Memory effects in the efficiency control of energy transfer under incoherent light excitation in noisy environments

Dutta, R and Bagchi, B (2024) Memory effects in the efficiency control of energy transfer under incoherent light excitation in noisy environments. In: Journal of Chemical Physics, 160 (24).

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Abstract

Fluctuations in energy gap and coupling constants between chromophores can play an important role in absorption and energy transfer across a collection of two-level systems. In photosynthesis, light-induced quantum coherence can affect the efficiency of energy transfer to the designated �trap� state. Theoretically, the interplay between fluctuations and coherence has been studied often, employing either a Markovian or a perturbative approximation. In this study, we depart from these approaches to incorporate memory effects by using Kubo�s quantum stochastic Liouville equation. We introduce the effects of decay of the created excitation (to the ground state) on the desired propagation and trapping that provides a direction of flow of the excitation. In the presence of light-induced pumping, we establish a relation between the efficiency, the mean survival time, and the correlation decay time of the bath-induced fluctuations. A decrease in the steady-state coherence during the transition from the non-Markovian regime to the Markovian limit results in a decrease in efficiency. As in the well-known Haken-Strobl model, the ratio of the square of fluctuation strength to the rate plays a critical role in determining the mechanism of energy transfer and in shaping the characteristics of the efficiency profile. We recover a connection between the transfer flux and the imaginary part of coherences in both equilibrium and excited bath states, in both correlated and uncorrelated bath models. We uncover a non-monotonic dependence of efficiency on site energy heterogeneity for both correlated and uncorrelated bath models. © 2024 Author(s).

Item Type:	Journal Article
Publication:	Journal of Chemical Physics
Publisher:	American Institute of Physics
Additional Information:	The copyright for this article belongs to American Institute of Physics.
Keywords:	Chromophores; Energy efficiency; Excited states; Ground state; Quantum theory; Stochastic systems, Control of energies; Coupling constants; Efficiency control; Energy-transfer; Incoherent light; Light excitation; Light-induced; Markovian; Memory effects; Noisy environment, Energy transfer, absorption; article; bath; chromatophore; controlled study; energy transfer; environmental noise; excitation; light; mean survival time; memory; nonhuman; photosynthesis; steady state
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	18 Dec 2024 08:45
Last Modified:	18 Dec 2024 08:45
URI:	http://eprints.iisc.ac.in/id/eprint/85853

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