标题： 一种为表现出普遍自旋物理的材料推导特定于材料的自旋浴模型描述的方法（用于NISQ设备的模拟） 显示英文标题

标题： A method to derive material-specific spin-bath model descriptions of materials displaying prevalent spin physics (for simulation on NISQ devices)

摘要： 磁性与自旋物理是真正的量子力学效应，其描述通常需要多参考方法，并且常常隐藏于量子化学中分子的标准描述之中。 在这项工作中，我们提出了描述分子和固体中自旋物理的双重方法。 首先，我们提出了一种方法，该方法识别单粒子基，在此基中给定的一组轨道等价于具有低能显著自旋物理的模型和材料中的自旋自由度。我们引入了衡量基轨道自旋相似特性的度量，优化该度量可得到包含最佳自旋相似基轨道的基。 其次，我们演示了一种扩展的施赖弗-沃尔夫变换方法，用于推导作用于希尔伯特空间子空间上的有效哈密顿量，其中自旋类似轨道中电子密度的电荷自由度被积分消去。这种方法随后为系统提供了有效的自旋浴哈密顿量描述。这种扩展的施赖弗-沃尔夫变换适用于广泛的哈密顿量，并已在本工作中用于模型哈密顿量以及分子溴化铬的活性空间哈密顿量。 显示英文摘要

摘要： Magnetism and spin physics are true quantum mechanical effects and their description usually requires multi reference methods and is often hidden in the standard description of molecules in quantum chemistry. In this work we present a twofold approach to the description of spin physics in molecules and solids. First, we present a method that identifies the single-particle basis in which a given subset of the orbitals is equivalent to spin degrees of freedom for models and materials which feature significant spin physics at low energies. We introduce a metric for the spin-like character of a basis orbital, of which the optimization yields the basis containing the optimum spin-like basis orbitals. Second, we demonstrate an extended Schrieffer-Wolff transformation method to derive the effective Hamiltonian acting on the subspace of the Hilbert space in which the charge degree of freedom of electron densities in the spin-like orbitals is integrated out. The method then yields an effective spin-bath Hamiltonian description for the system. This extended Schrieffer-Wolff transformation is applicable to a wide range of Hamiltonians and has been utilized in this work for model Hamiltonians as well as the active space Hamiltonian of molecular chromium bromide.