A multisite decomposition of the tensor network path integrals

Journal Article · 09 January 2022 · Journal of Chemical Physics

DOI: https://doi.org/10.1063/5.0073234 · OSTI ID:1978989

Bose, Amartya  ^[1]; Walters, Peter L.  ^[2]

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1. Princeton University, NJ (United States); Princeton Univ., NJ (United States)
2. University of California, Berkeley, CA (United States)

Tensor network decompositions of path integrals for simulating open quantum systems have recently been proven to be useful. However, these methods scale exponentially with the system size. This makes it challenging to simulate the non-equilibrium dynamics of extended quantum systems coupled with local dissipative environments. In this work, we extend the tensor network path integral (TNPI) framework to efficiently simulate such extended systems. The Feynman–Vernon influence functional is a popular approach used to account for the effect of environments on the dynamics of the system. In order to facilitate the incorporation of the influence functional into a multisite framework (MS-TNPI), we combine a matrix product state (MPS) decomposition of the reduced density tensor of the system along the sites with a corresponding tensor network representation of the time axis to construct an efficient 2D tensor network. The 2D MS-TNPI network, when contracted, yields the time-dependent reduced density tensor of the extended system as an MPS. The algorithm presented is independent of the system Hamiltonian. We outline an iteration scheme to take the simulation beyond the non-Markovian memory introduced by solvents. Applications to spin chains coupled to local harmonic baths are presented; we consider the Ising, XXZ, and Heisenberg models, demonstrating that the presence of local environments can often dissipate the entanglement between the sites. We discuss three factors causing the system to transition from a coherent oscillatory dynamics to a fully incoherent dynamics. The MS-TNPI method is useful for studying a variety of extended quantum systems coupled with solvents.

• Research Organization: Princeton University, NJ (United States)
• Sponsoring Organization: USDOE Office of Science (SC); Miller Institute for Basic Research in Science
• Grant/Contract Number: SC0019394
• OSTI ID: 1978989
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 2 Vol. 156; ISSN 0021-9606
• Publisher: American Institute of Physics (AIP)Copyright Statement
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
Feynman path integral
Heisenberg model
Ising spins
density-matrix
matrix product state
open quantum systems
quantum dissipation
quantum mechanical systems and processes
statistical mechanics models
tensor network theory