Why do plants transport energy so efficiently and quickly?

Quantum mechanics helps with photosynthesis

This process, which cannot be understood satisfactorily by classical physics alone, occurs constantly in green plants and other photosynthetic organisms, such as photosynthetic bacteria. However, the exact mechanisms have still not been fully elucidated. Hauer and first author Erika Keil see their study as an important new basis in the effort to clarify how chlorophyll, the pigment in leaf green, works. Applying these findings in the design of artificial photosynthesis units could help to utilize solar energy with unprecedented efficiency for electricity generation or photochemistry.

For the study, the researchers examined two specific sections of the spectrum in which chlorophyll absorbs light: the low-energy Q region (yellow to red spectral range) and the high-energy B region (blue to green). The Q region consists of two different electronic states that are quantum mechanically coupled. This coupling leads to loss-free energy transport in the molecule. The system then relaxes through “cooling”, i.e. by releasing energy in the form of heat. The study shows that quantum mechanical effects can have a decisive influence on biologically relevant processes.