No quantum effect in photosynthetic light harvesting

Time-dependent populations of local excited states, illustrated at four different times by illuminating the pigments accordingly. In addition, the exciton states are included as surroundings of pigments that appear and fade away according to the populations of these states in (B).

In a recent review article Donatas Zigmantas and colleagues from 16 universities and institutes in Europe, Canada, the US and Singapore critically assess previously proposed persistence and role of quantum coherence in photosynthetic light harvesting.

In the article they analyse the recent work on coherence in photosynthetic complexes, in particular, the results from femtosecond multidimensional spectroscopy studies on the Fenna-Matthews-Olson (FMO) protein, a light-harvesting complex from green sulfur bacteria, which has taken on an exemplary role in quantum biology.

Their results unambiguously show the absence of long-lived interexciton coherence on the time scales relevant for the energy transfer in this system, both at cryogenic and physiological temperatures. Thus it is recovered that nature instead of preserving coherence and avoiding dissipation, embraces the latter to facilitate the efficient and robust energy collection.

The full review article "Quantum biology revisited" in Sciences Advances.

A popular news article from the Lund University website (in Swedish).

One of the key papers that the review is based on was recently published in Nature.