arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2006.01801quant-phcond-mat.str-elhep-lat
收藏

连续矩阵乘积状态的变分优化

Variational optimization of continuous matrix product states

Benoît Tuybens, Jacopo De Nardis, Jutho Haegeman, Frank Verstraete

摘要:

正如矩阵乘积态忠实地代表一维量子自旋系统的基态一样,连续矩阵乘积态(cMPS)也忠实地代表了一维空间中相互作用场论的真空。然而,与量子自旋的情况下,密度矩阵重整化群和相关的矩阵产品状态算法提供了强大的算法优化变分状态,优化cMPS系统与非均匀的外部潜力一直是有问题的。我们解决这个问题,通过构建一个分段线性参数化的底层矩阵值的功能,这使得计算的精确约化密度矩阵无处不在的系统中的高阶泰勒展开。这将变分cMPS问题转化为变分算法,从该变分算法可以精确地计算能量及其向后导数,并且成本与键维度的立方成比例。我们说明了这一点,通过寻找基态的相互作用玻色子在外部的潜力,并通过计算边界或Casimir能量修正的连续多体系统的开放边界条件。

英文摘要:

Just as matrix product states represent ground states of one-dimensional quantum spin systems faithfully, continuous matrix product states (cMPS) provide faithful representations of the vacuum of interacting field theories in one spatial dimension. Unlike the quantum spin case however, for which the density matrix renormalization group and related matrix product state algorithms provide robust algorithms for optimizing the variational states, the optimization of cMPS for systems with inhomogeneous external potentials has been problematic. We resolve this problem by constructing a piecewise linear parameterization of the underlying matrix-valued functions, which enables the calculation of the exact reduced density matrices everywhere in the system by high-order Taylor expansions. This turns the variational cMPS problem into a variational algorithm from which both the energy and its backwards derivative can be calculated exactly and at a cost that scales as the cube of the bond dimension. We illustrate this by finding ground states of interacting bosons in external potentials, and by calculating boundary or Casimir energy corrections of continuous many-body systems with open boundary conditions.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑