Two-colour QCD phases and the topology at low temperature and high density

Abstract

We delineate equilibrium phase structure and topological charge distribution of dense two-colour QCD at low temperature by using a lattice simulation with two-flavour Wilson fermions that has a chemical potential $\mu$ and a diquark source $j$ incorporated. We systematically measure the diquark condensate, the Polyakov loop, the quark number density and the chiral condensate with improved accuracy and $j\to 0$ extrapolation over earlier publications; the known qualitative features of the low temperature phase diagram, which is composed of the hadronic, Bose-Einstein condensed (BEC) and BCS phases, are reproduced. In addition, we newly find that around the boundary between the hadronic and BEC phases, nonzero quark number density occurs even in the hadronic phase in contrast to the prediction of the chiral perturbation theory (ChPT), while the diquark condensate approaches zero in a manner that is consistent with the ChPT prediction. At the highest $\mu$, which is of order the inverse of the lattice spacing, all the above observables change drastically, which implies a lattice artifact. Finally, at temperature of order $0.45T_c$, where $T_c$ is the chiral transition temperature at zero chemical potential, the topological susceptibility is calculated from a gradient-flow method and found to be almost constant for all the values of $\mu$ ranging from the hadronic to BCS phase. This is a contrast to the case of $0.89T_c$ in which the topological susceptibility becomes small as the hadronic phase changes into the quark-gluon plasma phase.

21 pages, 13 figures, (v2) comments and references added, (v3) comments and figures are added

References in corpus (12)

• Color superconductivity in dense quark matter
• The QCD transition temperature: results with physical masses in the continuum limit II.
• Nuclear Force from Lattice QCD
• High-precision scale setting in lattice QCD
• BEC-BCS Crossover in the Nambu--Jona-Lasinio Model of QCD
• Deconfinement in dense 2-color QCD
• Towards the phase diagram of dense two-color matter
• Nambu-Jona-Lasinio model description of weakly interacting Bose condensate and BEC-BCS crossover in dense QCD-like theories
• Hadron Spectrum in a Two-Colour Baryon-Rich Medium
• Behaviour of the topological susceptibility in two colour QCD across the finite density transition
• Characteristics of the eigenvalue distribution of the Dirac operator in dense two-color QCD
• Hadron Wavefunctions as a Probe of a Two Color Baryonic Medium

Cited by in corpus (26)

• Phase Transitions in Particle Physics -- Results and Perspectives from Lattice Quantum Chromo-Dynamics
• Peaks of sound velocity in two color dense QCD: quark saturation effects and semishort range correlations
• Lattice study of thermodynamic properties of dense QC${}_2$D
• Electric conductivity in finite-density SU(2) lattice gauge theory with dynamical fermions
• Effects of Dense Quark Matter on Gluon Propagators in Lattice QC${}_2$D
• Effect of color superconductivity on the mass of hybrid neutron stars in an effective model with pQCD asymptotics
• Thermal quarks and gluon propagators in two-color dense QCD
• Probing the hadron mass spectrum in dense two-color QCD with the linear sigma model
• Fate of the topological susceptibility in two-color dense QCD
• Sound velocity peak induced by the chiral partner in dense two-color QCD
• Study of two color QCD on large lattices
• Role of the effective range in the density-induced BEC-BCS crossover
• When cold, dense quarks in 1+1 and 3+1 dimensions are not a Fermi liquid
• Finite-Density Massless Two-Color QCD at Isospin Roberge-Weiss Point and 't Hooft Anomaly
• Delineating chiral separation effect in two-color dense QCD
• Axial anomaly effect to the chiral-partner structure of diquarks at high temperature
• QCD topology and axion properties in an isotropic hot and dense medium
• Equation of state in neutron stars and supernovae
• Density-Induced Hadron-Quark Crossover via the Formation of Cooper Triples
• Chiral effective model of cold and dense two-color QCD: The linear sigma model approach
• Non-relativistic trace anomaly and equation of state in dense fermionic matter
• The $\theta$-angle and axion physics of two-color QCD at fixed baryon charge. Part I
• QCD phase diagram from the gluon propagator at finite temperature and density
• QCD chiral condensate and pseudoscalar-meson properties in the nuclear medium at finite temperature
• Grassmann tensor renormalization group approach to $(1+1)$-dimensional two-color lattice QCD at finite density
• Thermal quarks and Polyakov loops in two-color dense QCD