Entanglement, tunnelling and coherence – known from the tightly organised lab set-ups of quantum mechanics – may also do their work in the warm, messy environment of the biological cell.

Migratory birds such as pigeons and robins use the earth’s magnetic field to orient themselves when travelling. Chemical research suggests that they can perceive this weak magnetic field with the help of a quantum chemical phenomenon in their retinas. This is surprising, because chemical reactions are normally quite insensitive to magnetic fields. ‘But it seems that molecules in the retina of birds are very sensitive to magnetic fields’, says physical chemist Peter Hore of Oxford University. He has been studying this chemical magnetoreception for two decades.

It is one of the examples of the field of quantum biochemistry: the role of quantum mechanical effects such as entanglement, tunnelling and coherence in biochemistry. Quantum mechanical effects might, for example, dramatically improve the efficiency of certain enzymes, play a role in molecule detection in olfactory sensors in the nose, and in the hydrogen bonding between base pairs in DNA. Even the miraculously accelerated computing power promised by quantum computers might have been discovered by nature millions of years earlier to increase the efficiency of photosynthesis. Might, because whether quantum mechanical effects actually play a crucial role has not yet been definitively proven anywhere. ‘I myself am not convinced that we have the definitive mechanism’, says Hore about the magnetoreception. ‘Although I think there is more evidence for it than for any other mechanism. But others think it’s all a load of rubbish.’