Quantum Thermodynamics: A Case Study for Emergent Behavior

Jochen Gemmer B, Mathias Michel A, Günter Mahler A

Günter Mahler A, Jochen Gemmer B, Mathias Michel A

Felix C. Binder, Luis Alfonso Correa, Christian Gogolin +2 more

Irene Ada Picatoste, Alessandra Colla, Heinz‐Peter Breuer

Employing a recently developed approach to dynamically emergent quantum thermodynamics, we revisit the thermodynamic behavior of the quantum Otto cycle with a focus on memory effects and strong system-bath couplings. Our investigation is based on an exact treatment of non-Markovianity by means of an exact quantum master equation, modeling the dynamics through the Fano-Anderson model featuring a peaked environmental spectral density. By comparing the results to the standard Markovian case, we find that non-Markovian baths can induce work transfer to the system, and identify specific parameter regions which lead to enhanced work output and efficiency of the cycle. In particular, we demonstrate that these improvements arise when the cycle operates in a frequency interval which contains the peak of the spectral density. This can be understood from an analysis of the renormalized frequencies emerging through the system-bath couplings. Published by the American Physical Society 2024

Sebastian Deffner, Steve Campbell

Tiago Pernambuco, Lucas Chibebe Céleri

We formulate a geometric framework in which physical laws emerge from restricted access to microscopic information. Measurement constraints are modeled as a gauge symmetry acting on density operators, inducing a gauge-reduced space of physically distinguishable states. In the case of quantum thermodynamics, this construction leads to a gauge-invariant formulation in which the invariant entropy admits a stochastic description and satisfies a general detailed fluctuation theorem. From this result, we derive an integrated fluctuation theorem and a Clausius-like inequality that unifies the first and second laws in terms of invariant work and coherent heat. Entropy production is identified with the relative entropy between forward and backward probability measures on the gauge-reduced space of thermodynamic trajectories, revealing irreversibility as a geometric consequence of limited observability. The third law emerges as a singular zero-temperature limit in which thermodynamic orbits collapse and entropy production vanishes. Since the framework applies to arbitrary information constraints, it encompasses energy-based thermodynamics as a particular case of more general measurement scenarios.