Enhanced contribution of the pairing gap to the QCD equation of state at large isospin chemical potential

Abstract

I study QCD at large isospin density, which is known to be in the superfluid state with Cooper pairs carrying the same quantum number as pions. I solve the gap equation derived from the perturbation theory up to the next-to-leading order corrections. The pairing gap at large isospin chemical potential is found to be enhanced compared to the color-superconducting gap at large baryon chemical potential due to the $\sqrt{2}$ difference in the exponent arising from the stronger attraction in one-gluon exchange in the singlet channel. Then, using the gap function, I evaluate the contribution of the condensation energy of the superfluid state to the QCD equation of state. At isospin chemical potential of a few GeV, where the lattice QCD and the perturbative QCD can be both applied, the effect of the condensation energy becomes dominant even compared to the next-to-leading order corrections to the pressure in the perturbation theory. It resolves the discrepancy between the recent lattice QCD results and the perturbative QCD result.

13 pages, 3 figures; v3: published version

References in corpus (24)

• Color superconductivity in dense quark matter
• FLAG Review 2021
• Cold Quark Matter
• The QCD crossover at finite chemical potential from lattice simulations
• Nuclear Physics from Lattice QCD
• How perturbative QCD constrains the Equation of State at Neutron-Star densities
• Phenomenological QCD equation of state for massive neutron stars
• Trace anomaly as signature of conformality in neutron stars
• Deconfinement in dense 2-color QCD
• Finite-density lattice QCD and sign problem: current status and open problems
• Ab-initio QCD calculations impact the inference of the neutron-star-matter equation of state
• n-Boson Energies at Finite Volume and Three-Boson Interactions
• Towards the phase diagram of dense two-color matter
• Cold quark matter at N3LO: soft contributions
• Equation of state and speed of sound of isospin-asymmetric QCD on the lattice
• Magnetic structure of isospin-asymmetric QCD matter in neutron stars
• Perturbative QCD and the Neutron Star Equation of State
• The Energy of n Identical Bosons in a Finite Volume at O(L^{-7})
• Equation of State of Cold Quark Matter to $O({\alpha }_s^3\ln {\alpha }_s)$
• Dense 2-color QCD towards continuum and chiral limits
• Sign problem and phase quenching in finite-density QCD: models, holography, and lattice
• Color Screening by Pions
• Study of two color QCD on large lattices
• QCD inequalities for hadron interactions

Cited by in corpus (9)

• QCD constraints on isospin-dense matter and the nuclear equation of state
• Pressure and speed of sound in two-flavor color-superconducting quark matter at next-to-leading order
• Novel Scalings of Neutron Star Properties from Analyzing Dimensionless Tolman--Oppenheimer--Volkoff Equations
• On the origin of the peak of the sound velocity for isospin imbalanced strongly interacting matter
• Color superconductivity under neutron-star conditions at next-to-leading order
• Speed of sound peak in isospin QCD: a natural prediction of the Medium Separation Scheme
• Approaching Stable Quark Matter
• QCD Vacuum Energy and Its Implication for Quark Nugget Stability
• Thermal quarks and Polyakov loops in two-color dense QCD