Effective Reconstruction of Expectation Values from Ab Initio Quantum Embedding.

ABSTRACT: Quantum embedding is an appealing route to fragment a large interacting quantum system into several smaller auxiliary "cluster" problems to exploit the locality of the correlated physics. In this work, we critically review approaches to recombine these fragmented solutions in order to compute nonlocal expectation values, including the total energy. Starting from the democratic partitioning of expectation values used in density matrix embedding theory, we motivate and develop a number of alternative approaches, numerically demonstrating their efficiency and improved accuracy as a function of increasing cluster size for both energetics and nonlocal two-body observables in molecular and solid state systems. These approaches consider the N-representability of the resulting expectation v

SUBMITTER: Nusspickel M 

PROVIDER: S-EPMC10210252 | biostudies-literature | 2023 May

REPOSITORIES: biostudies-literature