论文标题
高斯时间相关的变分原理，用于有限温度的Anharmonic晶格动力学
Gaussian time-dependent variational principle for the finite-temperature anharmonic lattice dynamics
论文作者
论文摘要
Anharmonic晶格是相互作用的玻色子多体系统的代表性示例。自洽的谐波近似已被证明是对Anharmonic晶格的平衡特性的多功能性。然而，对此动态特性的研究诉诸于安萨兹，其有效性尚未得到理论上的证明。在这里，我们将时间依赖性变分原理应用，这是一种最近出现的有用工具，用于研究相互作用的多体系统的动态特性，使用高斯州在有限温度下使用高斯州作为变异歧管，在有限温度下的anharmonic lattice Hamiltonian。我们得出了一个分析公式的位置位置相关函数和声子自我能源，证明了自洽谐波近似的动力学ANSATZ。我们在时间依赖的变分原理和非谐晶格哈密顿量之间建立了富有成果的联系，在这两个领域都提供了见解。我们的工作将依赖时间的变分原理的适用性扩大到第一原理晶格汉密尔顿人，并使用完全变分的框架研究了Anharmonic晶格的动力学特性的基础。
The anharmonic lattice is a representative example of an interacting bosonic many-body system. The self-consistent harmonic approximation has proven versatile for the study of the equilibrium properties of anharmonic lattices. However, the study of dynamical properties therewithin resorts to an ansatz, whose validity has not yet been theoretically proven. Here, we apply the time-dependent variational principle, a recently emerging useful tool for studying the dynamic properties of interacting many-body systems, to the anharmonic lattice Hamiltonian at finite temperature using the Gaussian states as the variational manifold. We derive an analytic formula for the position-position correlation function and the phonon self-energy, proving the dynamical ansatz of the self-consistent harmonic approximation. We establish a fruitful connection between time-dependent variational principle and the anharmonic lattice Hamiltonian, providing insights in both fields. Our work expands the range of applicability of time-dependent variational principle to first-principles lattice Hamiltonians and lays the groundwork for the study of dynamical properties of the anharmonic lattice using a fully variational framework.
