Thermodynamic Properties of Correlated Strongly Degenerate Plasmas

An efficient numerical approach to equilibrium properties of strongly coupled systems which include a subsystem of fermionic quantum particles and a subsystem of classical particles is presented. It uses an improved path integral representation of the many-particle density operator and allows to describe situations of strong coupling and strong degeneracy, where analytical theories fail. A novel numerical method is developed, which allows to treat degenerate systems with full account of the spin scatistics. Numerical results for thermodynamic properties such as internal energy, pressure and pair correlation functions are presented over a wide range of degeneracy parameter.Comment: 8 pages, 4 figures, uses sprocl.sty (included) to be published in "Progress in Nonequilibrium Green's functions", M. Bonitz (Ed.), World Scientific 200

Strict derivation of angular-averaged Ewald potential

In this work we strictly derive an angular-averaged Ewald potential suitable for numerical simulations of disordered Coulomb systems. The potential was first introduced by E. Yakub and C. Ronchi without strict mathematical justification. Two methods are used to find the coefficients of the series expansion of the potential: based on the Euler-Maclaurin and Poisson summation formulas. The expressions for each coefficient is represented as a finite series containing derivatives of Jacobi theta functions. We also demonstrate the formal equivalence of the Poisson and Euler-Maclaurin summation formulas in the three-dimensional case. The effectiveness of the angular-averaged Ewald potential is shown by the example of calculating the Madelung constant for a number of crystal lattices

Pressure of Coulomb systems with volume-dependent long-range potentials

In this work, we consider the pressure of Coulomb systems, in which particles interact via a volume-dependent potential (in particular, the Ewald potential). We confirm that the expression for virial pressure should be corrected in this case. We show that the corrected virial pressure coincides with the formula obtained by differentiation of free energy if the potential energy is a homogeneous function of particle coordinates and a cell length. As a consequence, we find out that the expression for pressure in the recent paper by J. Liang \textit{et al.} [\href{https://doi.org/10.1063/5.0107140}{J. Chem. Phys. \textbf{157}, 144102 (2022)}] is incorrect