Liouvillian Exceptional Points in Quantum Brickwork Circuits

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.

13 pages, 5 figures