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Main Authors: Hu, Xi-Dan, Zhang, Dan-Bo
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2406.08338
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author Hu, Xi-Dan
Zhang, Dan-Bo
author_facet Hu, Xi-Dan
Zhang, Dan-Bo
contents Dual-unitary quantum circuits can provide analytic spatiotemporal correlation functions of local operators from transfer matrices, enriching our understanding of quantum dynamics with exact solutions. Nevertheless, a full understanding is still lacking as the case of a non-diagonalizable transfer matrix with exceptional points has less been investigated. In this paper, we give an inverse approach for constructing dual-unitary quantum circuits with exceptional points in the transfer matrices, by establishing relations between transfer matrices and local unitary gates. As a consequence of the coalesce of eigenvectors, the correlation functions exhibit a polynomial modified exponential decay, which is significantly different from pure exponential decay, especially at early stages. Moreover, we point out that the Hamiltonian evolution of a kicked XXZ spin chain can be approximately mapped to a dual-unitary circuit with exceptional points by Trotter decomposition. Finally, we investigate the dynamics approaching and at exceptional points, showing that behaviors of correlation functions are distinct by Laplace transformation.
format Preprint
id arxiv_https___arxiv_org_abs_2406_08338
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Exact Correlation Functions for Dual-Unitary Quantum circuits with exceptional points
Hu, Xi-Dan
Zhang, Dan-Bo
Quantum Physics
Dual-unitary quantum circuits can provide analytic spatiotemporal correlation functions of local operators from transfer matrices, enriching our understanding of quantum dynamics with exact solutions. Nevertheless, a full understanding is still lacking as the case of a non-diagonalizable transfer matrix with exceptional points has less been investigated. In this paper, we give an inverse approach for constructing dual-unitary quantum circuits with exceptional points in the transfer matrices, by establishing relations between transfer matrices and local unitary gates. As a consequence of the coalesce of eigenvectors, the correlation functions exhibit a polynomial modified exponential decay, which is significantly different from pure exponential decay, especially at early stages. Moreover, we point out that the Hamiltonian evolution of a kicked XXZ spin chain can be approximately mapped to a dual-unitary circuit with exceptional points by Trotter decomposition. Finally, we investigate the dynamics approaching and at exceptional points, showing that behaviors of correlation functions are distinct by Laplace transformation.
title Exact Correlation Functions for Dual-Unitary Quantum circuits with exceptional points
topic Quantum Physics
url https://arxiv.org/abs/2406.08338