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Lattice Gauge Theory for the Quark-Gluon Plasma Sourendu Gupta TIFR
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Sep 1, 2007Saturday Show: S. Gupta2 Can particle physics predict the mass of this system? Protein folding and other entropic terms: about 1 eV Binding energy of electrons: 1 keV Electron rest mass: 1 MeV Proton mass: 1 GeV 3-6 digit accuracy!
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Sep 1, 2007Saturday Show: S. Gupta3 The first 3 digits
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Sep 1, 2007Saturday Show: S. Gupta4 Particles in the Standard Model (1990s)
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Sep 1, 2007Saturday Show: S. Gupta5 The Eightfold Way (variables)
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Sep 1, 2007Saturday Show: S. Gupta6 The Eightfold Way (variables)
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Sep 1, 2007Saturday Show: S. Gupta7 The Eightfold Way (variables)
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Sep 1, 2007Saturday Show: S. Gupta8 The Eightfold Way (variables)
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Sep 1, 2007Saturday Show: S. Gupta9
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Sep 1, 2007Saturday Show: S. Gupta10 The basics of extreme matter Normal matter made of baryons Baryons contain 3 quarks and interact by exchanging mesons Mesons contain 2 quarks When you squeeze this matter by applying pressure (or heating it up) you get matter with large numbers of quarks This is the quark gluon plasma
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Sep 1, 2007Saturday Show: S. Gupta11 Quark matter factories Create an universe through a big bang and let it cool Create a supernova and let its core collapse into a really compressed star Bang some (relatively) large chunks of matter together very hard Think hard … you may get a patent
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Sep 1, 2007Saturday Show: S. Gupta12 The RHIC at Brookhaven
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Sep 1, 2007Saturday Show: S. Gupta13 Chronology of heavy-ion collisions Initial 1 fm or so: nuclei collide and many particles are created Next 7 fm or so: secondary collisions and flow? Later: particles free stream to detector
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Sep 1, 2007Saturday Show: S. Gupta14 On quark matter Normal matter needs QED or its effective theories There are many phases of normal matter Normal matter may be neutral or a plasma Normal matter may be a solid, liquid or a gas Quark matter needs QCD or its effective theories There are many phases of quark matter Quark matter may be neutral or a plasma Quark matter is fluid: either gas or liquid
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Sep 1, 2007Saturday Show: S. Gupta15 How to pro(b/v)e a liquid Show that there is some matter …count the number of particles coming out of the collision and compute density Show that this generates pressure …elliptic flow: also used in the BEC Does the pressure drive flow? …detailed analysis of velocities Is there transport: energy, baryon etc?
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Sep 1, 2007Saturday Show: S. Gupta16 How to predict its properties Need to use quantum field theory Equation for fields due to Maxwell Equation for matter due to Dirac ∞ first found by Lorentz (self interaction of point particle) ∞ in the quantum theory: Heisenberg, Bethe Removed by Feynman, Schwinger, Tomonaga Modern formulation by Wilson: unifying field theory and statistical mechanics
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Sep 1, 2007Saturday Show: S. Gupta17 The bubbling vacuum Quantum fluctuations: t h/2 Particles can be produced from vacuum for a short time … and disappear again (if no one is looking) Mobile charges the vacuum screens No one measures the charge of an electron without the screening cloud: it is actually ∞ and cancels Lorentz’s ∞ This affects the mass: gauge symmetry
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Sep 1, 2007Saturday Show: S. Gupta18 Charge renormalization: screening in QED
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Sep 1, 2007Saturday Show: S. Gupta19 Anti-screening in QCD Asymptotic freedom is anti-screening: the opposite of electrodynamics
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Sep 1, 2007Saturday Show: S. Gupta20 Numerical renormalization Solve coupled differential equations: Maxwell + Dirac Do it many times: quantum theory is a sum over possibilities (Feynman) Do it on a lattice (spacing d): no infinities in solid state physics e changes with d
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Sep 1, 2007Saturday Show: S. Gupta21 The phase diagram Several phases Several 1st order transitions More than one critical point More variables not shown: tri-critical points… Rajarshi Ray
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Sep 1, 2007Saturday Show: S. Gupta22 Flow parameters P(T) or P(T, ): relativistic gas Equation of state is either E(P) or E(P,N) Speed of sound Specific heat Compressibility Viscosity Swagato Mukherjee
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Sep 1, 2007Saturday Show: S. Gupta23 Lots more to do… Analogues of Debye screening for pions, strange and charmed particles, causing them to dissolve Photon emission rates: is the plasma a black body? Are there plasmons? Supersonic shock waves: jets of particles travel with speed of light through the plasma Quantum coherence created as particles freeze out of the liquid Anything else that you can think of
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Sep 1, 2007Saturday Show: S. Gupta24 It’s totally rewarding
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