Monte Carlo simulations of the charged boson fluid at T=0.

Abstract

The diffusion Monte Carlo (DMC) method is used to analyze various properties of the three-dimensional plasma of charged bosons in the homogeneous fluid regime, over the density range 1\ensuremath{\le}${\mathit{r}}_{\mathit{s}}$\ensuremath{\le}160 extending from the so-called uniform limit (${\mathit{r}}_{\mathit{s}}$1) to the crystalline phase (${\mathit{r}}_{\mathit{s}}$\ensuremath{\gtrsim}160). The data on the static density response function \ensuremath{\chi}(k) extend to intermediate and high wave number k the work of Sugiyama, Bowen, and Alder [Phys. Rev. B 46, 13 042 (1992)] and allow us to extract the static local-field factor G(k) for exchange and correlation. The DMC results for the momentum distribution n(k) show that the condensate fraction decreases with increasing coupling strength from 83% at ${\mathit{r}}_{\mathit{s}}$=1 to less than 1% at ${\mathit{r}}_{\mathit{s}}$=160. We also present results for the ground-state energy ${\mathit{E}}_{\mathit{g}}$(${\mathit{r}}_{\mathit{s}}$) and for the structure factor S(k). The results for ${\mathit{E}}_{\mathit{g}}$(${\mathit{r}}_{\mathit{s}}$), n(k), and \ensuremath{\chi}(k) are summarized in analytic interpolation formulas embodying the known asymptotic behaviors. A rigorous upper bound on the plasmon dispersion curve is obtained from the DMC data through a sum-rule argument. \textcopyright{} 1996 The American Physical Society.