Neutron stars in the large- N c limit

Introductory Visual Lecture on QCD at Large \(N_{c}\): Bound States, Chiral Models, and Phase Diagram

“…We follow here one possible choice described in Ref. [42] that corresponds to a confined stiff matter with the speed of sound equal to the speed of light. Intuitively, it corresponds to an interaction-dominated gas.…”

“…One may apply the previous discussion about baryonic and quark matter to neutron stars, see Ref. [42] for details.…”

“…In the end, we recall -concisely -some relevant facts concerning the large-N c behavior of QCD at finite temperature and density, concentrating on the phase diagram and the quarkyonic phase [35][36][37][38], chiral models in the medium [24,39], nuclear matter [4,40], and neutron stars [41,42].…”

“…In a more realistic treatment, one may consider at high density PB = aBµ α B − K (with α a free parameter) which needs to be matched to the known equation of state of nuclear matter at about 2n0[42]. The large-Nc behavior is not affected.…”

Wheeler--DeWitt Universe Wave Function in the Presence of Stiff Matter

“…Quite remarkably, recent studies on the most dense form of strongly interacting matter, taking place in the core of neutron stars, show that the speed of sound should be larger than 1/3 (the value for a non-interacting ultrarelativistic gas of massless particles) in order to explain the existence of massive neutron stars [18]. The study of this causal limit is common in neutron stars, since it is the stiffest possible Equation of State (EoS) and it is useful to set the limit to the highest possible mass [19][20][21]. Theoretically, it is well understood how such a gas emerges due to strong interactions [22].…”