2025/02/18 by Thales Augusto Barbosa Pinto Silva, David Gelbwaser-Klimovsky, Silva, Thales Augusto Barbosa Pinto +1 · 2 citations
Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Conservation law #Economics #Law and economics #Opinion Dynamics and Social Influence #Physics #Political science #Quantum #Quantum Mechanics and Applications #Quantum mechanics #quant-ph
paper · pdf · doi:10.48550/arxiv.2502.12905
published in arXiv (Cornell University) (Cornell University)
openalex publication_date 2025/02/18 · openalex created_date 2025/02/20 · openalex updated_date 2026/08/05
Quantum fluctuations are fundamental to quantum technologies, affecting quantum computing, sensing, cryptography, and thermodynamics. A paradigmatic example is quantum work, which, for a thermally isolated driven system, is identified with the variation of its energy. Although quantum mechanics provides precise rules for measuring energy and other observables at individual instants of time, it does not provide a standard framework for characterizing the statistics of their variations between two times. This ambiguity has led to competing protocols that can assign different work distributions--and, more generally, different fluctuation statistics--to the same physical process, with consequences for both foundational physics and quantum technologies. In this work, we propose four fundamental criteria that any consistent protocol for measuring energy variations must satisfy, grounded in conservation laws, state independence of the measurement apparatus, the no-signaling principle, and constraints on physical reality. We prove that these criteria uniquely select the two-time quantum observable protocol. We then show that this conclusion extends beyond work and energy to the variation of arbitrary physical observables, including charge, particle number, and momentum. This result has the potential to establish the foundations for measurements of quantum processes, possibly resolving ambiguities in quantum fluctuation measurements. Moreover, it enables the extension of quantum information concepts, such as entanglement and Bell's inequalities, to processes rather than instantaneous observables.