Towards the Hadron-Quark Continuity Via a Topology Change in Compact Stars

TL;DR

This paper develops a topological and symmetry-based effective field theory approach to dense matter in compact stars, proposing a hadron-quark continuity without phase transition, and predicts star properties consistent with observations.

Contribution

It introduces a novel EFT framework incorporating hidden symmetries and topology change to describe dense matter and star properties, differing from traditional phase transition models.

Findings

Predicts maximum star mass of about 2.3 solar masses.

Foresees rapid convergence of sound velocity to 1/3 at three times nuclear density.

Provides a topological mechanism for the soft-to-hard EoS crossover.

Abstract

We construct a generalized EFT approach to dense compact-star matter that exploits the CCP for hadron-quark continuity at high density, hidden topology and hidden symmetries of QCD. No Landau-Ginzburg-Wilsonian-type phase transition is involved. The microscopic DoF of QCD possibly intervening at high baryonic density are traded in for fractionalized topological objects. Essential in the description are symmetries invisible in QCD in the matter-free vacuum: Scale symmetry, flavor local symmetry and parity-doubling. The partial emergence of scale symmetry is signaled by a dilatonic scalar in a "pseudo-conformal" structure. Flavor gauge symmetry manifests with the $\rho$ meson mass going toward a Wilsonian RGFP identified with the VMFP at which the gauge boson mass goes to zero. Parity doubling is to take place as the quasi-nucleon mass converges to the chiral invariant $m_0$. The theory accounts satisfactorily for all known properties of normal nuclear matter and makes certain predictions that are drastically different from what's available in the literature. In particular, it provides a topological mechanism, argued to be robust, for the cross-over from soft-to-hard EoS that predicts the star properties in overall agreement with the presently available data, including the maximum star mass $M_{max}\sim 2.3 M_\odot$ and the recent LIGO/Virgo GW data. What is most glaringly different from all other approaches known, however, is the prediction for the rapid convergence to a sound velocity of star $v_s^2\approx 1/3$ at a density $n\gsim 3 n_0$, far from the asymptotic density $\gsim 50n_0$ expected in pQCD. We interpret this to signal the onset of albeit approximate conformal symmetry in dense compact-star matter. The model developed here could bring out a new paradigm in nuclear/hadron physics, exploiting ideas in condensed matter physics, nuclear and particle physics and astrophysics.