Experimental challenges and prospects for quantum-enhanced energy conversion: stationary Fano coherence in V-type qutrits interacting with polarized incoherent radiation
Year: 2026
Authors: Donati L., Cataliotti F.S., Gherardini S.
Autors Affiliation: CNR, INO, Largo Enrico Fermi 6, I-50125 Florence, FI, Italy; Univ Firenze, Dipartimento Fis & Astron, Via Sansone 1, I-50019 Sesto Fiorentino, FI, Italy; CNR, ISC, Via Madonna del Piano 10, I-50019 Sesto Fiorentino, Italy; Univ Firenze, LENS, Via Nello Carrara 1, I-50019 Sesto Fiorentino, FI, Italy.
Abstract: Quantum coherence, once mainly studied in atomic and optical systems, now offers potential for energy conversion technologies. It influences light absorption and emission, affecting energy conversion limits and efficiency. As a result, quantum coherence is being harnessed to boost performance in quantum heat engines, photocells, and photosynthetic-inspired platforms. Of particular interest in this context is the generation of Fano coherences, i.e., the formation of quantum coherences due to the interaction with the continuum of modes characterising an incoherent process. We aim to formalize mathematically the possibility of achieving steady-state Fano coherence in a V-type three-level quantum system using polarized incoherent radiation, without requiring the energy difference between the excited levels, & hstrok;Delta , to tend to zero. Specifically, in this scenario, it can be shown that the maximum steady-state Fano coherence is obtained through a non-trivial interplay between Delta , the average spontaneous decay rate gamma & strns; of the excited levels, and the intensity of the incoherent radiation, quantified by the mean photon number n & strns; . We perform this analysis by deriving the Bloch-Redfield equation from first-principles by quantizing the incoherent radiation. The resulting reduced dynamics of the system are analysed, so as to determine the lifetime of Fano coherence and identify the conditions under which it becomes stationary. We characterise distinct dynamical regimes, ranging from weak to strong pumping, in which steady-state Fano coherence emerges, and we quantitatively determine its magnitude. For each regime, we analyse the generation of Fano coherence as a function of both the intensity of the incoherent pumping and the energy splitting between the excited levels. We also assess how obtaining Fano coherence is modified by symmetric or asymmetric decay rates. These findings indicate that a three-level quantum system driven by polarized incoherent light can act as a robust resource for coherence-assisted energy conversion and storage. Finally, we discuss the experimental challenges associated with the implementation of the proposed model using an ensemble of Rubidium atoms. This work paves the way towards the forthcoming realization of experimental tests of Fano coherence generation in a relevant experimental setup by making use of a polarized incoherent radiation, in order to achieve quantum-enhanced energy storage and energy-conversion functionalities.
Journal/Review: SEMA JOURNAL
More Information: Open access funding provided by Universita degli Studi di Firenze within the CRUI-CARE Agreement.KeyWords: First-principle model; Quantized field; Fano coherences generation; Polarized incoherent light; Steady-state quantum coherence; Rubidium atoms; reduced dynamics; master equations; decoherence; entanglement; quantum correlationsDOI: 10.1007/s40324-026-00430-1
