The non-equilibrium structure in warm dense matter

Powerful femtosecond pump lasers and femtosecond x-ray probe beams created by free electron lasers make it possible to create and diagnose strongly correlated states of matter in which the electron and ion Wigner distribution functions are of a strongly non-equilibrium type.
We therefore present a quantum theory for the dynamic structure factors in just such non-equilibrium, correlated, two-component systems.
To make our theory applicable for x-ray scattering as in equilibrium, a generalized Chihara decomposition for the total electron structure factor in non-equilibrium is derived. Examples are given and the influence of correlations and exchange on the structure and the x-ray scattering spectrum are discussed for a model non-equilibrium distribution, as often encountered during laser heating of materials, as well as for two-temperature systems.