A theory of finite-temperature Bose-Einstein condensates in neutron stars

Abstract

We investigate the possible occurrence of a Bose-Einstein condensed phase of matter within neutron stars due to the formation of Cooper pairs among the superfluid neutrons. To this end we study the condensation of bosonic particles under the influence of both a short-range contact and a long-range gravitational interaction in the framework of a Hartree-Fock theory. We consider a finitetemperature scenario, generalizing existing approaches, and derive macroscopic and astrophysically relevant quantities like a mass limit for neutron stars.

Constraints onBose–Einsteincondensate stars as neutron stars models from new observational data

“…Observational evidence associated with the theoretical adjustment of the cooling data of Cassiopeia A has come to reinforce this long‐lasting supposition (Page 2012; Page et al 2011; Shternin et al 2011). Considering NS's typical inner conditions, paired neutrons should be in an intermediate situation between the Bardeen–Copper–Schrieffer and the Bose–Einstein condensate (BEC) limits, prevailing in the former description (Gruber & Pelster 2014). However, assuming the pairs in the BEC limit led, some years ago, to Bose–Einstein condensate stars (BECS) models (Chavanis & Harko 2012).…”

Magnetized vector boson gas at any temperature

“…Moreover, in the last few years new observational evidence has came to reinforce the supposition of a NS superfluid interior [21][22][23]. This superfluid is composed by paired protons and neutrons that, given the star´s typical inner conditions, are expected to be in an intermediate situation between the BCS and the BEC limits [24]. Usually, the paired nucleons are described in the BCS limit, although some descriptions in the BEC limit have also been developed giving birth to BEC stars models [24][25][26][27].…”

“…This superfluid is composed by paired protons and neutrons that, given the star´s typical inner conditions, are expected to be in an intermediate situation between the BCS and the BEC limits [24]. Usually, the paired nucleons are described in the BCS limit, although some descriptions in the BEC limit have also been developed giving birth to BEC stars models [24][25][26][27]. Boson stars are less popular than fermion stars models to describe compact objects, nevertheless, self-gravitating boson systems have been studied since last century not only in connection to compact objects, but also as sources of dark mater and black holes [25,[28][29][30].…”

Magnetized Bose–Einstein condensate stars with boundary conditions depending on magnetic field

“…A Bose–Einstein condensate star (BEC) is a star fully composed of interacting bosons formed by the pairing of two neutrons (Chavanis & Harko ; Gruber & Pelster ; Latifah et al ). BECs have been proposed recently as an alternative model for neutron stars (NS) cores (Chavanis & Harko ).…”