Measurement-filter control of Zeno and anti-Zeno switching in finite-memory reservoirs
Phys. Rev. A 114, 032208 – Published 11 September, 2026
DOI: https://doi.org/10.1103/rj6j-yd42
Abstract
We formulate Zeno and anti-Zeno dynamics in a finite-memory reservoir as a time-domain measurement-filter problem. A two-level system exchanges an excitation with a finite chain of damped memory modes and is subjected to repeated partial, nonselective measurements. In the weak-coupling limit, the population decay rate is written as an overlap between a finite reservoir memory kernel and a measurement-dependent filter. For any finite chain, this separation gives a compact expression that connects pulsed and continuous monitoring while retaining correlations across successive measurement intervals. When all memory-mode frequencies are tuned to the two-level transition, a single lossy mode gives monotonic Zeno suppression, whereas two modes form the smallest chain that can produce anti-Zeno-to-Zeno switching without an externally imposed onsite detuning. Exact stroboscopic Liouvillian calculations verify the analytic filter prediction and quantify finite-coupling corrections. For longer chains, the response is controlled by the frequencies, lifetimes, and boundary weights of the memory poles rather than by chain length alone.