119587655
A field theoretical model for QCD thermodynamics
The PNJL model is used to study the thermodynamics of N f = 2 quark flavours interacting through chiral four-point couplings and propagating in a homogeneous Polyakov loop background. The input is fixed exclusively by selected pure-gauge lattice QCD results and by pion properties in vacuum. We present successful comparisons with lattice QCD thermodynamics expanded to finite chemical potential μq. Quark number susceptibilities at finite quark chemical potential are investigated. The validity of the Taylor expansion is then examined through a comparison between the full and truncated PNJL model calculations.
56465034
The chiral and deconfinement crossover transitions: PNJL model beyond mean field ∗
Abstract The Polyakov loop extended Nambu and Jona-Lasinio model (PNJL model) in a mean field framework shows astonishingly good agreement with lattice QCD calculations which needs to be better understood. The present work reports on further developments concerning both Polyakov loop and mesonic fluctuations beyond mean field approximation. Corrections beyond mean field are of special interest for the thermal expectation values of the Polyakov loop 〈 Φ 〉 and its conjugate 〈 Φ ∗ 〉 , which differ once the quark chemical potential is non-zero. Mesonic fluctuations are also considered with emphasis on the role of pionic modes.
119349228
Stability of strange quark matter in the MIT bag model and in the Color Dielectric Model
We utilize the MIT bag model and two different versions of the Color Dielectric Model in order to study the properties of strange matter, and to discuss the stability of strangelets. We also investigate the effect of the introduction of perturbative gluons. The MIT bag model and the Double Minimum version of the Color Dielectric Model allow the existence of strangelets, while the Single Minimum version excludes this possibility.
16977039
The Role of Color-Magnetic Monopoles in a Gluonic Plasma
Abstract The role of color-magnetic monopoles in a pure gauge plasma at high temperature T > 2 T c is considered. In this temperature regime, monopoles can be considered heavy, rare objects embedded into matter consisting mostly of the usual “electric” quasiparticles, quarks and gluons. The gluon-monopole scattering is found to hardly influence thermodynamic quantities, yet it produces a large transport cross section, significantly exceeding that for pQCD gluon-gluon scattering up to quite high T. This mechanism keeps viscosity small enough for hydrodynamics to work at LHC.
55793321
The QCD equation of state with dynamical quarks
The present paper concludes our investigation on the QCD equation of state with 2 + 1 staggered flavors and one-link stout improvement. We extend our previous study [JHEP01 (2006) 089] by choosing even finer lattices. Lattices with Nt=6, 8 and 10 are used, and the continuum limit is approached by checking the results at Nt= 12. A Symanzik improved gauge and a stout-link improved staggered fermion action is utilized. We use physical quark masses, that is, for the lightest staggered pions and kaons we fix the mπ/fK and mK/fK ratios to their experimental values. The pressure, the interaction measure, the energy and entropy density and the speed of sound are presented as functions of the temperature in the range 100 ... 1000MeV. We give estimates for the pion mass dependence and for the contribution of the charm quark. We compare our data to the equation of state obtained by the “hotQCD” collaboration.
14960863
Polyakov loop, diquarks, and the two-flavor phase diagram
An updated version of the PNJL model is used to study the thermodynamics of N{sub f}=2 quark flavors interacting through chiral four-point couplings and propagating in a homogeneous Polyakov loop background. Previous PNJL calculations are extended by introducing explicit diquark degrees of freedom and an improved effective potential for the Polyakov loop field. The mean field equations are treated under the aspect of accommodating group theoretical constraints and issues arising from the fermion sign problem. The input is fixed exclusively by selected pure-gauge lattice QCD results and by pion properties in vacuum. The resulting (T,{mu}) phase diagram is studied with special emphasis on the critical point, its dependence on the quark mass and on Polyakov loop dynamics. We present successful comparisons with lattice QCD thermodynamics expanded to finite chemical potential {mu}.
118612335
Wrapping corrections, reciprocity and BFKL beyond the sl(2) subsector in N=4 SYM
We consider N=4 SYM and a class of spin N, length-3, twist operators beyond the well studied sl(2) subsector. They can be identified at one-loop with three gluon operators. At strong coupling, they are associated with spinning strings with two spins in AdS5. We exploit the Y-system to compute the leading weak-coupling four loop wrapping correction to their anomalous dimension. The result is written in closed form as a function of the spin N. We combine the wrapping correction with the known four-loop asymptotic Bethe Ansatz contribution and analyze special limits in the spin N. In particular, at large N, we prove that a generalized Gribov-Lipatov reciprocity holds. At negative unphysical spin, we present a simple BFKL-like equation predicting the rightmost leading poles.