Do living systems already harness quantum mechanics in a "non-trivial" way?
How do we define "non-trivial"? A good criteria is whether biologists and chemists need quantum physicists to understand the phenomena of interest?
Specifically, they did a detailed analysis of decoherence and entanglement in the radical pair model for magnetoreception (where the small magnetic field of the earth causes a different decay rate for singlet and triplet channels). One thing I learnt is that a key to making this model work is that the different spins experience a different spin anisotropy associated with the hyperfine interaction. (How can we justify this asymmetry?)
Recent experiments showed that a very weak oscillatory magnetic field resonant with the electron Larmor frequency will stop the compass working.
unknown rate = 10^4 per sec to disrupt compass
The Oxford group estimated the decoherence time must be shorter than 100 microsec.
This may seem long since N @ C60 has a decoherence time of 80 microsec.
An open question is the biomolecular justification for the radical pair model and whether the spins need to be in a protected environment.
A candidate molecule cryptochrome have too many nuclear spins.
This is fascinating. Is it "non-trivial"? Well it is worth noting that
1. all the theoretical machinery used was more than 50 years old [i.e. preceded quantum information theory].
2. the entanglement involved involves two electrons and just two molecules and so is not "macroscopic"
A question was ask about whether the bird had evolved to develop this feature because it has a survival advantage. It is important to remember that not every function of an animal has been optimised by evolution, as discussed here.
A question was ask about whether the bird had evolved to develop this feature because it has a survival advantage. It is important to remember that not every function of an animal has been optimised by evolution, as discussed here.
No comments:
Post a Comment