464 research outputs found
A theory of finite-temperature Bose-Einstein condensates in neutron stars
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 finite-temperature scenario, generalizing existing approaches, and
derive macroscopic and astrophysically relevant quantities like a mass limit
for neutron stars.Comment: 21 pages, 9 figures; replaced after publication with additional
comment
Black Hole Remnants in the Early Universe
We consider the production of primordial micro black holes (MBH) remnants in
the early universe. These objects induce the universe to be in a
matter-dominated era before the onset of inflation. Effects of such an epoch on
the CMB power spectrum are discussed and computed both analytically and
numerically. By comparison with the latest observational data from the WMAP
collaboration, we find that our model is able to explain the quadrupole anomaly
of the CMB power spectrum.Comment: 31 pages, 24 figures, revtex4. Some references added, some minor
change
The zeroth law in quasi-homogeneous thermodynamics and black holes
Motivated by black holes thermodynamics, we consider the zeroth law of
thermodynamics for systems whose entropy is a quasi-homogeneous function of the
extensive variables. We show that the generalized Gibbs-Duhem identity and the
Maxwell construction for phase coexistence based on the standard zeroth law are
incompatible in this case. We argue that the generalized Gibbs-Duhem identity
suggests a revision of the zeroth law which in turns permits to reconsider
Maxwell's construction in analogy with the standard case. The physical
feasibility of our proposal is considered in the particular case of black
holes.Comment: 8 pages, 7 figure
- …