Quantum Simulation of Open Quantum Systems Using Density-Matrix Purification
Abstract
Electronic structure and transport in realistically-sized systems often require an open quantum system (OQS) treatment, where the system is defined in the context of an environment. As OQS evolution is non-unitary, implementation on quantum computers -- limited to unitary operations -- is challenging. We present a general framework for OQSs where the system's density matrix is recast as a wavefunction which can be evolved by unitary transformations. This theory has two significant advantages over conventional approaches: (i) the wavefunction requires only an -qubit, compared to -qubit, bath for an -qubit system and (ii) the purification includes dynamics of any pure-state universe. We demonstrate this method on a two-level system in a zero temperature amplitude damping channel and a two-site quantum Ising model. Quantum simulation and experimental-device results agree with classical calculations, showing promise in simulating non-unitary operations on NISQ quantum devices.
Cite
@article{arxiv.2207.07112,
title = {Quantum Simulation of Open Quantum Systems Using Density-Matrix Purification},
author = {Anthony W. Schlimgen and Kade Head-Marsden and LeeAnn M. Sager-Smith and Prineha Narang and David A. Mazziotti},
journal= {arXiv preprint arXiv:2207.07112},
year = {2022}
}