标题： 有限密度和温度下复杂$φ^4$理论的扩展平均场研究 显示英文标题

标题： Extended Mean Field study of complex $φ^4$-theory at finite density and temperature

摘要： 我们回顾扩展平均场理论（EMFT）近似，并将其应用于格点上的复杂标量$\phi^4$理论。 我们研究了由非零化学势$\mu$驱动的玻色凝聚的临界性质，在零温度和非零温度下确定了$(T,\mu)$相图。 结果与所有考虑参数值的最新蒙特卡罗数据非常吻合。 EMFT 可以直接在热力学极限中表述，这使我们能够研究目前技术无法进行蒙特卡罗研究的格点间距。 我们发现 EMFT 近似准确地再现了精确解的许多已知现象，如零温度下的“银焰”行为和有限温度下的维度减少。 显示英文摘要

摘要： We review the Extended Mean Field Theory (EMFT) approximation and apply it to complex, scalar $\phi^4$-theory on the lattice. We study the critical properties of the Bose condensation driven by a nonzero chemical potential $\mu$ at both zero and nonzero temperature and determine the $(T,\mu)$ phase diagram. The results are in very good agreement with recent Monte Carlo data for all parameter values considered. EMFT can be formulated directly in the thermodynamic limit which allows us to study lattice spacings for which Monte Carlo studies are not feasible with present techniques. We find that the EMFT approximation accurately reproduces many known phenomena of the exact solution, like the "Silver Blaze" behavior at zero temperature and dimensional reduction at finite temperature.