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Bibliographic Details
Main Authors: Harrow, Aram W., Lowe, Angus
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2403.01018
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author Harrow, Aram W.
Lowe, Angus
author_facet Harrow, Aram W.
Lowe, Angus
contents We study methods to replace entangling operations with random local operations in a quantum computation, at the cost of increasing the number of required executions. First, we consider "space-like cuts" where an entangling unitary is replaced with random local unitaries. We propose an entanglement measure for quantum dynamics, the product extent, which bounds the cost in a procedure for this replacement based on two copies of the Hadamard test. In the terminology of prior work, this procedure yields a quasiprobability decomposition with minimal 1-norm in a number of cases, which addresses an open question of Piveteau and Sutter. As an application, we give an improved algorithm for clustered Hamiltonian simulation. Specifically we show that interactions can be removed at a cost which is exponential in the sum of their strengths times the evolution time, and vanishing in the limit of weak interactions. We also give an improved upper bound on the cost of replacing wires with measure-and-prepare channels using "time-like cuts''. We prove a matching information-theoretic lower bound when estimating output probabilities.
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institution arXiv
publishDate 2024
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spellingShingle Optimal quantum circuit cuts with application to clustered Hamiltonian simulation
Harrow, Aram W.
Lowe, Angus
Quantum Physics
We study methods to replace entangling operations with random local operations in a quantum computation, at the cost of increasing the number of required executions. First, we consider "space-like cuts" where an entangling unitary is replaced with random local unitaries. We propose an entanglement measure for quantum dynamics, the product extent, which bounds the cost in a procedure for this replacement based on two copies of the Hadamard test. In the terminology of prior work, this procedure yields a quasiprobability decomposition with minimal 1-norm in a number of cases, which addresses an open question of Piveteau and Sutter. As an application, we give an improved algorithm for clustered Hamiltonian simulation. Specifically we show that interactions can be removed at a cost which is exponential in the sum of their strengths times the evolution time, and vanishing in the limit of weak interactions. We also give an improved upper bound on the cost of replacing wires with measure-and-prepare channels using "time-like cuts''. We prove a matching information-theoretic lower bound when estimating output probabilities.
title Optimal quantum circuit cuts with application to clustered Hamiltonian simulation
topic Quantum Physics
url https://arxiv.org/abs/2403.01018