Theory of Nuclear Matter for Neutron Stars and ... - Graduate Physics
Theory of Nuclear Matter for Neutron Stars and ... - Graduate Physics
Theory of Nuclear Matter for Neutron Stars and ... - Graduate Physics
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Appendix BJEL thermodynamic integrationTo compute the properties <strong>of</strong> finite-temperature matter, it is necessary to calculate the Fermiintegrals F 1/2 <strong>and</strong> F 3/2 . Directly calculating these integrals by usual integral methods is notadvisable <strong>for</strong>applicationslike hydrodynamics, which require ahighdegree<strong>of</strong>thermodynamicconsistency. The approach we adopt is due to Johns, Ellis & Lattimer[12] (hereafter referredtoasJEL),whichisamodification<strong>of</strong>alessaccuratescheme originatedbyEggleton, Faulkner& Flannery[8]. These approaches involve polynomial interpolations <strong>for</strong> arbitrary degeneracy<strong>and</strong> relativity. However, in the finite-range model, nucleons are treated non-relativistically,so the interpolation method can be considerably simplified from the general case.The degeneracy parameter Ψ, <strong>and</strong> an associated variable f, are defined in terms <strong>of</strong> thechemical potential <strong>and</strong> temperature assuch thatΨ = µ−VT= 2√f ′ = dfdΨ =1+ f a +ln √1+f/a−1√1+f/a+1,f√1+f/a.(B.1)(B.2)In the above, a is a fitting parameter <strong>and</strong> is given in table B. The Fermi integrals areexpressed as polynomials in f with additional parameters p m , where m = 0...M, that arefixed by the requirements <strong>of</strong> yielding exact results <strong>for</strong> the pressure, energy <strong>and</strong> entropy inthe extremely degenerate <strong>and</strong> non-degenerate limits or by fitting intermediate results. Using116