Optimized excitonic transport mediated by local energy defects: survival of optimization laws in the presence of dephasing

TL;DR

This study investigates how environmental dephasing impacts optimized excitonic energy transport in star and chain networks, revealing that optimization laws persist under weak dephasing but are lost with stronger dephasing due to the quantum Zeno effect.

Contribution

It extends previous work by analyzing the robustness of excitonic transport optimization laws under dephasing in star and chain networks.

Findings

Optimization of energy transport persists under weak dephasing.

Both networks show similar behavior regarding the survival of optimization laws.

Strong dephasing destroys optimization due to the quantum Zeno effect.

Abstract

In an extended star with peripheral defects and a core occupied by a trap, it has been shown that exciton-mediated energy transport from the periphery to the core can be optimized [S. Yalouz et al. Phys. Rev. E 106, 064313 (2022)]. If the defects are judiciously chosen, the exciton dynamics is isomorphic to that of an asymmetric chain and a speedup of the excitonic propagation is observed. Here, we extend this previous work by considering that the exciton in both an extended star and an asymmetric chain, is perturbed by the presence of a dephasing environment. Simulating the dynamics using a Lindblad master equation, two questions are addressed: how does the environment affect the energy transport on these two networks? And, do the two systems still behave equivalently in the presence of dephasing? Our results reveal that the time-scale for the exciton dynamics strongly depends on the nature of the network. But quite surprisingly, the two networks behave similarly regarding the survival of their optimization law. In both cases, the energy transport can be improved using the same original optimal tuning of energy defects as long as the dephasing remains weak. However, for moderate/strong dephasing, the optimization law is lost due to quantum Zeno effect.