aiqbench analysis
This study challenges the assumption that slow-evolving macroscopic quantities in quantum many-body systems can always be consistently monitored, revealing that fluctuations generally fail this criterion under Gaussian weak measurements. The research identifies specific regimes where consistency is preserved, such as at infinite temperature, critical points, or in semiclassical systems, while providing an analytical quantification of non-consistency via susceptibility. These findings offer critical insights for researchers designing quantum measurement protocols and analyzing entropy growth in noisy unitary environments.
Can quantum fluctuations be consistently monitored?
arXiv:2603.15753v2 Announce Type: replace Abstract: Recent works on the decoherent histories formalism suggested that slow-evolving macroscopic quantities (extensive sums of local observables) in quantum many-body systems can be consistently monitored: The existence of past measurements does not alter future outcome distribution. Here, for Gaussian weak measurements, we show that fluctuations of macroscopic quantities cannot be consistently monitored in general, in contrast to their intensive mean value. Exceptions include fluctuations at infinite temperature, at critical points, and in semiclassical systems. We analytically quantify non-consistency in terms of susceptibility, and obtain related results on entropy growth under noisy unitary.
Title:Can quantum fluctuations be consistently monitored?
Abstract:Recent works on the decoherent histories formalism suggested that slow-evolving macroscopic quantities (extensive sums of local observables) in quantum many-body systems can be consistently monitored: The existence of past measurements does not alter future outcome distribution. Here, for Gaussian weak measurements, we show that fluctuations of macroscopic quantities cannot be consistently monitored in general, in contrast to their intensive mean value. Exceptions include fluctuations at infinite temperature, at critical points, and in semiclassical systems. We analytically quantify non-consistency in terms of susceptibility, and obtain related results on entropy growth under noisy unitary.
Quantum Physics (quant-ph); Statistical Mechanics (cond-mat.stat-mech)
arXiv:2603.15753 [quant-ph]
(or arXiv:2603.15753v2 [quant-ph] for this version)
https://doi.org/10.48550/arXiv.2603.15753 Focus to learn more arXiv-issued DOI via DataCite
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Full text under the publisher's open licence · 193 words
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