Conveners
QCD at Non-zero Temperature
- Alexei Bazavov (Michigan State University)
QCD at Non-zero Temperature
- David A. Clarke (University of Utah)
QCD at Non-zero Temperature
- Tamás G. Kovács (Department of Theoretical Physics, Eotvos Lorand University)
QCD at Non-zero Temperature
- Claudio Bonanno (IFT UAM/CSIC Madrid)
QCD at Non-zero Temperature
- Masakiyo Kitazawa (YITP, Kyoto University)
We discuss the properties of Quantum Chromodynamics at finite temperature obtained by means of lattice simulations with the overlap fermion discretization. This fermion discretization preserves chiral symmetry even at finite lattice spacing. We present the details of the formulation and discuss the properties of the chiral thermal phase transition. We compare the results obtained with the...
Quantum chromodynamics (QCD) which is the theory of strong interactions describes the thermodynamics of strongly interacting matter at finite temperatures and densities. At low temperatures, chiral symmetry is broken in the QCD vacuum and as temperature increases, a transition occurs where chiral symmetry is restored, resulting in the formation of the quark gluon plasma (QGP). It is found that...
We present calculations of the complex potential at non-zero temperature in 2+1 flavor QCD.
The complex potential is obtained from spectral reconstruction of the Wilson line correlators
at non-zero temperature calculated on the lattice. The calculations are performed using the HISQ
action at three lattice spacings, a=0.028 fm, a=0.04 fm and a=0.049 fm for temperatures in the range
130 MeV...
The order of finite temperature QCD phase transition on the lower left corner of Columbia plot is yet to be determined, and the current studies show that the bound of critical mass has a strong cutoff and discretization scheme dependence. We present an update on the QCD phase transition with 3 flavors of Möbius domain wall fermions at zero chemical potential. We performed simulations on...
Based on simulations of 2+1 flavor lattice QCD with M\"obius domain wall fermions at high temperatures, we use a series of recently developed spatial correlation functions to study the screened masses for quarks in meson bound states. We compare these screened masses with the symmetries of the correlators using a pair of fitting ansatz for various quark masses and lattice sizes with...
We study the $U(1)_A$ anomaly at high temperatures of $N_f=2+1$ lattice QCD with chiral fermions. Gauge ensembles are generated with M\"obius domain-wall (MDW) fermions, and in the measurements, the determinant is reweighted to that of overlap fermions. We report the results for the Dirac spectra, the $U(1)_A$ susceptibility, and the topological susceptibility at temperatures, T=136, 153, 175,...
We solve the long-standing problem concerning the fate of the chiral $U(1)_A$
symmetry in QCD-like theories at high temperature in the chiral limit. We
introduce a simple instanton based random matrix model that precisely
reproduces the properties of the lowest part of the lattice overlap Dirac
spectrum. We show that in the chiral limit the instanton gas splits into a
free gas component...
We perform a finite-size scaling analysis of the critical point in the heavy-quark region of QCD at nonzero temperature. Our previous analysis at $N_t=4$ is extended to a finer lattice with $N_t=6$ and $8$. The aspect ratio is also extended up to 18 to suppress the non-singular contribution. High-precision analysis of the Binder cumulant is realized by an efficient Monte-Carlo simulation with...
The deconfinement transition in QCD is understood as the spontaneous breaking of $\mathbb{Z}_N$ symmetry at high temperatures. Accordingly, quark-gluon plasma generally includes some partial cells called center domains, each with a homogeneous Polyakov-loop. In this work, constructing an effective action describing the deconfinement vacuum of QCD with $N$ colors, we discuss the properties of...
We describe how the general mechanism of partial deconfinement applies to large-N QCD and the partially-deconfined phase inevitably appears between completely-confined and completely-deconfined phases. Furthermore, we propose how the partial deconfinement can be observed in the real-world QCD with SU(3) gauge group. We propose how the Polyakov loop and chiral condensate should behave and test...
The effect of a finite volume presents itself both in heavy ion experiments as well as in recent model calculations. The magnitude is sensitive to the proximity of a nearby critical point. We calculate the finite volume effects at finite temperature in continuum QCD using lattice simulations. We focus on the vicinity of the chiral crossover. We investigate the impact of finite volumes at zero...
The 't Hooft anomaly matching condition provides constraints on the phase structure at $\theta=\pi$ in 4D SU($N$) Yang-Mills theory. In particular, assuming that the CP symmetry is spontaneously broken at low temperature, it cannot be restored below the deconfining temperature at $\theta=\pi$. Here we investigate the CP restoration at $\theta=\pi$ in the 4D SU(2) case and provide numerical...
We compute the screening masses of fields with nucleon quantum numbers for a wide range of temperatures between $T \sim 1$ GeV and $T\sim 160$ GeV. The computation has been performed by means of Monte Carlo simulations of lattice QCD with $N_f=2+1$ flavors of $O(a)$-improved Wilson fermions: we exploit a novel strategy which has recently allowed to determine for the first time non-singlet...
We establish that the charmed hadrons start dissociating at the chiral crossover temperature, $\mathrm{T_{pc}}$, leading to the appearance of charm degrees freedom carrying fractional baryon number. Our method is based on analyzing the second and fourth-order cumulants of charm ($\mathrm{C}$) fluctuations, and their correlations with baryon number ($\mathrm{B}$), electric charge ($\mathrm{Q}$)...
We investigate a possible relation between the chiral susceptibility and axial U(1) anomaly in lattice QCD at high temperatures. Employing the exactly chiral symmetric Dirac operator, we can separate the purely axial U(1) breaking effect in the connected and disconnected chiral susceptibilitesin a theoretically clean manner. Preliminary results for 2 and 2+1 flavor lattice QCD near the...
'Fit' independent methods are used to investigate temperature effects for the singly and doubly charmed spin $1/2$ baryons on the anisotropic FASTSUM 'Generation 2L' ensembles. Thereafter we determine where it is appropriate to apply standard fitting procedures in order to report the change in mass as the temperature increases. The negative parity sector is observed to be more strongly...
Macroscopic properties of the strong interaction near its chiral phase transition exhibit scaling behaviors, which are the same as those observed close to the magnetic transition in a 3-dimensional classical spin system with $O(4)$ symmetry. We show the universal scaling properties of the chiral phase transition in Quantum Chromodynamics (QCD) at the macroscale are, in fact, encoded within the...
We investigate the chiral transition of $U(N)$ lattice gauge theory based on the strong coupling expansion. A generalized vertex model with vertices and weights derived from the tensor network approach of the dual representation of lattice QCD with staggered fermions is used and the configurations are sampled by the Metropolis algorithm. We study the chiral transition in the chiral limit and...
We present first non-perturbative results for the renormalization constants of the QCD energy momentum tensor, based on the framework of thermal QCD with shifted and twisted (for quarks only) boundary conditions in the compact direction. We also show preliminary results for the entropy density obtained with the very same numerical strategy. This opens the way to the determination of the QCD...
Non-orthogonal background electromagnetic fields generate a non-zero expectation value for the topological charge in QCD. For sufficiently weak fields, a linear response is expected. This linear response has been studied and related to the QCD contribution to the axion-photon coupling, for which we give preliminary results at finite lattice spacing. We also investigated the dependence of the...
We present the first lattice QCD results of the second order fluctuations of and correlations among net baryon number, electric charge and strangeness in (2+1)-flavor lattice QCD in the presence of a background magnetic field with physical pion mass $m_\pi$ = 135 MeV. To mimic the magnetic field strength produced in the early stage of heavy-ion collision experiments we use 6 different values...
We present the first continuum extrapolated results for the chiral magnetic effect (CME) and the chiral separation effect (CSE) conductivities in equilibrium with staggered fermions at physical masses. We simulate QCD in a constant magnetic background and measure respective chemical potential derivatives of the currents appearing in each effect. The conductivities are calculated as a function...
The complex Langevin method shows great promise in enabling the calculation of observables for theories with complex actions. Nevertheless, real-time quantum field theories have remained largely unsolved due to the particular severity of the sign problem. In this contribution, we will discuss our recent progress in applying the complex Langevin method to SU(2) Yang-Mills theory in 3+1...
We compute the sphaleron rate on the lattice. We adopt a novel strategy based on the extraction of the spectral density via a modified version of the Backus-Gilbert method from finite-lattice-spacing and finite-smoothing-radius Euclidean topological charge density correlators. The physical sphaleron rate is computed by performing controlled continuum limit and zero-smoothing extrapolations.
The thermal photon emissivity at the QCD chiral crossover is
investigated using imaginary momentum correlators. These have been
measured on a newly generated $20 \times 96^3$ lattice-QCD ensemble
with $\mathrm{O}(a)$-improved Wilson quarks and physical up, down and
strange quark masses at a temperature $T=154$ MeV near the
pseudo-critical temperature. In order to realize the photon...
Using numerical lattice simulations, we analyze the influence of uniform rotation on the equation of state of gluodynamics. For a sufficiently slow rotation, the free energy of the system can be expanded into a series of powers of angular velocity. We calculate the moment of inertia given by the quadratic coefficient of this expansion and determine its dependence on the temperature We find...