Thermal conductivity and impurity scattering in the accreting neutron star crust

We calculate the thermal conductivity of electrons for the strongly correlated multicomponent ion plasma expected in the outer layers of a neutron star's crust, employing a Path Integral Monte Carlo (PIMC) approach. This allows us to isolate the low energy response of the ions and use it to calculate the electron scattering rate and the electron thermal conductivity. We find that the scattering rate is enhanced by a factor 2-4 compared to earlier calculations based on the simpler electron-impurity scattering formalism. This finding impacts the interpretation of thermal relaxation observed in transiently accreting neutron stars, and has implications for the composition and nuclear reactions in the crust that occur during accretion.