Coherence Effects and Neutrino Pair Bremsstrahlung in Neutron Stars

We calculate the rate of energy radiation by bremsstrahlung of neutrino pairs by baryons in neutron stars employing a transport model in which neutrinos couple to baryons with spectral width. The coherence effects, which are included by computing the self energies with fully dressed propagators, lead to the Landau-Pomeranchuk-Migdal suppression of the neutrino emission rates in the soft neutrino and high temperature limit. A microscopic evaluation of the bremsstrahlung rate by neutrons is carried out using the Brueckner theory of nuclear matter at finite temperatures.