2016/09/21 by Paul Erker, Mark T. Mitchison, Ralph Silva +3 · 1 voice · 1 citation
Computer Science · Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #Classical mechanics #Computer science #Measure (data warehouse) #Observable #Open quantum system #Physics #Quantum #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum mechanics #Quantum thermodynamics #Statistical physics #quant-ph
paper · pdf · open access · doi:10.1103/physrevx.7.031022
published in Physical Review X 7(3) (American Physical Society) · Close to published version. 7+5 pages, 5 figures
arxiv published 2016/09/21 · openalex publication_date 2017/08/02 · arxiv created 2017/08/04 · arxiv updated 2017/08/08 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Time remains one of the least well understood concepts in physics, most notably in quantum mechanics. A central goal is to find the fundamental limits of measuring time. One of the main obstacles is the fact that time is not an observable and thus has to be measured indirectly. Here we explore these questions by introducing a model of time measurements that is complete and autonomous. Specifically, our autonomous quantum clock consists of a system out of thermal equilibrium --- a prerequisite for any system to function as a clock --- powered by minimal resources, namely two thermal baths at different temperatures. Through a detailed analysis of this specific clock model, we find that the laws of thermodynamics dictate a trade-off between the amount of dissipated heat and the clock's performance in terms of its accuracy and resolution. Our results furthermore imply that a fundamental entropy production is associated with the operation of any autonomous quantum clock, assuming that quantum machines cannot achieve perfect efficiency at finite power. More generally, autonomous clocks provide a natural framework for the exploration of fundamental questions about time in quantum theory and beyond.