Full microscopic simulations uncover persistent quantum effects in primary photosynthesis

Area of Science:

• Quantum biology
• Photosynthesis
• Spectroscopy

Background:

• The role of quantum effects in photosynthetic excitation energy transfer remains a subject of intense debate.
• Distinguishing quantum coherence from vibrational motion using nonlinear spectroscopy is challenging.
• Previous numerical simulations were often approximate, limiting the study of realistic models.

Purpose of the Study:

• To investigate the presence and persistence of quantum effects in photosynthetic energy transfer.
• To accurately simulate the Fenna-Matthews-Olson (FMO) complex using nonperturbative methods.
• To clarify the interpretation of experimental data regarding quantum phenomena in photosynthesis.

Main Methods:

• Nonperturbative, accurate microscopic model simulations of the FMO complex.
• Simulations performed at cryogenic and room temperatures.
• Analysis of excitonic coherences and their timescales.

Main Results:

• Demonstrated the presence of long-lived excitonic coherences in the FMO complex.
• These coherences persist on picosecond timescales, comparable to energy transfer times.
• Showed that approximate theoretical methods can misinterpret experimental data.

Conclusions:

• Long-lived quantum effects, specifically excitonic coherences, are present in photosynthetic energy transfer.
• Accurate, full microscopic simulations are crucial for identifying quantum phenomena in experiments.
• Overreliance on approximate methods may lead to overlooking significant quantum contributions.