Quantifying Athermality and Quantum Induced Deviations from Classical Fluctuation Relations

In recent years, a quantum information theoretic framework has emerged for incorporating non-classical phenomena into fluctuation relations. Here, we elucidate this framework by exploring deviations from classical fluctuation relations resulting from the athermality of the initial thermal system and quantum coherence of the system’s energy supply. In particular, we develop Crooks-like equalities for an oscillator system which is prepared either in photon added or photon subtracted thermal states and derive a Jarzynski-like equality for average work extraction. We use these equalities to discuss the extent to which adding or subtracting a photon increases the informational content of a state, thereby amplifying the suppression of free energy increasing process. We go on to derive a Crooks-like equality for an energy supply that is prepared in a pure binomial state, leading to a non-trivial contribution from energy and coherence on the resultant irreversibility. We show how the binomial state equality fits in relation to a previously derived coherent state equality and offers a richer feature-set.

Emission spectrum for a multi-photon Ξ-type three-level atom driven by a binomial field with nonlinearities

A treatment of a multi-photon Ξ-type three-level atom interacting with a single-mode field in a cavity, taking explicitly the existence of forms of nonlinearities of both the field and the intensity-dependent atom–field coupling into account. Analytical expressions of the emission spectrum are presented using the dressed states of the system. The characteristics of the emission spectrum, considering the field to be initially in a binomial state, are exhibited. The effects of the photon multiplicities, mean number of photons, detuning, and the nonlinearities on the spectrum are investigated.