标题： 复杂$φ^4$理论在有限密度和温度下的扩展平均场研究 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。 我们研究由非零化学势驱动的玻色凝聚的临界性质$\mu$在零温度和非零温度下的情况，并确定$(T,\mu)$相图。 结果与所有考虑参数值的最新蒙特卡洛数据非常吻合。 EMFT 可以直接在热力学极限下表述，这使我们能够研究目前技术难以进行蒙特卡洛研究的格点间距。 我们发现 EMFT 近似能准确再现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降低。 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.