Cool Quark Matter

Abstract

We generalize the state-of-the-art perturbative equation of state of cold quark matter to nonzero temperatures, needed in the description of neutron star mergers and core collapse processes. The new result is accurate to Oðg 5 Þ in the gauge coupling, and is based on a novel framework for dealing with the infrared sensitive soft field modes of the theory. The zero Matsubara mode sector is treated via a dimensionally reduced effective theory, while the soft nonzero modes are resummed using the hard thermal loop approximation. This combination of known effective descriptions offers unprecedented access to small but nonzero temperatures, both in and out of beta equilibrium.

Breaking the sound barrier in holography

“…The situation is complicated by a lack of first principles field theory tools: perturbative QCD is only applicable at extremely high densities [3,4], while lattice Monte Carlo simulations are altogether prohibited due to the sign problem [5]. Add to this the fact that robust nuclear physics methods-including their modern formulations, such as the Chiral Effective Theory [6]-are only reliable below the nuclear saturation density n s ≈ 0.16/fm 3 [7].…”

Quark Matter Equation of State from Perturbative QCD

“…In this conference proceedings contribution, we have briefly reviewed two recent results in the field of perturbative finite-density QCD [27,38]. The former generalized an existing three-loop EoS of zerotemperature quark matter to nonzero temperatures, while the latter provided a novel computational aid for perturbative calculations carried out at T = 0 and µ 0.…”

“…In a recent article [27], we revisited the problem of determining the EoS of deconfined QCD matter at all temperatures, only this time from a somewhat different standpoint. We added and subtracted to/from the QCD pressure a function that by definition represents the contributions of the IR sensitive field modes that need to be resummed.…”

“…This leads to the result where it should be noted that the HTL resummation is only applied to the non-static modes. The physical nature and properties of each of these terms is discussed in quite some detail in [27]. Here, we merely note that…”

Phenomenological QCD equations of state for neutron star mergers

“…On the other hand, almost all of them are based on the hadronic descriptions, so the extrapolation of those equations of state beyond ∼ 2 − 3n 0 may be questionable. There are few finite temperature quark equations of state, and they are based on a bag model, or perturbative QCD calculations [27], or a 3-window modeling with a quark model [28]. In these treatments the most relevant excitations are gapless quarks whose contributions to equations of state are much larger than those from gluons, because the larger phase space, ∝ 4π p 2 F , is available for quarks near the Fermi sphere.…”