We’ve always been fascinated by evidence showing that there seem to be quantum mechanical interactions happening within biological systems. It is believed that birds have molecules in their heads that interact with photons and the Earth’s magnetic field. When one such molecule captures a photon, it releases a pair of electrons that are entangled to each other. Now researchers from Oxford University have calculated that the entanglement between the pair of electrons must last longer than any previously observed entanglement events.
From the Physics arXiv Blog over at MIT Technology Teview:
In the absence of a magnetic field, this pair would recombine to form the original molecular state. But the earth’s magnetic field can flip the spin of one of these electrons, allowing them to recombine in a different way and leaving the molecule in an alternative chemical state that the bird can sense. The result is that the bird “sees” the earth’s magnetic field as it flies.
This raises an interesting question: how long does this entangled state last?
Vedral and co have done the numbers and say that it lasts for at least 100 microseconds. That’s an extraordinary figure. The best that humans have measured is 80 microseconds for so-called electron spin relaxation in C60 buckyballs.
Curiously, entanglement is not being put to work in magnetoreception; it is simply a by-product of the process.
More at Physics arXiv Blog…
Article at arXiv.org: Quantum coherence and entanglement in the avian compass