Anomalous waiting-time distributions in postselection-free quantum many-body dynamics under continuous monitoring

Abstract:We investigate waiting-time distributions (WTDs) of quantum jumps in continuously monitored quantum many-body systems, whose unconditional dynamics lead to the trivial infinite-temperature state. We demonstrate that the WTD of a half-chain subsystem exhibits an anomalous tail, markedly deviating from the Poissonian distribution in stark contrast to that of the whole system. By analyzing the spectral properties of the superoperator $\mathscr L_0$, which is defined by removing the jump terms associated with the half-chain subsystem from the full Liouvillian, we find that the long-time behavior with the anomalous tail of the half-chain WTD is governed by the eigenvalue $\lambda_0\:(<0)$ with the largest real part. We further reveal a qualitative change in the system-size dependence of $\lambda_0$ as a function of the measurement strength: for sufficiently weak measurement, $\lambda_0$ decreases proportionally to the system size, while for strong measurement, $\lambda_0$ scales independently of the system size, signaling the persistence of the anomalous half-chain WTD in the thermodynamic limit. The WTD is extracted solely from the spacetime record of quantum jumps $\{t_i,x_i\}$ and can be experimentally accessed without postselection. Our work establishes a spectral framework for understanding nontrivial WTDs in subsystems of monitored quantum dynamics and provides a novel diagnostics to assess many-body effects on WTDs.

Statistical Mechanics (cond-mat.stat-mech); Quantum Gases (cond-mat.quant-gas); Quantum Physics (quant-ph)

arXiv:2604.00358 [cond-mat.stat-mech]

(or arXiv:2604.00358v2 [cond-mat.stat-mech] for this version)

https://doi.org/10.48550/arXiv.2604.00358 Focus to learn more arXiv-issued DOI via DataCite

https://doi.org/10.1088/2058-9565/ae9183 Focus to learn more DOI(s) linking to related resources

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