Strategies for optimizing double-bracket quantum algorithms

Fuente: arXiv
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Main Authors: Xiaoyue, Li, Robbiati, Matteo, Pasquale, Andrea, Pedicillo, Edoardo, Wright, Andrew, Carrazza, Stefano, Gluza, Marek
Format: Preprint
Published: 2024
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author Xiaoyue, Li
Robbiati, Matteo
Pasquale, Andrea
Pedicillo, Edoardo
Wright, Andrew
Carrazza, Stefano
Gluza, Marek
author_facet Xiaoyue, Li
Robbiati, Matteo
Pasquale, Andrea
Pedicillo, Edoardo
Wright, Andrew
Carrazza, Stefano
Gluza, Marek
contents Recently double-bracket quantum algorithms have been proposed as a way to compile circuits for approximating eigenstates. Physically, they consist of appropriately composing evolutions under an input Hamiltonian together with diagonal evolutions. Here, we present strategies to optimize the choice of the double-bracket evolutions to enhance the diagonalization efficiency. This can be done by finding optimal generators and durations of the evolutions. We present numerical results regarding the preparation of double-bracket iterations, both in ideal cases where the algorithm's setup provides analytical convergence guarantees and in more heuristic cases, where we use an adaptive and variational approach to optimize the generators of the evolutions. As an example, we discuss the efficacy of these optimization strategies when considering a spin-chain Hamiltonian as the target. To propose algorithms that can be executed starting today, fully aware of the limitations of the quantum technologies at our disposal, we finally present a selection of diagonal evolution parametrizations that can be directly compiled into CNOTs and single-qubit rotation gates. We discuss the advantages and limitations of this compilation and propose a way to take advantage of this approach when used in synergy with other existing methods.
format Preprint
id arxiv_https___arxiv_org_abs_2408_07431
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Strategies for optimizing double-bracket quantum algorithms
Xiaoyue, Li
Robbiati, Matteo
Pasquale, Andrea
Pedicillo, Edoardo
Wright, Andrew
Carrazza, Stefano
Gluza, Marek
Quantum Physics
Optimization and Control
Recently double-bracket quantum algorithms have been proposed as a way to compile circuits for approximating eigenstates. Physically, they consist of appropriately composing evolutions under an input Hamiltonian together with diagonal evolutions. Here, we present strategies to optimize the choice of the double-bracket evolutions to enhance the diagonalization efficiency. This can be done by finding optimal generators and durations of the evolutions. We present numerical results regarding the preparation of double-bracket iterations, both in ideal cases where the algorithm's setup provides analytical convergence guarantees and in more heuristic cases, where we use an adaptive and variational approach to optimize the generators of the evolutions. As an example, we discuss the efficacy of these optimization strategies when considering a spin-chain Hamiltonian as the target. To propose algorithms that can be executed starting today, fully aware of the limitations of the quantum technologies at our disposal, we finally present a selection of diagonal evolution parametrizations that can be directly compiled into CNOTs and single-qubit rotation gates. We discuss the advantages and limitations of this compilation and propose a way to take advantage of this approach when used in synergy with other existing methods.
title Strategies for optimizing double-bracket quantum algorithms
topic Quantum Physics
Optimization and Control
url https://arxiv.org/abs/2408.07431