2025/12/08 by Alberto J. B. Rosal, Patrick P. Potts, Rosal, Alberto J. B. +3
Computer Science · Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #FOS: Physical sciences #Quantum Information and Cryptography #Quantum Physics (quant-ph) #quant-ph #stochastic dynamics and bifurcation
paper · pdf · doi:10.48550/arxiv.2512.08085
published as Phys. Rev. A 114, 012215 (2026)
openalex publication_date 2025/12/08 · openalex created_date 2025/12/11 · arxiv created 2026/06/28 · openalex updated_date 2026/07/28 · arxiv updated 2026/07/31
Feedback uses past detection outcomes to dynamically modify a quantum system and is central to quantum control. These outcomes can be stored in a memory, defined as a stochastic function of past measurements. In this work, we investigate the main properties of a general memory function subject to arbitrary feedback dynamics. We show that the memory can be treated as a classical system coupled to the monitored quantum system, and that their joint evolution is described by a hybrid bipartite state. This framework allows us to introduce information-theoretic measures that quantify the correlations between the system and the memory. Furthermore, we develop a general framework to characterize the statistics of the memory -- such as moments, cumulants, and correlation functions -- which can be applied both to general feedback-control protocols and to monitored systems without feedback. As an application, we analyze feedback schemes based on detection events in a two-level system coupled to a thermal bath, focusing on protocols that stabilize either the excited-state population or Rabi oscillations against thermal dissipation.