Local Matrix Product Operators: Canonical Form, Compression, & Control Theory

Abstract

We present a new method for compressing matrix product operators (MPOs) which represent sums of local terms, such as Hamiltonians. Just as with area law states, such local operators may be fully specified with a small amount of information per site. Standard matrix product state (MPS) tools are ill-suited to this case, due to extensive Schmidt values that coexist with intensive ones, and Jordan blocks in the transfer matrix. We ameliorate these issues by introducing an "almost Schmidt decomposition" that respects locality. Our method is "$\epsilon$-close" to the accuracy of MPS-based methods for finite MPOs, and extends seamlessly to the thermodynamic limit, where MPS techniques are inapplicable. In the framework of control theory, our method generalizes Kung's algorithm for model order reduction. Several examples are provided, including an all-MPO version of the operator recursion method (Lanczos algorithm) directly in the thermodynamic limit. All results are accompanied by practical algorithms, well-suited for the large MPOs that arise in DMRG for long-range or quasi-2D models.

31 pages, 3 figures, 6 practical algorithms; v2: corrected algorithm for triangular iMPO with unit cells; v3: added an Appendix and several corrections suggested by reviewers. v3 is essentially identical to the journal version

References in corpus (10)

• The density-matrix renormalization group in the age of matrix product states
• Matrix product states represent ground states faithfully
• From density-matrix renormalization group to matrix product states
• Entropy scaling and simulability by Matrix Product States
• A Universal Operator Growth Hypothesis
• Time-evolving a matrix product state with long-ranged interactions
• Tangent-space methods for uniform matrix product states
• Infinite density matrix renormalization group for multicomponent quantum Hall systems
• Generic Construction of Efficient Matrix Product Operators
• Finite automata for caching in matrix product algorithms

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