One of the proposals of quantum biology is a quantum mechanism for the mysterious looking ability of birds and fishes to find back to the place, where they were born. It is believed that navigation involves detection of the inclination of the local magnetic field of Earth but not its direction as in the ordinary ordinary compass. The alternative option states that birds have an analog of compass in their brain. The challenge is to understand what is the mechanism making possible to get the information about magnetic field and how this information is transformed to a chemical signal and eventually to a pattern of nerve pulses. In TGD framework one can challenge the assumption that the magnetic field of Earth is what makes possible the navigation and even what the navigation means.
Quantum biologists try to solve the problem using standard quantum physics. The formidable looking problem is that the energy scale for magnetic energies is extremely small. In the magnetic field of Earth the magnetic interaction cyclotron energy for electron is by factor of order one million below the thermal energy. If one believes of quantum physics in its standard form, one should understand how it is possible to generate a signal making possible non-trivial chemical effects. The proposal that has gained widest acceptance is known has as radical-pair mechanism (RPM) and has raised hopes about circumvent this problem.
The answer to the question whether RPM works is very important from the point of view of TGD based explanation for macroscopic quantum effects in living matter since TGD based model involves new quantum physics via the hypothesis that dark matter corresponds to heff=n× h0 phases located at flux tubes of "magnetic body" (MB). If RPM fails, TGD based quantum biology would be the next natural trial (if science proceeded by trying first all options that fail).
I have already earlier proposed a TGD based model for various difficult-to-understand findings related to magneto-reception and pace-maker of circadian rhythym. The model discussed also photo-taxis and gravi-taxis. The improved model discussed here relies on essentially the same elements but does not assume RPM as the mechanism producing nuclear spin polarization as an analog of compass.
Improved TGD inpired model
Magnetic flux tubes are key objects of TGD based quantum biology able to act as sending and receiving antennas and if they contain cyclotron Bose-Einstein condensates they can act also as quantum compasses communicating the orientation of the external magnetic field by emission of Larmor radiation at cyclotron frequencies fc. This radiation is received by other flux tubes at resonance and the modulation of fc produces resonances as ticks of the clock. The energies involved must be above thermal energy and heff=hgr hypothesis guarantees this.
Pace-maker function requires cell membrane as a generalized Josephson junction (GJJ) emitting generalized Josephson radiation with energy EG,J, which is sum of Josephson energy EJ=ZeV and difference Δ Ec(hbargr) of cyclotron energies at the two sides of membrane. The TGD view about metabolic energy as manner to increase heff=hgr allows to interpret irradiation by blue light as metabolic energy feed, and explains the slowing down of the circadian period as a reduction of ordinary Josephson frequency fJ= ZeV/hbargr. Also the loss of rhythm can be understood as a transition in which the analog of generalized Josephson junction as a gravitational pendulum makes a transition from rotational to vibrational motion. Photo-receptors such as cytochrome appear as absorbers of dark photons transformed to bio-photons and transform dark photon information to chemical information.
See the article TGD inspired model for magneto-reception and circadian rhythm or the chapter Can quantum biology really do without new physics? .
For a summary of earlier postings see Latest progress in TGD.