Wigner Path Integral Representation of the Density of States. Monte Carlo Simulation of Plasma Media.

A new phase space path integral representation of quantum density of states (DOS) was derived for a strongly coupled plasma media representing hydrogen plasma and two-component Coulomb system with uniformly distributed in space uncorrelated positive charges (“protons”) simulating a neutralizing background (“OCP”). A path integral Monte Carlo approach was used for the calculation of DOS, energy and momentum distribution functions as well as spin–resolved radial distribution functions (RDFs). The RDFs for electrons with the same spin projection revealed exchange–correlation cavities. For a two-component hydrogen plasma (TCP) the Coulomb attraction results in the appearance of high peaks on the proton–electron RDFs at small interparticle distances, while for the “OCP” the analogous RDFs demonstrate an unexpected significant drop arising due to a three–particle effect caused by the electron repulsion preventing for any two electrons to be in the vicinity of any uncorrelated charge. At negative plasma energy the “OCP” DOS is a fast-decaying function, while in hydrogen plasma at a temperature of the order of 1 \(\textrm{Ry} = 0.5\text {Ha}\approx 13.6\) eV the DOS shows a well-pronounced peak related to the bound states. Quantum effects make momentum distribution functions non-maxwellian with a power-law high-momentum asymptotics (“quantum tails”) even under the condition of thermodynamic equilibrium.