Sampling reduced density matrix to extract fine levels of entanglement spectrum and restore entanglement Hamiltonian.

ABSTRACT: The reduced density matrix (RDM) plays a key role in quantum entanglement and measurement, as it allows the extraction of almost all physical quantities related to the reduced degrees of freedom. However, restricted by the degrees of freedom in the environment, the total system size is often limited, let alone the subsystem. To address this challenge, we propose a quantum Monte Carlo scheme with a low technical barrier, enabling precise extraction of the RDM. To demonstrate the power of the method, we present the fine levels of the entanglement spectrum (ES), which is the logarithmic eigenvalues of the RDM. We clearly show the ES for a 1D ladder with a long entangled boundary, and that for the 2D Heisenberg model with a tower of states. Furthermore, we put forward an efficient way to resto

SUBMITTER: Mao BB 

PROVIDER: S-EPMC11933365 | biostudies-literature | 2025 Mar

REPOSITORIES: biostudies-literature