Theory of the correlated quantum Zeno effect in a monitored qubit dimer
Year: 2026
Authors: Zeni S., Chakraborty G., Romito A., Biella A.
Autors Affiliation: Univ Trento, Pitaevskii BEC Ctr, CNR INO, I-38123 Trento, Italy; Univ Trento, Dipartimento Fis, I-38123 Trento, Italy; eXact Lab Srl Janas Project, Via Francesco Crispi 56, I-34126 Trieste, Italy; Univ Lancaster, Dept Phys, Lancaster LA1 4YB, England; Trento Inst Fundamental Phys & Applicat, INFN TIFPA, I-38123 Trento, Italy.
Abstract: We theoretically investigate the stochastic dynamics of two qubits subject to one- and two-site correlated continuous weak measurements. When measurements dominate over the local unitary evolution, the system’s dynamics is constrained and part of the physical Hilbert space becomes inaccessible: a typical signature of the quantum Zeno (QZ) effect. In this work, we show how the competition between these two measurement processes gives rise to two distinct QZ regimes, which we dubbed standard and correlated, characterized by a different topology of the allowed region of the physical Hilbert space, being a simply and nonsimply connected domain, respectively. We develop a theory based on a stochastic Gutzwiller ansatz for the wave function that is able to capture the structure of the phase diagram. Finally we show how the two QZ regimes are intimately connected to the topology of the flow of the underlying non-Hermitian Hamiltonian governing the no-click evolution.
Journal/Review: PHYSICAL REVIEW A
Volume: 113 (6) Pages from: 62424-1 to: 62424-12
More Information: We thank Rosario Fazio, Marcello Dalmonte, Philipp Hauke, Alessandro Roggero, and Oded Zilberberg for inspiring discussions. A.B. acknowledges financial support from the Provincia Autonoma di Trento and by the European Union-NextGeneration EU, within PRIN 2022, PNRR M4C2, TANQU Project No. 2022FLSPAJ (CUP Grant No. B53D23005130006). A.R. and G.C. acknowledge support by EPSRC Grant No. EP/W524438/1.KeyWords: ParadoxDOI: 10.1103/x8n3-2fxt
