Physical Review Letters
Critical Temperature Shift in Weakly Interacting Bose Gas
V. А. Kashurnikov, Nikolay V. Prokof'ev, Boris V. Svistunov
Abstract
With a high-performance Monte Carlo algorithm we study the interaction-induced shift of the critical point in weakly interacting three-dimensional $|\ensuremath{\psi}{|}^{4}$ theory (which includes quantum Bose gas). In terms of critical density, ${n}_{c}$, mass, $m$, interaction, $U$, and temperature, $T$, this shift is universal: $\ensuremath{\Delta}{n}_{c}(T){\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}\ensuremath{-}Cm}^{3}{T}^{2}U$, the constant $C$ found to be equal to $0.0140\ifmmode\pm\else\textpm\fi{}0.0005$. For quantum Bose gas with the scattering length $a$ this implies $\ensuremath{\Delta}{T}_{c}{/T}_{c}{\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}C}_{0}{\mathrm{an}}^{1/3}$, with ${C}_{0}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1.29\ifmmode\pm\else\textpm\fi{}0.05$.