Larry D. McLerran | |
---|---|
Born | United States |
Nationality | American |
Occupation(s) | Physicist and academic |
Awards | Herman Feshbach Prize, American Physical Society (2015) Pomeranchuk Prize, Institute for Theoretical and Experimental Physics (2021) |
Academic background | |
Education | B.S., Physics PhD, Physics |
Alma mater | University of Washington |
Academic work | |
Institutions | University of Washington |
Larry D. McLerran is an American physicist and an academic. He is a professor of physics at the University of Washington. [1]
McLerran is most known for his work on particle and nuclear physics,primarily focusing on the Color Glass condensate,the Quark–gluon plasma,and Quarkyonic Matter. [2]
McLerran is the recipient of the 2015 Herman Feshbach Prize in Theoretical Physics [3] and the 2021 Pomeranchuk Prize from the Institute for Theoretical and Experimental Physics. [4] He is a Foreign Member of the Finnish Academy of Arts and Sciences. [5]
McLerran completed his Bachelor of Science in physics from the University of Washington in 1971. Later in 1975,he obtained a PhD in Physics from the same institution. [6]
McLerran was a Postdoctoral Research Associate at the Massachusetts Institute of Technology from 1975 to 1978. Following that,he became a Postdoctoral Research Associate at the Stanford Linear Accelerator Center from 1978 to 1980. In 1980,he rejoined the University of Washington as an assistant professor,a role he held until 1984. He was subsequently promoted to the position of Associate Professor in 1984. He became a Scientist in the Theory Division of Fermi National Accelerator Center from 1984 to 1989 and was also an Adjunct Associate Professor at the University of Illinois from 1984 to 1989. He joined the University of Minnesota where he served as a Professor from 1988 to 2000. In addition to his professorial role,he held concurrent appointments as a member of the Fine Theoretical Physics Institute at the University of Minnesota from 1989 to 2000 and as visiting professor at the Nordic Institute of Theoretical Physics from 1996 to 1998. From 1999 to 2016,he was a Senior Scientist at Brookhaven National Laboratory. Since 2016,he has been serving as a professor of physics at the University of Washington and a Senior Fellow of the Institute for Nuclear Theory. [1]
McLerran served as the Director of the Theoretical Physics Institute from 1989 to 1992 at the University of Minnesota. From 1999 to 2004,he was Theory Group Leader of the Nuclear Theory Group at Brookhaven National Laboratory,and from 2003 to 2016 he was Theory Group Leader of the Riken Brookhaven Canter at Brookhaven National Laboratory. [7] From 2016 to 2022,he held the position of Director at the Institute for Nuclear Theory at the University of Washington. [6]
McLerran has conducted research into the characteristics of ultra-relativistic nuclear collisions and the properties of super dense strongly interacting matter. He has authored numerous publications spanning the areas of particle physics,nuclear physics,and Quantum chromodynamics including articles in peer-reviewed journals. [2]
McLerran's work on the Quark Gluon Plasma and the theory of heavy ion collisions has made contributions to the field of nuclear and particle physics. [3] His early research explored the theoretical concept of deconfinement of quarks in dense matter. He computed the energy density of a quark gas to the first order where the density dependence of interactions is important, [8] and explored the possibility that such matter may occur in neutron stars. [9] Furthermore,he showed the existence of a confinement-deconfinement phase transition in a Yang-Mills theory of gluons using Monte-Carlo numerical methods. [10] [11] His work also established that energy densities may be large enough and time scales long enough to form a Quark Gluon Plasma in heavy ion collisions. [12] Additionally,he investigated the emission of photons and dileptons from a quark-gluon plasma and revealed that the emission rates governing the release of photons and dileptons from a quark-gluon plasma are intricately linked to the thermal anticipated value of a correlation function involving electromagnetic currents. [13]
McLerran's Color Glass Condensate research illustrated the importance of color electric and magnetic fields inside of strongly interacting particles responsible for particle interactions at high energies. One of the major focuses of his research for the Electron Ion Collider being built at Brookhaven National Laboratory is to explore the consequences of such color electric and magnetic fields. [14] He and Raju Venugopalan constructed the McLerran-Veungopalan model of strong color electric fields, [15] [16] and then formulated a mathematical equation that delineated the quantum evolution of the effective theory concerning the Color Glass Condensate (CGC). [17] Focusing on nonlinear gluon evolution in the color glass condensate,his study enhanced comprehension of small-x hadronic physics in the high gluon density regime by deriving a functional Fokker-Planck equation and presented the renormalization group equation (RGE) for the Color Glass Condensate,governing its rapidity evolution. [18] The Color Glass Condensate provided initial conditions for the matter formed in heavy ion collisions,and the early time evolution of such matter towards the formation of a Quark Gluon Plasma was the subject of his work on the Glasma. [19] [20]
McLerran used properties of topological excitations,instantons and sphalerons,in electroweak theory to compute the rate of electroweak baryon number violation. [21] [22] With Kharzeev and Warringa,he developed insight into the effect of topological anomalous effects in strongly interacting theory,the Chiral Magnetic Effect wherein a polarize system and electric field is generated parallel to an externally applied magnetic field. [23]
McLerran and Pisarski proposed the existence of Quarkyonic Matter,a form of high density matter with quark confinement,yet which largely behaves like a gas of unconfined quarks,which may exist at densities intermediate between that of nuclear matter and that of a deconfined Quark Gluon Plasma. [24] Moreover,he and Reddy also argued that Quarkyonic Matter may have the properties needed to explain determinations of neutron star equations of state. [25]
A gluon is a type of elementary particle that mediates the strong interaction between quarks,acting as the exchange particle for the interaction. Gluons are massless vector bosons,thereby having a spin of 1. Through the strong interaction,gluons bind quarks into groups according to quantum chromodynamics (QCD),forming hadrons such as protons and neutrons.
A quark is a type of elementary particle and a fundamental constituent of matter. Quarks combine to form composite particles called hadrons,the most stable of which are protons and neutrons,the components of atomic nuclei. All commonly observable matter is composed of up quarks,down quarks and electrons. Owing to a phenomenon known as color confinement,quarks are never found in isolation;they can be found only within hadrons,which include baryons and mesons,or in quark–gluon plasmas. For this reason,much of what is known about quarks has been drawn from observations of hadrons.
In theoretical physics,quantum chromodynamics (QCD) is the theory 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.
In particle physics,strangeness ("S") is a property of particles,expressed as a quantum number,for describing decay of particles in strong and electromagnetic interactions which occur in a short period of time. The strangeness of a particle is defined as:
In theoretical physics,anti-de Sitter/conformal field theory correspondence is a conjectured relationship between two kinds of physical theories. On one side are anti-de Sitter spaces (AdS) which are used in theories of quantum gravity,formulated in terms of string theory or M-theory. On the other side of the correspondence are conformal field theories (CFT) which are quantum field theories,including theories similar to the Yang–Mills theories that describe elementary particles.
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.
The
J/ψ
(J/psi) meson is a subatomic particle,a flavor-neutral meson consisting of a charm quark and a charm antiquark. Mesons formed by a bound state of a charm quark and a charm anti-quark are generally known as "charmonium" or psions. The
J/ψ
is the most common form of charmonium,due to its spin of 1 and its low rest mass. The
J/ψ
has a rest mass of 3.0969 GeV/c2,just above that of the
η
c,and a mean lifetime of 7.2×10−21 s. This lifetime was about a thousand times longer than expected.
Hadronization is the process of the formation of hadrons out of quarks and gluons. There are two main branches of hadronization:quark-gluon plasma (QGP) transformation and colour string decay into hadrons. The transformation of quark-gluon plasma into hadrons is studied in lattice QCD numerical simulations,which are explored in relativistic heavy-ion experiments. Quark-gluon plasma hadronization occurred shortly after the Big Bang when the quark–gluon plasma cooled down to the Hagedorn temperature when free quarks and gluons cannot exist. In string breaking new hadrons are forming out of quarks,antiquarks and sometimes gluons,spontaneously created from the vacuum.
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 theoretical physics,the anti-de Sitter/quantum chromodynamics correspondence is a goal to describe quantum chromodynamics (QCD) in terms of a dual gravitational theory,following the principles of the AdS/CFT correspondence in a setup where the quantum field theory is not a conformal field theory.
Color-glass condensate (CGC) is a type of matter theorized to exist in atomic nuclei when they collide at near the speed of light. During such collision,one is sensitive to the gluons that have very small momenta,or more precisely a very small Bjorken scaling variable. The small momenta gluons dominate the description of the collision because their density is very large. This is because a high-momentum gluon is likely to split into smaller momentum gluons. When the gluon density becomes large enough,gluon-gluon recombination puts a limit on how large the gluon density can be. When gluon recombination balances gluon splitting,the density of gluons saturate,producing new and universal properties of hadronic matter. This state of saturated gluon matter is called the color-glass condensate.
William Allen Zajc is a U.S. physicist and the I.I. Rabi Professor of Physics at Columbia University in New York,USA,where he has worked since 1987.
The timeline of particle physics lists the sequence of particle physics theories and discoveries in chronological order. The most modern developments follow the scientific development of the discipline of particle physics.
In particle physics hexaquarks,alternatively known as sexaquarks,are a large family of hypothetical particles,each particle consisting of six quarks or antiquarks of any flavours. Six constituent quarks in any of several combinations could yield a colour charge of zero;for example a hexaquark might contain either six quarks,resembling two baryons bound together,or three quarks and three antiquarks. Once formed,dibaryons are predicted to be fairly stable by the standards of particle physics.
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 high-energy nuclear physics,strangeness production in relativistic heavy-ion collisions is a signature and diagnostic tool of quark–gluon plasma (QGP) formation and properties. Unlike up and down quarks,from which everyday matter is made,heavier quark flavors such as strange and charm typically approach chemical equilibrium in a dynamic evolution process. QGP is an interacting localized assembly of quarks and gluons at thermal (kinetic) and not necessarily chemical (abundance) equilibrium. The word plasma signals that color charged particles are able to move in the volume occupied by the plasma. The abundance of strange quarks is formed in pair-production processes in collisions between constituents of the plasma,creating the chemical abundance equilibrium. The dominant mechanism of production involves gluons only present when matter has become a quark–gluon plasma. When quark–gluon plasma disassembles into hadrons in a breakup process,the high availability of strange antiquarks helps to produce antimatter containing multiple strange quarks,which is otherwise rarely made. Similar considerations are at present made for the heavier charm flavor,which is made at the beginning of the collision process in the first interactions and is only abundant in the high-energy environments of CERN's Large Hadron Collider.
The NA49 experiment was a particle physics experiment that investigated the properties of quark–gluon plasma. The experiment's synonym was Ions/TPC-Hadrons. It took place in the North Area of the Super Proton Synchrotron (SPS) at CERN from 1991-2002.
Bedangadas Mohanty is an Indian physicist specialising in experimental high energy physics,and is affiliated to National Institute of Science Education and Research,Bhubaneswar. He has been awarded the Infosys Prize in Physical Sciences for 2021 that was announced on 2 December 2021. He was awarded the Shanti Swarup Bhatnagar Prize for Science and Technology in 2015,the highest science award in India,in the physical sciences category. He has been elected as the fellow of the Indian National Science Academy,New Delhi,Indian Academy of Sciences,Bangalore and National Academy of Sciences,India. In 2020,he was elected as a fellow of American Physical Society.
Chiral magnetic effect (CME) is the generation of electric current along an external magnetic field induced by chirality imbalance. Fermions are said to be chiral if they keep a definite projection of spin quantum number on momentum. The CME is a macroscopic quantum phenomenon present in systems with charged chiral fermions,such as the quark–gluon plasma,or Dirac and Weyl semimetals. The CME is a consequence of chiral anomaly in quantum field theory;unlike conventional superconductivity or superfluidity,it does not require a spontaneous symmetry breaking. The chiral magnetic current is non-dissipative,because it is topologically protected:the imbalance between the densities of left-handed and right-handed chiral fermions is linked to the topology of fields in gauge theory by the Atiyah-Singer index theorem.
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.