Demonstrating Quantum Microscopic Reversibility Using Coherent States of Light

Abstract

The principle of microscopic reversibility lies at the core of fluctuation theorems, which have extended our understanding of the second law of thermodynamics to the statistical level. In the quantum regime, however, this elementary principle should be amended as the system energy cannot be sharply determined at a given quantum phase space point. In this Letter, we propose and experimentally test a quantum generalization of the microscopic reversibility when a quantum system interacts with a heat bath through energy-preserving unitary dynamics. Quantum effects can be identified by noting that the backward process is less likely to happen in the existence of quantum coherence between the system's energy eigenstates. The experimental demonstration has been realized by mixing coherent and thermal states in a beam-splitter, followed by heterodyne detection in an optical setup. We verify that the quantum modification for the principle of microscopic reversibility is critical in the low-temperature limit, while the quantum-to-classical transition is observed as the temperature of the thermal field gets higher.

6+3 pages

References in corpus (6)

• Fluctuation theorems: Work is not an observable
• Irreversible entropy production, from quantum to classical
• Experimental nonclassicality of single-photon-added thermal light states
• Test of Jarzynski and Crooks fluctuation relations in an electronic system
• Experimental Validation of Fully Quantum Fluctuation Theorems Using Dynamic Bayesian Networks
• Quantum Fluctuation Theorem under Continuous Measurement and Feedback

Cited by in corpus (5)

• Experimental signature of initial quantum coherence on entropy production
• Stochastic quantum trajectories demonstrate the Quantum Zeno Effect in open spin 1/2, spin 1 and spin 3/2 systems
• Experimental demonstration of generalized quantum fluctuation theorems in the presence of coherence
• Evidence of genuine quantum effects in nonequilibrium entropy production
• Energy exchange statistics and fluctuation theorem for non-thermal asymptotic states