Finite Temperature Quantum Chromodynamics Research Articles

Dynamics of hot QCD matter — Current status and developments

The discovery of hot and dense quantum chromodynamics (QCD) matter, known as Quark–Gluon Plasma (QGP), is an essential milestone in understanding the finite temperature QCD medium. Experimentalists around the world collect an unprecedented amount of data in heavy ion collisions, at Relativistic Heavy Ion Collider (RHIC), at Brookhaven National Laboratory (BNL) in New York, USA, and at the Large Hadron Collider (LHC), at CERN in Geneva, Switzerland. The experimentalists analyze these data to unravel the mystery of this new phase of matter that filled a few microseconds old universe just after the Big Bang. Recent advancements in theory, experimental techniques, and high computing facilities help us to better interpret experimental observations in heavy ion collisions. The exchange of ideas between experimentalists and theorists is crucial for the characterization of QGP. The motivation of this first conference, named Hot QCD Matter 2022 is to bring the community together to have a discourse on this topic. In this paper, there are 36 sections discussing various topics in the field of relativistic heavy ion collisions and related phenomena that cover a snapshot of the current experimental observations and theoretical progress. This paper begins with the theoretical overview of relativistic spin-hydrodynamics in the presence of the external magnetic field, followed by the Lattice QCD results on heavy quarks in QGP. Finally, it concludes with an overview of experimental results.

A survey of lattice results on finite temperature quantum chromodynamics

The talk summarizes some new results of lattice investigations of QCD at finite temperature. The topics discussed cover the flavor dependence of the critical temperature and the equation-of-state as well as hadronic correlation functions.

An Introduction to Finite Temperature Quantum Chromodynamics on the Lattice

In this lecture, we introduce finite temperature QCD on the lattice to non-experts of the subject. We first formulate lattice QCD both at zero and finite temperatures. Then a section is devoted to the topic of improved lattice actions which are becoming an essential ingredient of precision studies of QCD on the lattice. We then discuss about finite temperature SU(3) gauge theory, i.e. QCD without dynamical quarks (quenched QCD). Finally, we report recent status of studies in full QCD taking into account the effects of dynamical quarks. Because of the asymptotic freedom in the UV region, quantum chromodynamics (QCD) is strongly coupled in the IR region. Therefore, it is difficult to study the vacuum structure of QCD by perturbation theory. Two characteristic properties of the QCD vacuum are quark confinement and the spontaneous breakdown of the chiral symmetry. On the other hand, IR properties are affected by temperature. Actually, studies on the lattice have shown that, when the temperature becomes sufficiently high, the low temperature hadronic phase of QCD turns into the high temperature quark-gluon-plasma phase, in which quarks are liberated and chiral symmetry is restored. The quark-gluon-plasma phase is expected to be realized in the early Universe and also possibly in heavy-ion collision experiments. A non-perturbative study is required to understand the QCD vacuum at finite temperatures.

INTERFACES AND THE QUARK HADRON PHASE TRANSITION

The tension of the interface between the high and low temperature phases of finite temperature Quantum Chromodynamics is an important characteristic of the quarkhadron phase transition. We discuss its cosmological effects and its determination, for planar and spherical interfaces, with lattice Monte Carlo techniques for the case of pure glue, Nt=2 SU(3) gauge theory.

Spectral density analysis of the chiral transition in nf=4 finite temperature QCD

We apply the spectral density reweighting technique to the analysis of the chiral phase transition in finite-temperature lattice quantum chromodynamics (QCD) with four flavors of dynamical staggered fermions and m q a=0.025. Our simulations were performed using the hybrid Monte Carlo method for L t L 3 lattices with L t =4 and L=6, 8 and 10. We calculate partition function zeros, as well as the maxima of the specific heat and of the susceptibilities for the Polyakov loop and for the chiral condensate. A finite size scaling analysis of these data leads to preliminary results for the critical coupling β c, for the critical exponent ν, for the latent heat, and for the jumps in the Polyakov loop and in the chiral condensate.

Dimensional reduction in finite-temperature quantum chromodynamics. II.

The reduction of four-dimensional quantum chromodynamics at finite temperature and chemical potential to an infrared-effective three-dimensional theory is further investigated. The effective couplings are calculated in the manner prescribed by a previously discussed program of quantum dimensional reduction, demonstrating its internal consistency and completing the specification of the effective action. The latter provides a starting point for nonperturbative studies of the infrared behavior of high-temperature quark-gluon plasmas.

Dimensional reduction in finite-temperature quantum chromodynamics

The infrared behavior of four-dimensional quantum chromodynamics at finite temperature and chemical potential is examined within the context of perturbation theory. The reduction to an effective three-dimensional theory of the Yang-Mills field coupled to a massive adjoint scalar field is explicitly shown to occur at the one-loop level. A renormalization scheme especially appropriate for the reduction is exhibited. By working in a general Lorentz-covariant gauge, the (well-known) one-loop electrostatic mass is shown to be gauge invariant. Infrared divergences at the two-loop level indicate the need for a nonperturbative treatment of the effective theory; their gauge dependence implies that the naive method for computing the electrostatic mass in covariant gauges is invalid beyond one-loop. Further analysis is carried out in a class of gauges ("static gauges") that are particularly well suited for finite-temperature calculations. The systematic construction of the effective theory is outlined, and performed in a static gauge. At distance scales beyond the electrostatic screening length, pertinent to an investigation of possible magnetostatic screening, the effective theory simplifies further to pure three-dimensional Yang-Mills theory with coupling ${T}^{\frac{1}{2}}g(T)$. This implies that the leading-order magnetostatic mass gap must be proportional to ${g}^{2}T$.