paper

Bounds on quantum Fisher information and uncertainty relations for thermodynamically conjugate variables

arXiv:2511.05042 · doi:10.21468/SciPostPhys.20.6.177

Abstract

Uncertainty relations represent a foundational principle in quantum mechanics, imposing inherent limits on the precision with which \textit{mechanically} conjugate variables such as position and momentum can be simultaneously determined. This work establishes analogous relations for \textit{thermodynamically} conjugate variables -- specifically, a classical intensive parameter and its corresponding extensive quantum operator -- in equilibrium states. We develop a framework to derive a rigorous thermodynamic uncertainty relation for such pairs, where the uncertainty of the classical parameter is quantified by its quantum Fisher information . The framework is based on an exact integral representation that relates to the autocorrelation function of operator . From this representation, we derive a tight upper bound for the quantum Fisher information, which yields a thermodynamic uncertainty relation: with and is the system temperature. The result establishes a fundamental precision limit for quantum sensing and metrology in thermal systems, directly connecting it to the thermodynamic properties of linear response and fluctuations.

14 pages, 3 figures

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