arXiv:2512.17741 · Philosophical Transactions of the Royal Society A Mathematical Physical and Engineering Sciences

Signatures of coherent energy transfer and exciton delocalization in time-resolved optical cross correlations

Hallmann Óskar Gestsson, Alexandra Olaya-Castro

physics.chem-phphysics.bio-phquant-phSubmitted Dec 19, 2025• Announced Dec 22, 2025• 1 citation

Abstract

We investigate how optical second-order cross correlations witness the quantum features of a prototype donor-acceptor light-harvesting unit. By considering a pair of detuned two-level emitters electronically coupled and incoherently driven to a non-equilibrium steady-state, we gain insight into how electronic quantum properties such as exciton eigenstate delocalization, coherent energy transfer and steady-state electronic coherence, are manifested in the joint probability of emission or optical second-order cross correlation. Specifically, we show that the frequency associated with oscillations present in time-resolved second-order cross correlation functions quantifies not only the time scale of coherent energy transfer but also the degree of delocalization of the exciton eigenstates. Furthermore, we show that time-resolved cross correlations directly witness steady-state electronic coherence. Our work strengthens the idea that measurements of the intensity quantum cross correlations can provide distinctive signatures of the quantum behavior of biophysical emitters.

Journal reference: Phil. Trans. R. Soc. A (2026) 384: 20220269
DOI: 10.1098/rsta.2022.0269
Comments: 10 pages, 7 figures

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