From quarks and gluons to color superconductivity at supranuclear densities

Abstract

We study the emergence of color superconductivity in the theory of the strong interaction at supranuclear densities. To this end, we follow the renormalization group (RG) flow of dense strong-interaction matter with two massless quark flavors from the fundamental quark and gluon degrees of freedom at high energies down to the non-perturbative low-energy regime which is found to be governed by the dynamical formation of diquark states. With the strong coupling at the initial RG scale as the only input parameter, we compute the (chirally symmetric) scalar diquark condensate and analyze its scaling behavior over a wide range of the quark chemical potential. Approximations entering our computations are critically assessed. Since our approach naturally allows us to study the scale dependence of couplings, we also monitor the strength of couplings appearing in low-energy models of dense strong-interaction matter. The observed dependence of these couplings on the quark chemical potential may help to amend model studies in the future. Finally, we estimate the speed of sound of dense QCD matter. Our results indicate that the speed of sound exceeds the value of the noninteracting quark gas at high densities and even increases as the density is decreased, across a wide range, suggesting the existence of a maximum at supranuclear densities.

22 pages, 5 figures; v2: typos fixed, comments and references added, one section added, two figures added, two appendices added

References in corpus (22)

• GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
• Shapiro delay measurement of a two solar mass neutron star
• A Massive Pulsar in a Compact Relativistic Binary
• Exact evolution equation for the effective potential
• Color superconductivity in dense quark matter
• A NICER View of the Massive Pulsar PSR J0740+6620 Informed by Radio Timing and XMM-Newton Spectroscopy
• Cold Quark Matter
• Sound velocity bound and neutron stars
• Chiral symmetry breaking in continuum QCD
• Two lectures on color superconductivity
• Chiral phase boundary of QCD at finite temperature
• Exact flow equation for composite operators
• On the Nature of the Phase Transition in SU(N), Sp(2) and E(7) Yang-Mills theory
• New equations of state constrained by nuclear physics, observations, and QCD calculations of high-density nuclear matter
• The QCD Phase Boundary from Quark-Gluon Dynamics
• Deconfinement transition in SU(2) Yang-Mills theory: A two-loop study
• From asymmetric nuclear matter to neutron stars: a functional renormalization group study
• Remarks on nuclear matter: how an ${\omega }_0$ condensate can spike the speed of sound, and a model of $Z(3)$ baryons
• Vector and Axial-Vector Mesons in Nuclear Matter
• The Radius of PSR J0740+6620 from NICER and XMM-Newton Data
• Renormalization Group Studies of Dense Relativistic Systems
• Functional renormalization group approach to neutron matter

Cited by in corpus (7)

• QCD at finite temperature and density within the fRG approach: An overview
• What neutron stars tell about the hadron-quark phase transition: a Bayesian study
• Speed of sound in dense strong-interaction matter
• Pressure and speed of sound in two-flavor color-superconducting quark matter at next-to-leading order
• Regulator scheme dependence of the chiral phase transition at high densities
• Color superconductivity under neutron-star conditions at next-to-leading order
• Renormalizing the Quark-Meson-Diquark Model