Towards a semi-classical description of QCD vacuum around $T_c$

Abstract

We study the vacuum topology of 2+1 flavor QCD above the chiral crossover transition, at $T\lesssim 1.2T_c$, on lattices of size $32^3\times 8$. Since overlap fermions have exact chiral symmetry and an index theorem even on a finite lattice, we use them to detect the topological content of gauge fields generated using domain wall fermion discretization for quarks. We further use different periodicity phases along the temporal direction for the valence overlap quarks, which allows us to probe different topological structures present in the gauge field ensembles, through its zero modes. This procedure provides strong evidences that fermion zero-modes can be quantitatively understood to arise due to different species of instanton-dyons. We estimate their relative abundances from the Dirac-eigenvalue density and resolve the so called "topological clusters" via multi-parameter fits to their density, providing therefore an understanding of the interactions between instanton-dyons. The typical separation between dyons we obtain, is $\sim 0.3$ fm. Surprisingly, it emerges out from this study that a semi-classical description of the fermionic zero modes in the QCD vacuum is quite accurate just above $T_c$.

arXiv comment14 pages, 11 Figures

References in corpus (42)

• The order of the quantum chromodynamics transition predicted by the standard model of particle physics
• Instantons in QCD
• A Method for Simulating Chiral Fermions on the Lattice
• The chiral and deconfinement aspects of the QCD transition
• Flavor Symmetry and the Static Potential with Hypercubic Blocking
• Chiral crossover in QCD at zero and non-zero chemical potentials
• Solving Lattice QCD systems of equations using mixed precision solvers on GPUs
• The index theorem in QCD with a finite cut-off
• The QCD phase transition with physical-mass, chiral quarks
• Periodic Instantons with non-trivial Holonomy
• SU(2) Calorons and Magnetic Monopoles
• Monopole Constituents inside SU(n) Calorons
• The topological susceptibility in finite temperature QCD and axion cosmology
• A practical implementation of the Overlap-Dirac operator
• An Accelerated Conjugate Gradient Algorithm to Compute Low-Lying Eigenvalues --- a Study for the Dirac Operator in SU(2) Lattice QCD
• Quantum weights of dyons and of instantons with non-trivial holonomy
• Polyakov loop in 2+1 flavor QCD from low to high temperatures
• Microscopic Origin of \boldmath{$U_A(1)$} Symmetry Violation in the High Temperature Phase of QCD
• Instantons and Magnetic Monopoles on $R^3\times S^1$ with Arbitrary Simple Gauge Groups
• Color screening in (2+1)-flavor QCD
• Chiral observables and topology in hot QCD with two families of quarks
• Topological susceptibility at high temperature on the lattice
• Topology in full QCD at high temperature: a multicanonical approach
• Chiral Condensate in the Deconfined Phase of Quenched Gauge Theories
• Confining Dyon-Anti-Dyon Coulomb Liquid Model I
• Weyl-Dirac zero-mode for calorons
• Light Quarks in the Screened Dyon-Anti-Dyon Coulomb Liquid Model II
• Calorons on the lattice - a new perspective
• Calorons, instantons and constituent monopoles in SU(3) lattice gauge theory
• Interacting Ensemble of the Instanton-dyons and Deconfinement Phase Transition in the SU(2) Gauge Theory
• Instanton-dyon Ensemble with two Dynamical Quarks: the Chiral Symmetry Breaking
• Do classical configurations produce Confinement?
• Instanton-like Contributions to the Dynamics of Yang-Mills Fields on the Twisted Torus
• Constructing SU(N) fractional instantons
• Topology across the finite temperature transition studied by overimproved cooling in gluodynamics and QCD
• Dyons near the transition temperature in lattice QCD
• Exact fermion zero-mode for the new calorons
• The topological objects near the chiral crossover transition in QCD
• The Instanton-Dyon Liquid Model V: Twisted Light Quarks
• The Instanton-Dyon Liquid Model III: Finite Chemical Potential
• Instanton-dyon Ensembles III: Exotic Quark Flavors
• Dyons and Roberge - Weiss transition in lattice QCD

Cited by in corpus (7)

• 50 Years of Quantum Chromodynamics
• Eigenvalues of the QCD Dirac matrix with improved staggered quarks in the continuum limit
• Confinement in non-Abelian lattice gauge theory via persistent homology
• Deconfinement Phase Transition in the $SU(3)$ Instanton-dyon Ensemble
• Correlating confinement to topological fluctuations near the crossover transition in QCD
• Imprints of $U_A(1)$ chiral anomaly and disorder in the Dirac eigenspectrum of QCD at finite temperature
• Chiral Symmetry Breaking and Confinement from an Interacting Ensemble of Instanton-dyons in Two-flavor Massless QCD