AC conductivity of non-equilibrium warm dense gold

Summary form only given. In this paper we will present results of a new study on AC conductivity of non-equilibrium warm dense gold. In the experiment, freestanding 30nm-thick gold foils are excited by 400nm, 45fs (FWHM) laser pulses to energy densities up to ∼4MJ/kg. Temporal evolution in AC conductivity of the resulting state is determined from simultaneous measurements of reflection and transmission of a chirped pulse probe at 800nm. This yields two important benchmarks for comparison with theory. The conductivity value at the end of the femtosecond laser pulse is a measure of its dependence on electron temperature as the ions remain cold. Subsequent changes then provide a measure of conductivity as a function of both electron and ion temperatures as thermal equilibration between electron and ion progresses. These data are compared with ab-initio quantum simulations.