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Liouvillian exceptional points in quantum brickwork circuits

Vladislav Popkov1,2 and Mario Salerno3

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Phys. Rev. A 113, 043525 – Published 29 April, 2026

DOI: https://doi.org/10.1103/ksj2-w5cj

Abstract

We demonstrate that Liouvillian exceptional points (LEPs), previously explored only in continuous Lindbladian dynamics, also emerge in discrete brickwork completely positive trace-preserving (CPTP) circuits. By analytically solving a minimal two-qubit brickwork model, we identify the conditions under which discrete-time LEPs arise and show that they retain the hallmark square-root eigenvalue splitting and linear-in-time sensitivity enhancement. These results establish a direct bridge between continuous non-Hermitian physics and discrete quantum-circuit architectures, opening a path toward the realization of exceptional-point-based sensing on near-term quantum processors.

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Phys. Rev. A 113, 043525– Published 29 April, 2026
  • Received 15 October 2025
  • Accepted 14 April 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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