Using non-Markovian measures to evaluate quantum master equations for photosynthesis

Area of Science:

• Quantum Physics
• Biophysics
• Computational Chemistry

Background:

• Open quantum systems require approximations for modeling dynamics.
• Evaluating the accuracy of these approximations is essential for understanding complex systems like photosynthetic light-harvesting complexes.

Purpose of the Study:

• To propose and utilize entanglement and non-Markovianity as benchmarks for assessing approximate methods in open quantum systems.
• To compare the performance of two common perturbative approximations against numerically exact results.

Main Methods:

• Application of two perturbative, non-Markovian approximations to a photosynthetic dimer model.
• Comparison with results from the numerically exact Hierarchy Equation of Motion (HEOM).
• Analysis of entanglement and non-Markovianity measures to quantify deviations.

Main Results:

• Entanglement and non-Markovianity measures reveal how approximations overestimate or underestimate memory effects and quantum coherence.
• Both approximate and exact results indicate that non-Markovianity can counter-intuitively increase with temperature and environmental coupling.

Conclusions:

• Entanglement and non-Markovianity serve as effective benchmarks for evaluating approximations in open quantum system dynamics.
• The study highlights the complex interplay between system-environment coupling, temperature, and memory effects in quantum systems.