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Zoltan Fodor | |
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| Born | |
| Nationality | Hungarian, German |
| Alma mater | Eotvos Lorand University, Budapest, Hungary |
| Known for | Numerical Quantum Field Theory, Lattice QCD |
| Scientific career | |
| Fields | Theoretical Particle Physics |
Zoltan Fodor is a Hungarian-German theoretical particle physicist, best known for his works in lattice quantum chromodynamics.
Fodor was born in 1964 in Budapest, Hungary. At high school and at university he won several national competitions in mathematics, physics and chemistry. He did his undergraduate studies at the Eotvos Lorand University in Budapest, where he received his PhD in 1990. He was postdoctoral fellow at DESY in Hamburg, CERN in Geneva [1] and KEK in Tsukuba.
In 1998 he became a professor at the Lorand Eotvos University, Budapest, Hungary. In 2003 he moved to the University of Wuppertal in Germany. [2] In 2020 he moved to Pennsylvania State University in the United States. [3]
Fodor is widely known for his results in lattice QCD. Many of his findings represent the first fully controlled lattice calculations using ab-initio quantum chromodynamics and quantum electrodynamics.
In 2000 he proposed a method. [4] to circumvent the sign problem at finite baryonic chemical potentials or densities. The numerical sign problem is one of the major unsolved problems in the physics of many particle systems. In 2006 he determined the nature of the QCD transition in the early universe. [5] Since the transition turned out to be an analytic one no observable cosmic relics are expected from this transition. In a series of papers he also calculated the absolute scale of the QCD transition. [6] The equation of state of the strongly interacting matter plays a crucial role both in cosmology and in heavy ion collisions, which he determined in 2010. [7] By calculating the topological susceptibility in the early universe at high temperatures, he gave a prediction for the axion's mass in 2016. Axions are one of the mostly advocated candidates for dark matter.
Since 2005 he has been the spokesperson of the Budapest-Marseille-Wuppertal Collaboration focusing on QCD phenomena at vanishing temperature. In 2008 they determined the light hadron spectrum, which explains the mass of the visible universe [8] In 2015 the mass difference between the neutron and the proton (and other so-called isospin splittings) were calculated. [9] This 0.14 percent neutron-proton mass difference is responsible—among others—for the existence of atoms, as we know them, or for the ignition of stars. In 2021 they determined the anomalous magnetic dipole moment of the muon. This quantity is widely believed to indicate new physics beyond the Standard Model. However, the Budapest-Marseille-Wuppertal Collaboration obtained a theory-based result [10] agreeing more with the experimental value than with the previous theory-based value that relied on the electron-positron annihilation experiments.
In theoretical physics, quantum chromodynamics (QCD) is the study of the strong interaction between quarks mediated by gluons. Quarks are fundamental particles that make up composite hadrons such as the proton, neutron and pion. QCD is a type of quantum field theory called a non-abelian gauge theory, with symmetry group SU(3). The QCD analog of electric charge is a property called color. Gluons are the force carriers of the theory, just as photons are for the electromagnetic force in quantum electrodynamics. The theory is an important part of the Standard Model of particle physics. A large body of experimental evidence for QCD has been gathered over the years.
An exotic atom is an otherwise normal atom in which one or more sub-atomic particles have been replaced by other particles of the same charge. For example, electrons may be replaced by other negatively charged particles such as muons or pions. Because these substitute particles are usually unstable, exotic atoms typically have very short lifetimes and no exotic atom observed so far can persist under normal conditions.
In physics, lattice gauge theory is the study of gauge theories on a spacetime that has been discretized into a lattice.
In physics, an effective field theory is a type of approximation, or effective theory, for an underlying physical theory, such as a quantum field theory or a statistical mechanics model. An effective field theory includes the appropriate degrees of freedom to describe physical phenomena occurring at a chosen length scale or energy scale, while ignoring substructure and degrees of freedom at shorter distances. Intuitively, one averages over the behavior of the underlying theory at shorter length scales to derive what is hoped to be a simplified model at longer length scales. Effective field theories typically work best when there is a large separation between length scale of interest and the length scale of the underlying dynamics. Effective field theories have found use in particle physics, statistical mechanics, condensed matter physics, general relativity, and hydrodynamics. They simplify calculations, and allow treatment of dissipation and radiation effects.
Lattice QCD is a well-established non-perturbative approach to solving the quantum chromodynamics (QCD) theory of quarks and gluons. It is a lattice gauge theory formulated on a grid or lattice of points in space and time. When the size of the lattice is taken infinitely large and its sites infinitesimally close to each other, the continuum QCD is recovered.
In particle physics, quarkonium is a flavorless meson whose constituents are a heavy quark and its own antiquark, making it both a neutral particle and its own antiparticle. The name "quarkonium" is analogous to positronium, the bound state of electron and anti-electron. The particles are short-lived due to matter-antimatter annihilation.
Quark matter or QCD matter refers to any of a number of hypothetical phases of matter whose degrees of freedom include quarks and gluons, of which the prominent example is quark-gluon plasma. Several series of conferences in 2019, 2020, and 2021 were devoted to this topic.
In quantum electrodynamics, the anomalous magnetic moment of a particle is a contribution of effects of quantum mechanics, expressed by Feynman diagrams with loops, to the magnetic moment of that particle. The magnetic moment, also called magnetic dipole moment, is a measure of the strength of a magnetic source.
In particle physics, the parton model is a model of hadrons, such as protons and neutrons, proposed by Richard Feynman. It is useful for interpreting the cascades of radiation produced from quantum chromodynamics (QCD) processes and interactions in high-energy particle collisions.
An onium is a bound state of a particle and its antiparticle. These states are usually named by adding the suffix -onium to the name of one of the constituent particles, with one exception for "muonium"; a muon–antimuon bound pair is called "true muonium" to avoid confusion with old nomenclature.
In quantum chromodynamics, the confining and strong coupling nature of the theory means that conventional perturbative techniques often fail to apply. The QCD sum rules are a way of dealing with this. The idea is to work with gauge invariant operators and operator product expansions of them. The vacuum to vacuum correlation function for the product of two such operators can be reexpressed as
Quark–gluon plasma is an interacting localized assembly of quarks and gluons at thermal and chemical (abundance) equilibrium. The word plasma signals that free color charges are allowed. In a 1987 summary, Léon Van Hove pointed out the equivalence of the three terms: quark gluon plasma, quark matter and a new state of matter. Since the temperature is above the Hagedorn temperature—and thus above the scale of light u,d-quark mass—the pressure exhibits the relativistic Stefan-Boltzmann format governed by temperature to the fourth power and many practically massless quark and gluon constituents. It can be said that QGP emerges to be the new phase of strongly interacting matter which manifests its physical properties in terms of nearly free dynamics of practically massless gluons and quarks. Both quarks and gluons must be present in conditions near chemical (yield) equilibrium with their colour charge open for a new state of matter to be referred to as QGP.
In strong interaction physics, light front holography or light front holographic QCD is an approximate version of the theory of quantum chromodynamics (QCD) which results from mapping the gauge theory of QCD to a higher-dimensional anti-de Sitter space (AdS) inspired by the AdS/CFT correspondence proposed for string theory. This procedure makes it possible to find analytic solutions in situations where strong coupling occurs, improving predictions of the masses of hadrons and their internal structure revealed by high-energy accelerator experiments. The most widely used approach to finding approximate solutions to the QCD equations, lattice QCD, has had many successful applications; It is a numerical approach formulated in Euclidean space rather than physical Minkowski space-time.
Abdel Nasser Tawfik graduated from Assiut University in 1989, where he also completed his master's degree (M.Sc.) in theoretical physics before his change to the Philipps University of Marburg, Germany, for the Dr.rer.Nat. (Ph.D.) in high energy physics. In 2012 Tawfik earned his Doctor of Science degree in mathematics and physics at the Uzbekistan National University. Dr. Tawfik is the Founder Director of the Egyptian Center For Theoretical Physics (ECTP), the Founder Director of the World Laboratory for Cosmology And Particle Physics (WLCAPP), and Research Director at the "ICSC – World Laboratory" in Geneva, Switzerland. Currently, Abdel Nasser Tawfik works as Math and Physics teacher at DEO, and jointly affiliated to Frankfurt Institute for Advanced Studies (FIAS) - Goethe Frankfurt University, Germany. He is the Spokesperson of the Federation for Egyptian Particle Scientists (FEPS) and Associate of the Nuclear Physics Institute of Uzbekistan Academy of Sciences. In 1998, he was awarded the DAAD-prize for “Hervorragende Leistungen ausländischer Studierender an den deutschen Hochschulen". At the 23rd General Meeting of TWAS held in Tianjin, China, on 18 September 2012, he was elected as Fellow of TWAS. Tawfik is the author of four books, and has published about 170 research papers in leading journals.
The light-front quantization of quantum field theories provides a useful alternative to ordinary equal-time quantization. In particular, it can lead to a relativistic description of bound systems in terms of quantum-mechanical wave functions. The quantization is based on the choice of light-front coordinates, where plays the role of time and the corresponding spatial coordinate is . Here, is the ordinary time, is a Cartesian coordinate, and is the speed of light. The other two Cartesian coordinates, and , are untouched and often called transverse or perpendicular, denoted by symbols of the type . The choice of the frame of reference where the time and -axis are defined can be left unspecified in an exactly soluble relativistic theory, but in practical calculations some choices may be more suitable than others. The basic formalism is discussed elsewhere.
Stephan Narison is a Malagasy theoretical high-energy physicist specialized in quantum chromodynamics (QCD), the gauge theory of strong interactions. He is the founder of the Series of International Conferences in Quantum Chromodynamics (QCD-Montpellier) and of the Series of International Conferences in High-Energy Physics (HEPMAD-Madagascar).
Muon g − 2 is a particle physics experiment at Fermilab to measure the anomalous magnetic dipole moment of a muon to a precision of 0.14 ppm, which is a sensitive test of the Standard Model. It might also provide evidence of the existence of new particles.
In quantum chromodynamics (QCD), Brown–Rho (BR) scaling is an approximate scaling law for hadrons in an ultra-hot, ultra-dense medium, such as hadrons in the quark epoch during the first microsecond of the Big Bang or within neutron stars.
John William Negele is an American theoretical nuclear physicist.
Claudia Ratti is a nuclear physicist at University of Houston.
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