2025/08/21 by Mia Stamatova, Vlatko Vedral, Stamatova, Mia +1
Physics and Astronomy · Computer Science · #Advanced Thermodynamics and Statistical Mechanics #Quantum many-body systems #Quantum Information and Cryptography
paper · pdf · doi:10.48550/arxiv.2508.15728
We propose a novel witness of temporal quantum entanglement using the imaginary component of the complex heat capacity - a measurable thermodynamic quantity in temperature-modulated calorimetry. By establishing a direct correspondence between complex heat capacity and the pseudo-density matrix formalism, our approach enables the characterisation of both spatial and temporal quantum correlations without demanding additional state-level manipulation beyond initial tomography. We analytically demonstrate this connection for an open quantum system modelled by a qubit coupled to a thermal bath, and show how both pseudo-density matrix negativity and violations of a temporal CHSH inequality emerge as indicators of non-classical temporal correlations. We further identify bounds on the imaginary heat capacity that guarantee temporal entanglement, providing an experimentally accessible criterion at the macroscopic scale. This framework offers a feasible route for probing temporal quantum effects in condensed-matter systems and opens a viable path toward experimental realisation.