A circuit-differentiation framework for Green's functions on quantum computers

Fuente: arXiv
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Autores principales: Piccinelli, Samuele, Tacchino, Francesco, Tavernelli, Ivano, Carleo, Giuseppe
Formato: Preprint
Publicado: 2025
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author Piccinelli, Samuele
Tacchino, Francesco
Tavernelli, Ivano
Carleo, Giuseppe
author_facet Piccinelli, Samuele
Tacchino, Francesco
Tavernelli, Ivano
Carleo, Giuseppe
contents We propose a general framework for computing Retarded Green's Functions (RGFs) on quantum computers by recasting their evaluation as a problem of circuit differentiation. Our proposal is based on real-time evolution and specifically designed circuit components, which we refer to as circuit perturbations, acting as a direct representation of the external perturbative force within the quantum circuit in a linear-response setting. The direct mapping between circuit derivatives and the computation of RGFs enables the use of a broad range of differentiation strategies. We provide two such examples, including a class of stochastic estimators which do not require extra qubit connectivity with respect to the underlying time-evolution operations. We demonstrate our approach on interacting spin and fermionic models, showing that accurate dynamical correlations can be obtained even under realistic noise assumptions. Finally, we outline how our proposal can be tied to efficient gradient-estimation techniques relevant for the fault-tolerant regime.
format Preprint
id arxiv_https___arxiv_org_abs_2505_05563
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A circuit-differentiation framework for Green's functions on quantum computers
Piccinelli, Samuele
Tacchino, Francesco
Tavernelli, Ivano
Carleo, Giuseppe
Quantum Physics
We propose a general framework for computing Retarded Green's Functions (RGFs) on quantum computers by recasting their evaluation as a problem of circuit differentiation. Our proposal is based on real-time evolution and specifically designed circuit components, which we refer to as circuit perturbations, acting as a direct representation of the external perturbative force within the quantum circuit in a linear-response setting. The direct mapping between circuit derivatives and the computation of RGFs enables the use of a broad range of differentiation strategies. We provide two such examples, including a class of stochastic estimators which do not require extra qubit connectivity with respect to the underlying time-evolution operations. We demonstrate our approach on interacting spin and fermionic models, showing that accurate dynamical correlations can be obtained even under realistic noise assumptions. Finally, we outline how our proposal can be tied to efficient gradient-estimation techniques relevant for the fault-tolerant regime.
title A circuit-differentiation framework for Green's functions on quantum computers
topic Quantum Physics
url https://arxiv.org/abs/2505.05563