low mass dark matter at the SENSEI (Sub Electron Noise Skipper-CCD Experimental Instrument) experiment at Fermilab (USA).
Research achievements include: usage of the data that was collected by the ATLAS detector during 2015-2016 in order to search for beyond the standard model Higgs particles either decaying to known particles (as tautau, VV, hh etc) or produced from known particles (as h, Z etc) in various mass ranges.
Future directions include: using LHC data collected in 2015-2018 to search for a new low mass particle using novel techniques such as machine learning to identify the boosted regime. In parallel to analysis of the data collected by the prototype of the SENSEI experiment at Fermilab, working on the construction of a larger scale detector which will take data in an underground mine at Canada (Snolab) reaching an unprecedented sensitivity to low-mass dark matter. She will also participate in the design and construction of MATHUSLA, a very large scale experiment above the LHC ring, looking for long-lived-particles escaping detection of the main detectors.
Detector development for High Energy Physic.
Prof. Erez Etzion (Full Professor) is an experimental particle physicist who works on fundamental studies of the Standard Model (SM) of particle physics and searches for extensions or deviations from the theory. In recent years most of the studies are within the international ATLAS Collaboration at the CERN Large Hadron Collider. The research spans a variety of subjects such as studies of the strong interactions of heavy quarks, searches for heavy resonances decaying into leptons, jets or top quarks, studies of jets physics, searches for the so-called exotics extensions to the SM, studies of the properties of the Higgs Boson, discovered by the ATLAS Collaboration in 2012, and searches for Dark Matter with ATLAS as well as with the SENSEI (Sub Electron Noise Skipper-CCD Experimental Instrument) experiment at Fermilab. In addition, develops novel detectors technologies aiming at utilising particle physics techniques in other fields, e.g. medical treatment, homeland security, and archeology.
Research achievements include: exploration of the fundamentals of particle physic with colliding proton beams at unprecedented centre of mass energies from 7 up to 13 TeV. The ATLAS highlight is the discovery of the Higgs particle in 2012 which led to the 2013 Nobel prize in Physics to the theorists who predicted its existence, (one of the two, Francois Englert, is a Sackler Professor at the TAU School of Physics). A key part of the ATLAS detector is the muon endcap trigger system which was built in Israel and tested by Etzion both at the lab at TAU and at CERN. In addition he led the ATLAS programs of searching for Physics Beyond the SM, and Higgs related extensions to the theory, setting severe constraints on the existence of large number of physics models, superseding many pervious experimental bounds.
Future directions include: using the much larger data samples expected from the LHC to improve our understanding of the SM in general, and specifically of the Higgs Boson properties. Design and construct MATHUSLA, a very large scale experiment above the LHC ring looking for long-lived-particles, predicted by many extensions of the SM, escaping detection of the main detectors. Search for Dark Matter candidates with the SENSEI experiment. Its larger scale next generation version will take data at SNOLAB, a Canadian underground mine, reaching an unprecedented sensitivity to low mass dark matter candidates.
Michael Geller (Senior Lecturer) works on particle theory and cosmology, focusing on physics beyond the Standard Model (SM). Topics include dark matter and dark energy, early universe dynamics, collider phenomenology, Higgs physics, and model building. Geller's research is focused on tackling major theoretical problems in our understanding of the universe and finding new exciting experimental and observational predictions that can help us exclude or discover new phenomena.
Research achievements include: significant work on the neutral naturalness paradigm of addressing the Higgs hierarchy problem, with emphasis on the twin Higgs model. In addition, Geller and collaborators have proposed the possibility of learning about the early universe dynamics using the angular information in a possible gravitational wave background. Geller has also proposed a new idea of solving the hierarchy problem of the Higgs with new dynamics at cosmic inflation.
Future directions include: searching for cosmological solutions to the cosmological constant and the Higgs hierarchy problem, studying new ideas in the detection and production of dark matter bound states, looking for new phenomena that can give rise to striking signals in the future observations of cosmic microwave background, large scale structure, and gravitational waves.
Prof. Nissan Itzhaki (Full Professor) works on string theory, field theory, gravity and cosmology. Quantum Field Theory joins together quantum mechanics with the theory of special relativity, and it is the main framework used to study problems in particle physics, and many problems in condensed matter physics. Traditionally this framework starts from a given theory at short distance scales, and uses this to study the physics at larger distances, which can be experimentally measured. Recently it was realized that in some cases one can go in the opposite direction, starting from a long distance theory and deriving in it some short distance physics, that can be different than the standard one of quantum field theories. This leads to many conceptual as well as technical questions that were addressed in the last few years. These questions are likely to affect our understanding of topics ranging from black hole physics to condensed matter physics. At least in the near future he intends to keep on exploring this fascinating direction.
Prof. Marek Karliner (Full Professor) works on a range of topics in Quantum Chromodynamics, focusing on hadrons with heavy quarks. Specific topics include exotic hadrons, i.e. tetraquarks and pentaquarks, baryons with b quarks, as well as baryons containing two heavy quarks.
Research achievements include: accurate prediction of masses of baryons containing a single b quark, prediction of Z_b exotic states on the basis of anomalies in Belle experiment data, prediction of a charmed-anticharmed hadronic molecule subsequently discovered by LHCb at CERN, a highly accurate prediction of the mass of the lightest doubly-charmed baryon Xi_cc subsequently discovered by LHCb, a robust prediction for the first genuine tetraquark stable under strong interactions, (b b ubar dbar), quark-level analogue of nuclear fusion with doubly-heavy baryons, a proposal for using a future Higgs factory in radiative return mode as a high-luminosity QCD collider with CM energy above 12 GeV, discovery of spontaneous breaking of rotational symmetry in rotating solitons and emergence of hexagonal symmetry in 2+1 dimensional Skyrmion crystals.
Future directions include: utilizing the upcoming data from high luminosity pp, e+ e- and heavy ion colliders to search for and deepen the theoretical understanding of stable tetraquarks, doubly-heavy hadrons and new hadronic molecules.
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High-energy electron scattering at various accelerator facilities
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Experimental study of free nucleon structure: Utilizing deeply virtual exclusive processes (DVEP) to study 3D structure of a proton and explore it dynamic properties such as the origin of the spin and the mass
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Studies of bound nucleons: Exploring nucleon-nucleon interactions and the interplay between partonic and nucleonic degrees of freedom within nuclei
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Design of experiments and detectors for the forthcoming EIC collider
Prof. Yaron Oz (Full Professor) works on diverse aspects of Quantum Field Theories, Gravity and Strings. These include the holographic relation between quantum field theories, quantum gravity, black hole hydrodynamics, conformal field theories and turbulence. In recent years Professor Oz proposed an analytical solution to the long-standing problem of turbulence. Most fluid motions in our universe are turbulent. However, despite centuries of research we still lack an analytical description and understanding of fluid flows in the non-linear regime. Turbulence is considered as the most important unsolved problem of classical physics. The turbulent incompressible fluid flows exhibit highly complex spatial and temporal intermittent structures. When considering their statistical average properties, a universal structure is revealed in the inertial range of scales that exhibits homogeneity, isotropy and anomalous scalings. Based on his work in the field of black hole hydrodynamics, he proposed a field theory description of steady state incompressible fluid turbulence at the inertial range of scales, and constructed an analytical formula to calculate them. Prof. Oz is working with experimentalists and computational fluid dynamics researchers in order to verify his proposal. His theory can be generalized to other important systems including superfluids and magneto-hydrodynamics, which he is currently considering with his graduate students. While constructing his turbulence field theory, he also discovered a new class of higher-dimensional generalizations of the famous two-dimensional Liouville conformal field theory and he is currently studying them together with his graduate students.
Prof. Eliazer Piasetzky (Full Professor) main research focuses on the experimental study of nuclear and nucleon structure using high-energy hadron and electron probes. In the last decade and a half, he has concentrated on studies of Short Range Correlation (SRC) in nuclei. He started the SRC project at BNL (USA), and continues now at Jefferson Lab.(USA), GSI (Germany), and Dubna (Russia). In collaboration with Prof. emeritus Lichtenstadt, he is leading an effort to study the difference between free and bound nucleons using polarization transfer measurements at the Mainz MAMI accelerator. He also participates in a neutrino scattering experiment at Fermi Laboratory (MicroBoone) and isone of the pioneers of the proton radius puzzle study at PSI in Switzerland.
Research achievements include: the extraction of the short range pairing probabilities in asymmetric nuclei and pointing to its implication to the understanding of neutron stars and the difference between the internal (quark gluon) structure of a bound and a free nucleon.
Future directions: approved experiments in major accelerator facilities in Europe and U.S.A which will address different fundamental aspects of nucleon structure and nucleon-nucleon interaction, especially at short distances.
Ishay Pomerantz (Senior Lecturer) works on experimental studies of high-intensity laser-matter interaction. His new laboratory hosts a 20 Terawatt laser system. The focused laser pulses instantly ionize matter and induce a large variety of high-energy particle emission.
Research projects include: investigation of highly non-linear emission of extreme UV light from irradiated plasma mirrors and from gas targets, and acceleration of electrons and ions to multi-MeV energies. These reaction products are employed for conducting high-resolution microscopy and for generating a high flux of neutrons, which is used for reaction cross section measurements and for radiography. Research achievements include: Setup of the new laboratory, installation and commissioning of a 20 Terawatt laser system.
Future directions include: Leading experimental activities at the European Extreme Light Infrastructure consortium, which comes online in 2019.
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Quantum simulations of lattice gauge theories with ultra-cold atoms
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Aspects of quantum information in relativistic field theories
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Gravity. Analog black-hole models. BH information loss paradox
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Quantum foundations
Dr. Amit Sever (Senior Lecturer) works on a computational approach to QCD and a deep understanding of quantum gravity via its holographic description in terms of quantum field theory (QFT). Specifically, his research is focused on solving the "Hydrogen atom of QFT" -- an interacting gauge theory in four dimensions that is holographically dual to a theory of gravity. Solving a QFT means to be able to efficiently compute any observable in the theory such as its spectrum, correlation functions, scattering amplitudes, Wilson loops, and color Flux.
Research achievements include: exact computation of planar scattering amplitudes. A solution to the "Plateau Problem in Hyperbolic Spaces" that is holographically dual of scattering amplitudes and certain Wilson loops at strong coupling. Exact solution of the planar quark anti-quark potential. Perturbative computation of correlation functions using integrability. A non-planar duality between scattering amplitudes and Wilson loops.
Future directions include: non-perturbative computation of correlation function and form factors, non-planar corrections to all observables. Non-perturbative bootstrap of the S-matrix of any gapped, Lorentz invariant QFT.
Prof. Abner Soffer (Full Professor) conducts experimental research in several areas of particle physics. He uses data collected by the ATLAS particle detector at the CERN laboratory in Switzerland to search for long-lived particles, such as heavy neutrinos or supersymmetric particles predicted by “new-physics” models. He also uses data collected by the recently constructed Belle-II detector in Japan to precisely measure properties of particles called bottom mesons, which are sensitive to effects of new physics. Until recently he also he used data from the older BABAR detector in California. For the past few years, Soffer has collaborated with Prof. Volansky at TAU and others on development of crystal-based detection of low-mass dark-matter detectors. Soffer also conducts phenomenology research, proposing new measurement methods that take advantage of existing or proposed capabilities of particle accelerators and detectors.
Research achievements include: First search for a decaying, long-lived particle at the LHC collider; tightest constraints on the mass of the proposed gluino particle; first model-independent search for a long-lived particle at a “B-factory” electron-positron collider; first search for a long-lived heavy neutrino; new method to measure matter-antimatter asymmetries in semileptonic B-meson decays; new methods for using precise vertexing at an electron-positron collider; selected to serve as Physics Coordinator of the BABAR Collaboration (360 physicists from 13 countries) in 2011-2012; selected to serve as Co-Leader of the Heavy Flavor Averaging Group (42 physicists from 14 countries) since 2018.
Prof. Jacob Sonnenschein (Full Professor) research has been focused on the HISH (Holography Inspired Stringy Hadron) model. This is a modern version of the stringy description of hadrons: mesons, baryons, glueballs and exotic hadrons that he invented and developed. The research included setting up and developing the basic concepts and tools of the model, in particular the quantization of a bosonic string with particles on its ends. At the same time he has also applied the model to experimental data and found nice agreement with the spectra of all hadrons and their decay width. Using the powerful tool of the gauge/gravity duality, he has also investigated aspects of nuclear matter, in particular its crystalline structure and the phase transition to quark matter. Another topic he investigates is topological non-trivial classical solutions of pure Maxwell theory. He has developed a technique based on special conformal transformations to generate an infinite set of knot-like solutions of the electric and magnetic fields, and showed that similar configurations exist also in pressure-less hydrodynamics. He developed a Lagrangian formulation for the EM configurations which is the first step toward quantizing them.
Prof. Benjamin Svetitsky (Full Professor) leads a group that applies the methods of lattice gauge theory to models that have been proposed to explain the Standard Model and the Higgs particle without postulating fundamental scalar fields. These are gauge theories defined at energy scales well beyond that of the Standard Model. They typically predict new particles that can be seen at or just beyond the limits of the Large Hadron Collider. As gauge theories, they are amenable to numerical simulation with the lattice techniques previously applied to quantum chromodynamics. Their low-energy properties are described by effective field theories, much like the chiral theory that describes low-energy QCD.
Research achievements include: (1) The first calculation of the beta function and the mass anomalous dimension in a variety of gauge theories proposed as walking technicolor models. This led to the elimination of these theories through their inability to generate physical quark masses. (2) The first numerical study of a model of a composite Higgs boson and a partially composite top quark. An extensive survey of its spectrum gave a number of predictions for new particles, but the small size of a matrix element of the baryon current calls into question the partial-compositeness mechanism. (3) The construction of effective field theories that describe chiral dynamics and a light dilaton that can appear in technicolor models. This is essential for interpreting lattice results in the surviving models of this type.
Prof. Lev Vaidman (Full Professor) works on fundamental problems in the foundations of quantum mechanics, quantum information, and quantum optics. He develops interpretations of quantum theory, searches for novel quantum effects, takes part in quantum optics experiments demonstrating peculiar features of quantum mechanics, and designs quantum devices for practical applications.
Research achievements include: Solving the problem of introducing probability in the framework of the many-worlds interpretation and identifying constraints leading to the Born Rule. Introducing, analyzing, and developing counterfactual quantum communication protocols in which no particles are present in the transmission channel. Introducing, analyzing, and implementing in laboratories novel measurement schemes in quantum mechanics: measurements of nonlocal variables, interaction-free measurements, protective measurements, and weak measurements. Devising and demonstrating a novel quantum optics method for alignment. Introducing a way to describe the past of quantum systems based on the two-state vector formalism and explaining paradoxical quantum phenomena. Providing local description of the Aharonov-Bohm effect and thus opening the way for constructing local quantum theory.
Future directions include: Applying ideas of the two-state vector formalism for constructing devices to move forward the ongoing quantum technology revolution, in particular, by analyzing and continuously monitoring quantum systems. Developing the many-worlds interpretation to make it a consensus among physicists and philosophers. Developing practical key distribution device and searching for new quantum effects leading to supremacy of quantum technology.
Prof. Tomer Volansky (Associate Professor) is working on particle physics phenomenology going beyond the Standard Model (SM). Topics include dark matter physics, collider phenomenology, Higgs physics, astroparticle physics, cosmoparticle physics, model building and supersymmetry. The goal of Volansky’s research is to understand better the microscopic quantum description of nature, its elementary particles, interactions and, as a consequence, the inferred evolution of our universe from the Big Bang till today.
Research achievements include: significant work on dark matter physics beyond the so called WIMP scenario, with emphasis on light dark matter. Until Volansky’s work in 2011, it was thought that such light dark matter cannot be directly detected. His work suggested new techniques to do so, with followups of new limits on such dark matter. Since then significant progress has been made and today Volansky is a co-spokeperson of a fully funded dedicated experiment (SENSEI) to search for light dark matter along the lines originally suggested. In addition, Volansky studied other experimental avenues to search for dark matter, many novel scenarios for the production of dark matter in the early universe, and astrophysical and cosmological constraints on various dark matter models. Volansky has also worked on LHC physics, including techniques to constrain new physics that exhibits odd tracks, Higgs collider phenomenology, its effective theory and its possible exotic decays (including lepton-jets for which he became a short-term member of the ATLAS collaboration), and new exotic particle production at colliders. Finally, Volansky studied extensively supersymmetry at low energies, model building applications, and its collider phenomenology.
Future directions include: cosmological solutions to the cosmological constant problem, dark matter searches with the SENSEI experiment, study of non-standard fuzzy dark matter and its astrophysical implications, effective dark matter theories for N-body simulations, model building beyond the Standard Model, and study of possible interpretations and implications of upcoming experimental results ranging from colliders to precision table-top experiments to astrophysical and cosmological observations.
Professors Emeriti:
Yakir Aharonov has been studying the foundations of quantum mechanics for many years now. His research interests are very broad including: Time, nonlocality, topological effects, geometric phase, gauge symmetry, quantum measurements, interpretations of quantum mechanics and more. His main contributions are believed to be the discovery of Aharonov-Bohm effect (together with David Bohm) and weak measurements (together with Lev Vaidman and David Albert). He is also the father of Aharonov-Casher effect, Aharonov-Anandan phase, protective measurement, the Two-State-Vector formalism of quantum mechanics, as well as many other quantum effects. His discoveries have led to fruitful theoretical and experimental research worldwide.
I am studying the properties of proton-proton interactionsat very high energies up to 13 TeV using the ATLAS detector situated at the Large Hadron Collider at CERN. In particular I am interested in the properties of the Bose-Einsteinand Fermi-Dirac correlation as a function of energy and particle masses. The experimental work is supplement by me by my own phenomenological description on these phenomena. In additionI I am working on plans for
future electron-positron colliders, like CLIC and the ILC, in particular in relation to the production and measurement of the polarized incoming beams.
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Theoretical nuclear physics
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Nuclear structure
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Nuclear reactions
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Many –body problems
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Nuclear physics at intermediate energies
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Collective states
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Fundamental symmetries
This is an experimental research in high energy physics using the ATLAS detector in the Large Hadron Collider at CERN. The research is focused around the following topics:
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Precision tests of the Standard Model of elementary particles using events with gauge bosons, such as W, Z and photon.
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Search for new particles and new phenomena predicted by new models which are beyond the Standard Model
Prof. Leonid Frankfurt (Professor Emeritus) works on a range of topics: on the role of color in the short-range internucleon forces, using QCD factorization theorems for the hard diffractive processes which allow predicting new QCD phenomena such as color transparency, color fluctuations phenomena discovered at LHC(ATLAS), BNL(NY), FNAL(Chicago), and TJNF(Virginia); developing the theory of ultraperipheral processes which is used now at any of the large detectors at LHC; on the theory of nuclear shadowing and antishadowing in the hard processes; on the scientific program for the detector PANDA (GSI, Germany). His prediction of universal properties of the yield of short-range internucleon correlations in a nucleus (SRC) in the high energy processes allowed to discover pair and triple nucleon correlations at FNAL, TJNF, BNL, and SLAC (Palo Alto). Works on establishing the QCD dynamics of the core of neutron stars and developing the perturbative pomeron.
Prof. David Horn (Professor Emeritus) Over the past few years his research has focused on developing a methodology in Machine Learning called the "Weight-Shape Decomposition" of a probability function such as the Parzen Window distribution. This provided a new basis for Quantum Clustering (which he developed in 2001), and opened the possibility for novel methods of image analysis. He has applied the latter to MRI brain images of mammals.
Future directions include: to investigate how the Shape component can be incorporated as a predefined filter in layers of Deep Convolutional Networks; continued biomedical research in collaboration with Erez Persi, who is currently in NIH, with the potential of interesting biomedical applications.
Prof. Lawrence Horwitz (Professor Emeritus) has continued studies of a consistent classical and quantum theory in the framework of special relativity. It has resulted in a new proof of a theorem used to find the ground state energy of a many-body system and a new stability analysis in statistical mechanics. He has studied a recent experiment showing interference in time and explained the results in terms of this theory. The theory for a proposed experiment which should demonstrate entanglement of correlated spins (such as spin up-spin down combinations to form spin zero) separated in time was also worked out by Horwitz using the formulation of spin in this theory, resulting in a prediction that could be verified in experiment. He has recently embedded the theory into general relativity as a complete classical and quantum theory, and applications have been worked out, such as dynamical effects in the neighborhood of a black hole horizon, scattering and gauge theory forming a basis for the recent development of an approach to modified Newtonian law behavior of galaxies with anomalous rotation curves. Another topic in his interest has been that of unstable systems. A known theory developed for the description of resonances in classical wave systems was generalized to be applicable to quantum systems. In this form, he developed a theory in which resonances can be represented by actual states in the quantum Hilbert space, providing, for example, a basis for the applicability of particle sum rules. Finally, a new approach to standard Hamiltonian dynamics, embedding it into geometrical form was formulated, making available a criterion for stability based on the local deviation of orbits.
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Study of properties and processes in materials using nuclear radiation phenomena
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Development of cancer treatment based on diffusing alpha emitters radiotherapy
Prof. Aharon Levy (Professor Emeritus) participates in three international collaborations, FCAL, CLICdp and ILD, all three connected with detector R&D for future linear electron-positron colliders. In particular, his group develops a prototype electromagnetic calorimeter for measuring the luminosity, a physical entity necessary for any collider to turn measured events into cross sections.
Research achievements: succeeded to build ultra-thin (~700 microns) silicon sensor planes which allows to build a compact calorimeter. The width of the electromagnetic shower (Moliere radius) was reduced by more than a factor of two from the existing older version.
Future directions: double the size of the existing calorimeter prototype by the end of 2019. In the more-distant future, join the study and development of the LUXE experiment at the European XFEL in Hamburg whose aim is to reach the Schwinger limit predicted in non-perturbative QED in the presence of a high electromagnetic field.
Prof. Murray Moinester (Professor Emeritus) works in the fields of hadron structure and spectroscopy, archaeology, environmental radioactivity, and climate engineering. Participates in Fermilab SELEX and CERN COMPASS collaboration studies of pion polarizability, gluon polarization in nucleons, flavor decomposition of the nucleon spin, search for exotic states, light meson spectroscopy, nuclear dependence of charm production, and kaon Bose–Einstein correlations. His archaeology studies involve multispectral imaging of ostraca and ceramics rehydroxylation studies for scientific dating. Environmental studies deal with the health impact of radioactivity in phosphate fertilizers and its phosphogypsum byproduct, and radon diffusion measurements. Climate studies involve the sequestration of atmospheric carbon dioxide.
Research achievements include: leading the effort to achieve a pion polarizability measurement at CERN COMPASS to provide an important test of chiral perturbation theory, constructing a low cost multispectral imaging laboratory at TAU for imaging ostraca, and using it to observe a biblical-period inscription unnoticed for half a century, climate engineering based on soil composition measurements at Yatir forest in Israel demonstrating how to mitigate global warming by sequestering atmospheric carbon dioxide as inorganic carbon in the unsaturated zone under semi-arid forests.
Future directions: focus on continuing measurements of carbon sequestration and improving measurement methods.
Hadronic high energy scattering, weak interactions astro-particle physics and in particular neutrinos and dark matter issues, suggested and applied QCD inequalities and most recently the physics associated with the newly discovered Higgs particle at the Large Hadronic Collider (LHC).
Prof. Shimon Yankielowicz (Professor Emeritus) works on various non-perturbative and topological aspects of quantum field theories (QFT) such as RG flows and phase structure, anomalies, conformal symmetry and supersymmetry, dualities, entanglement entropy (EE) as well as aspects of gravity, black holes and string theory. In recent years his work concentrates on the implications of the so called AdS/CFT holographic duality which relates strongly coupled QFTs to weakly coupled string theory (gravity) in one higher dimension which is asymptotically AdS space with the dual QFT residing on its boundary. Of particular interest are confining QFTs which resemble QCD, the theory of the strong interactions. He investigated various aspects of QFTs in particular: Renormalization Group (RG) flows and the Weyl a-anomaly theorem; Entanglement Entropy, Reyni Entropy and RG flows; Weyl and Chiral anomalies; Conformal anomalies and hydrodynamics; scattering amplitudes in deformed N=4 Super Yang Mills theory at large coupling; A stringy model for pion-pion scattering in large N QCD; String theory mechanism for supersymmetry breaking; Phase structure of QCD with theta-angle and spontaneous CP violation in QCD and the implication on the Axion potential and the Axion as dark matter; Disorder in large N field theories; Dynamics and phase structure (confinement/de-confinement and spontaneous symmetry breaking) in 4d non-abelian gauge theories on AdS 4d space.
Research achievement include: the study of the regions of parameter space of QCD where CP is spontaneously broken/unbroken for a vacuum angle theta=pi. Using the low energy effective Lagrangian of QCD valid for small quark masses and large N (number of colors) he elucidated the structure of the (hyper)space separating the two regions and the nature of the transition having a second order point (vanishing of the mass of the Nambu-Goldstone boson and divergent topological susceptibility) which sits at the end of a line of first order transitions (associated with the CP breaking). He explored the implications of such phase structure once an axion field which solves the strong CP problem is introduced. The axion potential calculation is revised and the possible importance for axionic dark matter is pointed out. 2. The study of Conformal Field Theories perturbed by quenched disorder, namely by random fluctuations in their couplings. Such theories often flow to new fixed points of the RG flow. Such flows were explored at large N, the exact beta function for the disorder was computed as well as correlation functions of the disordered theory. Both QFT methods as well as holography were used for exploiting the disorder theories. 3. The study of holographic models describing RG flows between two fixed points driven by a relevant scalar operator. The anomalous contribution to the generating functional was computed and found to be proportional to the difference of conformal anomalies of the UV and IR fixed points as expected from anomaly matching arguments. This coefficient is always positive as implied by the holographic a-anomaly theorem. For flows corresponding to spontaneous breaking of conformal invariance he computed some correlation functions and identified the dilaton. 4. The study of the effect of conformal anomalies on the hydrodynamics description of conformal field theories in even space-time dimensions. The local low energy effective action which captures the conformal anomalies was constructed and a formula for the anomaly effect on the hydrodynamic pressure due to the Euler central charge was calculated.
