Coherent control of an effective two-level system in a non-Markovian biomolecular environment

TL;DR

This paper explores how quantum coherence in a two-level biomolecular system is affected by a non-Markovian environment, revealing resonance phenomena and the impact of environmental memory on control strategies.

Contribution

It introduces a numerically exact method to analyze non-Markovian effects on driven quantum systems in biomolecular environments, extending understanding of coherence control.

Findings

Resonant behavior when reorganization energy matches driving frequency

Non-Markovian environment influences coherent destruction of tunneling

Quantum coherence depends on bath cut-off frequency and driving parameters

Abstract

We investigate the quantum coherent dynamics of an externally driven effective two-level system subjected to a slow Ohmic environment characteristic of biomolecular protein-solvent reservoirs in photosynthetic light harvesting complexes. By means of the numerically exact quasi adiabatic propagator path integral (QUAPI) method we are able to include non-Markovian features of the environment and show the dependence of the quantum coherence on the characteristic bath cut-off frequency omega_c as well as on the driving frequency omega_l and the field amplitude A. Our calculations extend from the weak coupling regime to the incoherent strong coupling regime. In the latter case, we find evidence for a resonant behaviour, beyond the expected behaviour, when the reorganization energy E_r coincides with the driving frequency. Moreover, we investigate how the coherent destruction of tunneling within the two-level system is influenced by the non-Markovian environment.