Topology change, emergent symmetries and compact star matter

Abstract

Topology effects have being extensively studied and confirmed in strongly correlated condensed matter physics. In the large color number limit of QCD, baryons can be regarded as topological objects-skyrmions-and the baryonic matter can be regarded as a skyrmion matter. We review in this paper the generalized effective field theory for dense compact-star matter constructed with the robust inputs obtained from the skyrmion approach to dense nuclear matter, relying to possible "emergent" scale and local flavor symmetries at high density. All nuclear matter properties from the saturation density n0 up to several times n0 can be fairly well described. A uniquely noveland unorthdox-feature of this theory is the precocious appearance of the pseudo-conformal sound velocity v 2 s /c 2 ≈ 1/3, with the non-vanishing trace of the energy momentum tensor of the system. The topology change encoded in the density scaling of low energy constants is interpreted as the quark-hadron continuity in the sense of Cheshire Cat Principle (CCP) at density ∼ > 2n0 in accessing massive compact stars. We confront the approach with the data from GW170817 and GW190425.

The sound speed and core of massive compact stars: A manifestation of hadron-quark duality

“…Details are given in the review articles written up recently [13][14][15]. Here we will give only brief description of the basic premise of the theory referring for details to the reviews and focus on the new results obtained and their possible impacts on nuclear astrophysics.…”