Environment-matrix-product operator for boundary-free large-scale quantum many-body simulations

TL;DR

This paper introduces an environment-matrix-product operator method that enables boundary-free, large-scale quantum many-body simulations by iteratively embedding finite systems within semi-infinite environments, reducing finite-size effects.

Contribution

It presents a novel environment MPO construction technique that does not assume homogeneity and allows for long real-time dynamics without boundary reflections.

Findings

Achieves boundary-free large-scale quantum simulations.

Enables long real-time dynamics free from boundary effects.

Reduces finite-size effects in quantum many-body calculations.

Abstract

We propose an alternative to the infinite density-matrix renormalization approach for accessing quantum many-body states within a finite-size calculation that faithfully mimics the thermodynamic limit. Our method constructs environment matrix product operators (MPOs) representing the Hamiltonian of semi-infinite regions surrounding the target system. Starting from the finite-size ground-state MPS, we contract its Hamiltonian representation to generate effective environment MPOs, which are then attached to a renewed finite system in a recursive manner. This iterative embedding drives the system toward a bulk-like state with negligible finite-size effects. The scheme requires no assumption of homogeneity and achieves unprecedentedly long real-time dynamics free from boundary reflections.