Scalable simulation of non-equilibrium quantum dynamics via classically optimised unitary circuits

Fuente: arXiv
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Bibliographic Details
Main Authors: Causer, Luke, Jung, Felix, Mitra, Asimpunya, Pollmann, Frank, Gammon-Smith, Adam
Format: Preprint
Published: 2023
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author Causer, Luke
Jung, Felix
Mitra, Asimpunya
Pollmann, Frank
Gammon-Smith, Adam
author_facet Causer, Luke
Jung, Felix
Mitra, Asimpunya
Pollmann, Frank
Gammon-Smith, Adam
contents The advent of near-term digital quantum computers could offer us an exciting opportunity to investigate quantum many-body phenomena beyond that of classical computing. To make the best use of the hardware available, it is paramount that we have methods that accurately simulate Hamiltonian dynamics for limited circuit depths. In this paper, we propose a method to classically optimise unitary brickwall circuits to approximate quantum time evolution operators. Our method is scalable in system size through the use of tensor networks. We demonstrate that, for various three-body Hamiltonians, our approach produces quantum circuits that can outperform Trotterization in both their accuracy and the quantum circuit depth needed to implement the dynamics, with the exact details being dependent on the Hamiltonian. We also explain how to choose an optimal time step that minimises the combined errors of the quantum device and the brickwall circuit approximation.
format Preprint
id arxiv_https___arxiv_org_abs_2312_14245
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Scalable simulation of non-equilibrium quantum dynamics via classically optimised unitary circuits
Causer, Luke
Jung, Felix
Mitra, Asimpunya
Pollmann, Frank
Gammon-Smith, Adam
Quantum Physics
Strongly Correlated Electrons
The advent of near-term digital quantum computers could offer us an exciting opportunity to investigate quantum many-body phenomena beyond that of classical computing. To make the best use of the hardware available, it is paramount that we have methods that accurately simulate Hamiltonian dynamics for limited circuit depths. In this paper, we propose a method to classically optimise unitary brickwall circuits to approximate quantum time evolution operators. Our method is scalable in system size through the use of tensor networks. We demonstrate that, for various three-body Hamiltonians, our approach produces quantum circuits that can outperform Trotterization in both their accuracy and the quantum circuit depth needed to implement the dynamics, with the exact details being dependent on the Hamiltonian. We also explain how to choose an optimal time step that minimises the combined errors of the quantum device and the brickwall circuit approximation.
title Scalable simulation of non-equilibrium quantum dynamics via classically optimised unitary circuits
topic Quantum Physics
Strongly Correlated Electrons
url https://arxiv.org/abs/2312.14245