The 2007 discovery of long-lived quantum coherence in the FMO complex sparked a decade of quantum biology research. A fundamental tension remains unresolved: whether vibronic coupling genuinely routes excitons toward reaction centers more efficiently than classical Förster transfer, or whether observed coherence signals are spectroscopic artifacts amplified by ultrafast laser pulses.

Two-dimensional electronic spectroscopy studies disagree sharply on coherence lifetimes at physiological temperatures — ranging from ~60 fs to >300 fs — with several groups reporting near-complete decoherence under conditions that don't reflect in vivo cellular environments. If coherence is purely incidental, decades of quantum-biology-inspired solar cell design rest on a false premise.

What experimental setup would definitively distinguish functional quantum coherence from thermally-dressed classical hopping in a living photosynthetic system?