John William Negele (born 18 April 1944 in Cleveland, Ohio) is an American theoretical nuclear physicist.
Negele studied electrical engineering at Purdue University with a bachelor's degree in 1965. He received his PhD in theoretical physics from Cornell University in 1969 under the supervision of Hans Bethe with dissertation The Structure of Finite Nuclei in the Local Density Approximation. [1] He was a postdoc at the Niels Bohr Institute of the University of Copenhagen. From 1970 he was at MIT, first as a visiting assistant professor, and then from 1979 as a professor [2] (becoming in 1991 "W.A. Coolidge Professor"). He was the director of the Center for Theoretical Physics at MIT from 1989 to 1998 and is the director of the Atomic Science Institute at MIT (Laboratory of Nuclear Science, LNS).
Negele's research deals with many-body theory in nuclear physics (including local density approximation, [3] [4] time-dependent Hartree-Fock (TDHF) methods, and path integral methods) and also with many-body theory in spin systems. He originated the first density functional theory of finite nuclei starting from realistic (experimentally justified) nucleon-nucleon interactions. In doing so, he, with colleagues, calculated binding energies of nuclei, single-particle excitation energies, charge distributions, and nuclear matter properties in neutron stars. Since the 1980s he has dealt with lattice QCD. He was also involved in the design of special computer clusters for such calculations. [5]
He was a Guggenheim Fellow for the academic year 1982–1983 [6] and received the Humboldt Research Award. He was elected a Fellow of the American Physical Society (APS) in 1978 and a Fellow of the American Association for the Advancement of Science in 1987. [7] In 2014, he received the Herman Feshbach Prize in Theoretical Nuclear Physics for "lifetime contributions to nuclear many-body theory including identifying mechanisms for saturation and relating the Skyrme interaction to fundamental nuclear forces; and for initiating and leading efforts to understand the nucleon using lattice QCD." [8]
He served as the first chair of the APS committee Computational Physics. [8]
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.
The Relativistic Heavy Ion Collider is the first and one of only two operating heavy-ion colliders, and the only spin-polarized proton collider ever built. Located at Brookhaven National Laboratory (BNL) in Upton, New York, and used by an international team of researchers, it is the only operating particle collider in the US. By using RHIC to collide ions traveling at relativistic speeds, physicists study the primordial form of matter that existed in the universe shortly after the Big Bang. By colliding spin-polarized protons, the spin structure of the proton is explored.
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.
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.
The QCD vacuum is the vacuum state of quantum chromodynamics (QCD). It is an example of a non-perturbative vacuum state, characterized by non-vanishing condensates such as the gluon condensate and the quark condensate in the complete theory which includes quarks. The presence of these condensates characterizes the confined phase of quark matter.
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.
The MIT Center for Theoretical Physics (CTP) is the hub of theoretical nuclear physics, particle physics, and quantum information research at MIT. It is a subdivision of MIT Laboratory for Nuclear Science and Department of Physics.
Understanding the structure of the atomic nucleus is one of the central challenges in nuclear physics.
Nuclear matter is an idealized system of interacting nucleons that exists in several phases of exotic matter that, as of yet, are not fully established. It is not matter in an atomic nucleus, but a hypothetical substance consisting of a huge number of protons and neutrons held together by only nuclear forces and no Coulomb forces. Volume and the number of particles are infinite, but the ratio is finite. Infinite volume implies no surface effects and translational invariance.
David B. Kaplan is an American physicist. He is a Professor of Physics at the University of Washington where he was Director of the Institute for Nuclear Theory during the period 2006-2016 and is now a Senior Fellow.
In applied mathematics, the numerical sign problem is the problem of numerically evaluating the integral of a highly oscillatory function of a large number of variables. Numerical methods fail because of the near-cancellation of the positive and negative contributions to the integral. Each has to be integrated to very high precision in order for their difference to be obtained with useful accuracy.
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.
Gerald Edward Brown was an American theoretical physicist who worked on nuclear physics and astrophysics. Since 1968 he had been a professor at the Stony Brook University. He was a distinguished professor emeritus of the C. N. Yang Institute for Theoretical Physics at Stony Brook University.
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; however, it is a numerical approach formulated in Euclidean space rather than physical Minkowski space-time.
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.
In nuclear physics, ab initio methods seek to describe the atomic nucleus from the bottom up by solving the non-relativistic Schrödinger equation for all constituent nucleons and the forces between them. This is done either exactly for very light nuclei or by employing certain well-controlled approximations for heavier nuclei. Ab initio methods constitute a more fundamental approach compared to e.g. the nuclear shell model. Recent progress has enabled ab initio treatment of heavier nuclei such as nickel.
Several hundred metals, compounds, alloys and ceramics possess the property of superconductivity at low temperatures. The SU(2) color quark matter adjoins the list of superconducting systems. Although it is a mathematical abstraction, its properties are believed to be closely related to the SU(3) color quark matter, which exists in nature when ordinary matter is compressed at supranuclear densities above ~ 0.5 1039 nucleon/cm3.
The Herman Feshbach Prize in Theoretical Nuclear Physics is a prize awarded annually by the American Physical Society to recognize and encourage outstanding achievements in theoretical nuclear physics. The $10,000 prize is in honor of Herman Feshbach of MIT. The prize, inaugurated in 2014, is awarded to one person or is shared among two to three persons when all of the recipients are credited with the same accomplishment.
Fredrik "Fred" Zachariasen (1931–1999) was an American theoretical physicist, known for his collaborative work with Murray Gell-Mann, Sidney Drell, and others.
Zoltan Fodor is a Hungarian theoretical particle physicist, best known for his works in lattice QCD by numerically solving the theory of the strong interactions.
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