Quantum Fisher Information and Uncertainty Relations

Paolo Gibilisco, Tommaso Isola

Paolo Gibilisco, Tommaso Isola

Paolo Gibilisco, Daniele Imparato, Tommaso Isola

Paolo Gibilisco, Daniele Imparato, Tommaso Isola

Paolo Gibilisco, Fumio Hiai, Dėnes Petz

In this paper, the relation between quantum covariances and quantum Fisher informations is studied. This study is applied to generalize a recently proved uncertainty relation based on quantum Fisher information. The proof given here considerably simplifies the previously proposed proofs and leads to more general inequalities.

Ye-Ming Meng, Zhe-Yu Shi

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 $θ$ and its corresponding extensive quantum operator $\hat{O}$ -- in equilibrium states. We develop a framework to derive a rigorous thermodynamic uncertainty relation for such pairs, where the uncertainty of the classical parameter $θ$ is quantified by its quantum Fisher information $\mathcal{F}_θ$. The framework is based on an exact integral representation that relates $\mathcal{F}_θ$ to the autocorrelation function of operator $\hat{O}$. From this representation, we derive a tight upper bound for the quantum Fisher information, which yields a thermodynamic uncertainty relation: $Δθ\,\overline{ΔO} \ge k_\text{B}T$ with $\overline{ΔO}\equiv\partial_θ\langle\hat{O}\rangle\,Δθ$ and $T$ 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.