标题： 有限温度下二维软核玻色子的超固体相 显示英文标题

标题： Supersolid phase in two-dimensional soft-core bosons at finite temperature

摘要： 研究了二维软核玻色子的超固体相，采用自洽的哈特里-福克方法和量子蒙特卡罗方法。 首先通过平均场方法构建了一个有限温度下的近似相图，随后通过精确的路径积分模拟验证了该相图，从而实现了对各种相的微观表征。 通过超流密度以及与位置和取向有序相关的关联函数的长程行为来分析超流和熔化/冻结转变，这与贝雷津斯基-科斯特利茨-汤勒斯转变的一般图像一致。 在低温下识别出一个广泛的区域，其中存在超固体相，它将均匀超流相与正常准晶体相分离开来。 此外，在正常固体相和流体相之间的狭窄区域内，发现了一种潜在的中间六角相，具有准长程取向有序。 这些发现确立了自洽的哈特里-福克理论（超越局域密度近似）作为一种有效的工具，与计算密集型的量子蒙特卡罗模拟互补，用于研究超固体相的熔化以及玻色子系统中六角超流相可能的出现，这些系统具有各种相互作用势。 显示英文摘要

摘要： The supersolid phase of soft-core bosons in two dimensions is investigated using the self-consistent Hartree-Fock and quantum Monte Carlo methods. An approximate phase diagram at finite temperatures is initially constructed using the mean-field approach, which is subsequently validated through precise path-integral simulations, enabling a microscopic characterization of the various phases. Superfluid and melting/freezing transitions are analyzed through the superfluid density and the long-range behavior of correlation functions associated with positional and orientational order, in accordance with the general picture of Berezinskii-Kosterlitz-Thouless transitions. A broad region at low temperatures is identified where the supersolid phase exists, separating the uniform superfluid phase from the normal quasi-crystal phase. Additionally, a potential intermediate hexatic phase with quasi long-range orientational order is identified in a narrow region between the normal solid and fluid phases. These findings establish self-consistent Hartree-Fock theory beyond the local density approximation as an effective tool, complementary to computationally intensive quantum Monte Carlo simulations, for investigating the melting of the supersolid phase and the possible emergence of the hexatic superfluid phase in bosonic systems with various interaction potentials.