Observational constraints on spinning, relativistic Bose-Einstein condensate stars

Abstract

Bose-Einstein condensates (BECs) have been proposed as candidate states of matter for the interior of neutron stars. Specifically, Chavanis and Harko obtained the mass-radius relation for a BEC star and proposed that the recently discovered neutron stars with masses around 2M⊙ are BEC stars. They employed a barotropic equation of state (EOS), with one free parameter, that was first found by Colpi, Wasserman, and Shapiro (CSW), to describe them and derive stable equilibrium configurations of spinning BEC stars in General Relativity. In this work we show that while it is true that BECs allow for compact object masses as heavy as the heaviest observed ones, such stars cannot simultaneously have radii that are small enough to be consistent with the latest observations, in spite of the flexibility available in the EOS in the form of the free parameter. In fact, our conclusion applies to any spinning relativistic boson star that obeys the CSW EOS.

Quark Wigner distributions using light-front wave functions

“…Thus, we have now studied Wigner distributions of quark in different polarizations in the dressed quark model using LFWFs. We have used an improved method for the numerical integration that gives better convergence of the results, and the dependence on ∆ max present in our earlier work [41,42] is removed. Wigner distributions contain information that one cannot extract from GPDs and TMDs, as they may contain a correlation between quarks and gluons in transverse position and three-momentum.…”

“…The five-dimensional space consists of two transverse position and three momentum coordinates. Various phenomenological models like the light-cone constituent quark model [39], chiral quark soliton model [40], light-front dressed quark model [41,42], light-cone spectator model [43,44] and diquark model [45,46] have been used to study Wigner distributions. A complete multipole analysis of the quark Wigner distributions including transverse polarization was recently studied [47].…”

Wigner distributions and GTMDs in a proton using light-front quark–diquark model

“…Many theoretical attempts have been made in various models to study the Wigner distributions of nucleons, for example, the light-front dressed quark model [27,28], the light-cone spectator model [29], the light-cone chiral quark soliton model [30][31][32], the light-front quarkdiquark model [33] and the AdS/QCD inspired quark-diquark model [34][35][36]. Using Wigner distributions, the spin-orbital correlations can also be studied [35,37].…”

Three Dimensional Imaging of the Nucleon

“…The Fourier transform is performed numerically using the Levin method [13] for integration which is well-suited for our oscillatory integrals, it gives converging results with respect to the change of the upper limit of the ∆ ⊥ = ∆ max in the numerical integration. This is an improvement compared to our earlier works [14,15]. Figure.…”