Really condensed matter: problems in the physics of neutron star crusts and white dwarf interiors - by Tyler Engstrom
Tyler Engstrom Department of Physics, Syracuse University
Host: Jen Schwarz | Contact: Matthias Merkel, email@example.com
Precision measurements of a half-dozen different kinds of astrophysical phenomena can potentially probe a neutron star crust's material properties, including elastic constants, transport coefficients, and equation of state. Condensed matter theory dealing with extreme pressures and huge magnetic fields (~1012-1015 gauss) might thus be tested in this "laboratory." After giving an overview of the phenomena, I will describe two toy models of electrons and nuclei in huge magnetic fields: a nonlinear Thomas-Fermi model of the lowest Landau level, and a nearly free electron model containing magnetic commensurability effects. The former predicts a large shear modulus enhancement compared to the linearly-screened Coulomb crystal, and the latter hints at the existence of stellar layers in which transport anisotropy is reduced, i.e. heat spreading layers. Next we will turn to 3-component accreted crusts and 3-component white dwarfs (in particular, type 1a supernova progenitors). A global genetic search of composition and structure predicts several new astrophysically-relevant crystal structures; these are included in a new, self-consistent coupling of the phase stability and stellar structure problems (for white dwarfs). Equilibrium phase layering diagrams are computed.