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Quark-Gluon Plasma and Lattice QCD. T. Hatsuda (Univ. Tokyo). Probing the Early Universe. Simulating the Early Universe. QCDPAX. STAR@RHIC. What have we learned from lattice QCD simulations?. Contents. Brief introduction to QCD – what one can/cannot do in lattice QCD
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Quark-Gluon Plasma and Lattice QCD T. Hatsuda (Univ. Tokyo) Probing the Early Universe Simulating the Early Universe QCDPAX STAR@RHIC What have we learned from lattice QCD simulations?
Contents • Brief introduction to QCD • – what one can/cannot do in lattice QCD • QCD phase structure • – equation of state • – liberation of color • Plasma properties at T > Tc • – strong coupling plasma ? • – plasma screening and effective potential • – dynamic structure factor • 4. Cold plasma and color superconductivity • – its mechanism • – BCS-BEC crossover • 5. Summary and outlook
Where to find? ●Early Universe ( t < 10 -4 sec): High T, low D ● Deep interior of Neutron star:Low T, High D ●Relativistic Heavy Ion Collisions:High T and/or High D How to describe? Quantum Chromo Dynamics (QCD) Matter under high temperature/pressure Critical Density:1012 kg/cm3 Critical Temperature:1012 K
Color Confinement Effective coupling (αs = g2/4π) αs Asymptotic freedom Energy scale (GeV) Nambu (’66) Gross, Wilczek, Politzer (’73) Wilson (’74) Quantum Chromo Dynamics Chromo- paramagnetism (m > 1)
Heavy quarks Light quarks mc~1.5 GeV mb~5 GeV mt~178 GeV mu~3MeV md~7MeV ms~100MeV Quark flavors
Full QCD Quenched QCD Integration : Monte Carlo with importance sampling Basic idea hypercube slab
Continuum and thermodynamic limits 0.1 fm 2-3 fm Why lattice ? • Well defined QM (finite a and L) • Gauge invariant • Fully non-perturbative What one can do in principle • Equation of state of hot plasma • Phase transition (critical temperature, order etc) • Static and dynamic correlations near equilibrium What one cannot do (at present) • Cold degenerate plasma • Phenomena far from equilibrium
Linear confining string Heavy-quark bound states R 2S+1LJ 0.5 fm 1.0 fm Bali, Phys. Rep. 343 (’01) 1 CP-PACS, Phys. Rev. D65 (’02) 094508 Examples (quenched)
4He 4He H2O λ-line Phase Structure http://boojum.hut.fi/research/theory/typicalpt.html
μB Color Superconductor Quark-Gluon Plasma Triple point ? Hadronic Fluid Critical End point Vacuum T QCD Phase Diagram (full)
Black-body radiation for massless particles : BB limit Nf = 3 Nf = 2+1 Nf = 2 Karsch, Lect.Notes Phys. 583 (’02) 209 Tc~160 MeV ( full)c.f. Tc = 270 MeV (quenched ) Equation of State on the lattice (full)
T=0 Karsch, Laermann, Peikert, Nucl. Phys.B605 (’01) 579 Fate of the color string (full)
Low T Low T low D :Hadronic phase high D :color supercond. ? Quark gluon plasma High T More on QCD Phase Transition at finite T (full) (i) String fluctuation and breaking (ii) Restoration of broken symmetries Pisarski & Wilczek, PRD29 (’84) e.g. Matsuura, Iida, Baym and T.H., PRD69 (’04)
Chiral phase structure from RG Yaffe-Svetizky, (’83) ∞ Pisarski and Wilczek, Phys.Rev.D (’84) m s Nf = 2(ms= ∞, mu,d = 0) 2nd order (O(4) universality) Nf = 3(ms = 0, mu,d = 0) 1st order (fluctuation/instanton induced) 1st 2nd cross over Nf = 2+1(ms >> mu,d ≠0) 1st order or crossover 1st 0 ∞ m u,d Tc from “BCS” lattice QCD 1. Order : consistent with RG 2. Tc= 173±8 MeV (Nf=2) = 154±8 MeV (Nf=3) Kunihiro and T.H., Prog. Theor. Phys. (’85) CP-PACS, Bielefeld
μB QCD Phase Diagram Color superconductor Quark-gluon plasma ~ 1 GeV Hadronic fluid Vacuum ~ 160 MeV T
Static plasma properties at T > Tc
Relativistic plasma : Inter-particle distance Electric screening Magnetic screening Debye number : 1/g2T 1/gT 1/T “Coulomb” coupling parameter : S. Ichimaru, Rev. Mod. Phys. 54 (’82) 1071 QGP for g << 1 ( T >> 100 GeV )
Strong coupling problem g ~ 2 for T=200-400 MeV badly behaved perturbation series B. Non-Abelian magnetic problem soft magnetic gluons are always non-perturbative even if g 0 pertubation theory Problems of high T perturbation
j i Static gluon correlation magnetic screening : A. Linde, Phys. Lett. B96 (’80) 289 EOS : “Debye” screening : Kraemmer & Rebhan, Rept.Prog.Phys.67 (’04)351 QCD is non-perturbative even at T = ∞ ( L3x(1/T) L3 )
Quenched SU(3) 20×20×32×6 Lorenz gauge m = gT Nakamura, Saito & Sakai, Phys.Rev.D69 (’04) 014506 Screening masses at T>Tc (quenched)
T/Tc=3.04 243×6 Lorenz gauge Heavy quark “potentials” at T>Tc (quenched) 0.25fm 0.5fm Nakamura & Saito, Prog.Theor.Phys.111, 112 (’04) hep-lat/0406038, 0404002
γ γ * * Dynamic structure factor of the plasma vacuum plasma Dynamic structure factor of the vacuum PDG(’04) Dynamic plasma properties at T > Tc
probe system lattice QCD data known kernel spectral function = dynamic structure factor Maximum Entropy Method Asakawa, Nakahara & T.H, Phys. Rev. D60 (’99) 091503 Prog. Part. Nucl. Phys. 46 (’01) 459 Method in lattice QCD
Image reconstruction by MEM D = K×A D A D A
Quark-anti-quark ound state above Tc ? charm strange
ccbound state above Tc (quenched) J/ψ(3.1GeV) Spectral function ρ(ω) • J/ψ survives • up to 1.6 Tc • 2. J/ψdisappears • in 1.6 Tc < T < 1.7 Tc Asakawa & T.H., PRL 92 (’04) 012001 see also, Umeda et al, hep-lat/0401010 Datta et al., PRD 69 (’04) 094507
ssbound state above Tc (quenched) Mφ(T=0)=1.03 GeV T/Tc= 1.4 A(ω)/ω2 Asakawa & T.H., Prog. Theor. Phys. Suppl. 149 (‘03)42
Possible mechanisms of supporting “hadrons” above Tc • Strong correlations • in JP=0+ (σ) and JP=0-(π) channels • above Tc • Kunihiro and T.H., Phys. Rev. Lett. 55 (’85) 88 • Dynamical confinement • in all color singlet channels above Tc • DeTar, Phys. Rev. D32 (’85) 276 • Strong Coulomb interaction • in color singlet and non-singlet bound states • above Tc • Shuryak and Zahed, Phys. Rev. D70 (2004) 054507 • Brown, Lee, Rho and Shuryak, Nucl. Phys.A740 (’04) 171
Chiral dynamics pQCD Lattice QCD RHIC, LHC Possible hierarchy of QCD plasma Strongly int. Resonance plasma Strongly int. q+g+”extra” plasma Strongly int. q+g plasma weakly int. q+g plasma Weakly int. pion plasma perfect fluid ? viscous fluid ?
Nakamura and Sakai, hep-lat/0406009 Viscous fluid R << 1 Baym, Monien, Pethick & Ravenhall (’90) Arnold, Moore & Yaffe, (’03) 1.0 1.5 2.0 2.5 3.0 Perfect fluid R >> 1 T/Tc Kovtun, Son & Starinets (’04) “Reynolds number” Shear viscosity (quenched)
? ? Dense Plasma and Color Superconductivity 10 km N. Itoh (’70), E. Witten (’84)
QCD Phase Diagram μB Color superconductor Quark-gluon plasma ~ 1 GeV Hadronic fluid Vacuum T ~ 160 MeV
Major differences from BCS 1. Highlyrelativisitic Long range magnetic int. High Tc superconductor Tc/pF ~ 0.1 Compact Cooper pair size ~ 1-10 fm 2. Color-flavor entanglement Variety of phases CFL, 2SC, dSC, uSC Color Superconductivity in Quark Matter
Abuki, Itakura & T.H., PRD65 (’02) dq 40K Cond. of Fermionic-Atom Pairs ξc N0/N = 1% 5% 10% BCS ξc/dq 40K : JILA, PRL 92 (2004) 040403 6Li : Innsbruck, PRL 92 (2004) 120401 MIT, PRL 92 (2004) 120403 to BEC ? pF(MeV) μB Various scenarios possible: seeFukushima, hep-ph/0403091
Summary and outlook • Progress in lattice QCD • – equation of state of hot plasma • – static and dynamic correlations -> strongly coupled plasma ? • Need to be done • – full QCD for small m, small a and large L • – full QCD for dynamic correlations • (viscosity, colored bound states etc) • Computer resources • – massive computers (>10Tflops) + sharing lattice data • (see, Lattice QCD simulations via International Research Network, • Sep. 21-24, 2004,http://www.rccp.tsukuba.ac.jp/workshop/ilft04/) • 4. Need new ideas • – cold degenerate plasma • – far from equilibrium • – ideas to and from QED plasma and atomic condensates
μB QCD Phase Diagram Color superconductor Quark-gluon plasma ~ 1 GeV new regime? Hadronic fluid Vacuum ~ 160 MeV T
(1989-) (2001-) Planck (2007-) sQGP? RHIC (2000-) LHC (2007-) SPS (1987-) Big Bang Little Bang
Bali, Phys. Rep. 343 (’01) 1 0.5 fm 1.0 fm 323 x 56 – 643 x 112 a=0.1-0.05 fm La=3 fm CP-PACS, PRD 67 (’03) 034503
Quark number susceptibility Kunihiro, Phys. Lett. B271 (’92) 395 Hatta-Ikeda, Phys.Rev.D67 (’03) 014028 Ejiri et al. (Bielefeld-Swansea Coll.)
3He H2O PhaseDiagrams 4He http://boojum.hut.fi/research/theory/typicalpt.html
under heat under pressure