Examining the quantum signatures of optimal excitation energy transfer

TL;DR

This paper investigates how quantum coherence, entanglement, and dissipation influence energy transfer in light-harvesting systems, revealing that optimal transfer occurs with minimal quantum coherence, driven by fundamental symmetry breaking.

Contribution

It demonstrates that energy transfer efficiency is maximized when quantum coherence and entanglement are minimized, linking this to symmetry breaking and vibrational effects in quantum systems.

Findings

Optimal energy transfer occurs with minimal quantum coherence and entanglement.

Spontaneous parity time-reversal symmetry breaking underpins the transfer dynamics.

Vibrational fluctuations can enhance transport via dephasing-assisted mechanisms.

Abstract

Light-harvesting via the transport and trapping of optically-induced electronic excitations is of fundamental interest to the design of new energy efficient quantum technologies. Using a paradigmatic quantum optical model, we study the influence of coherence, entanglement, and cooperative dissipation on the transport and capture of excitation energy. In particular, we demonstrate that the rate of energy extraction is optimized under conditions that minimize the quantum coherence and entanglement of the system. We show that this finding is not limited to disordered or high temperature systems but is instead a fundamental consequence of spontaneous parity time-reversal symmetry breaking associated with the quantum-to-classical transition. We then examine the effects of vibrational fluctuations, revealing a strong dephasing assisted transport enhancement for delocalized excitations in the presence of cooperative interactions. Our results highlight the rich, emergent behavior associated with decoherence and may be relevant to the study of biological photosynthetic antenna complexes or to the design of room-temperature quantum devices.