Nuclear condensate and helium white dwarfs

Abstract

We consider a high density region of the helium phase diagram, where the nuclei form a Bose-Einstein condensate rather than a classical plasma or a crystal. Helium in this phase may be present in helium-core white dwarfs. We show that in this regime there is a new gapless quasiparticle not previously noticed, arising when the constraints imposed by gauge symmetry are taken into account. The contribution of this quasiparticle to the specific heat of a white dwarf core turns out to be comparable in a range of temperatures to the contribution from the particle-hole excitations of the degenerate electrons. The specific heat in the condensed phase is two orders of magnitude smaller than in the uncondensed plasma phase, which is the ground state at higher temperatures, and four orders of magnitude smaller than the specific heat that an ion lattice would provide, if formed. Since the specific heat of the core is an important input for setting the rate of cooling of a white dwarf star, it may turn out that such a change in the thermal properties of the cores of helium white dwarfs has observable implications.

11 pages, 3 figures

References in corpus (9)

• Spontaneous Symmetry Breaking and Nambu-Goldstone Bosons in Quantum Many-Body Systems
• Observability of a projected new state of matter: a metallic superfluid
• Effective Field Theory for Quantum Liquid in Dwarf Stars
• Field Theory for a Deuteron Quantum Liquid
• On the occurrence and detectability of Bose-Einstein condensation in helium white dwarfs
• The phases of deuterium at extreme densities
• Vortex Structure in Charged Condensate
• Phase Transitions of Charged Scalars at Finite Temperature and Chemical Potential
• Two Component Charged Condensate in White Dwarfs

Cited by in corpus (3)

• Thermodynamics of nuclear condensates and phase transitions in white dwarfs
• Searching for Fermi Surfaces in Super-QED
• Field Theory for Zero Sound and Ion Acoustic Wave in Astrophysical Matter