HIGH ENERGY THEORY / RELATIVITY / COSMOLOGY SEMINARS
Friday 9nd March Seminar at 2.30pm :
Title : Nuclear condensates and helium white dwarf stars
The existence of an exotic class of white dwarf stars, the helium-core white dwarfs (He WDs), has been predicted decades ago, but the first He WDs were discovered observationally within the last few years. These observations have exposed an astrophysical puzzle: the sequence of He WDs terminates early compared to the sequence of the commonplace carbon-oxygen-core WDs, so that there is a surprising dearth of observable faint He WDs. This puzzle has motivated us to explore the properties of the super-dense region of the helium phase diagram which determines the properties of the cores of helium white dwarves. At the relevant densities and temperatures, the helium atoms are completely ionized, and we argue the helium nuclei form a Bose-Einstein condensate. The properties of this exotic quantum liquid are quite rich, with a novel gapless quasiparticle, and the specific heat of the condensed phase is far smaller than that of an uncondensed plasma. Since the specific heat of the core is an important input for determining the rate of cooling of a WD star, the nuclear condensate might have observable consequences by accelerating He WD cooling.
Host : HET Group
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