The Hyperfine Coupling Radical Pair Mechanism of Biological Effects on Weak Magnetic Fields

More recent concerns have been raised about the biological effects of all different weak magnetic fields (MFs) with the development of electric device era and information era. The biological effects due to weak MFs just like a hypomagnetic field (HMF) or near-null magnetic field is a very important subject for aerospace traveling and space station living. A large number of studies on the biological effects of other weak MFs have been carried out. The biological effects of different weak MFs can be negative or positive. Many mechanisms to explain the bioeffects of weak MFs have been given. Are there possible common mechanisms of the different biological effects in different weak MFs ? It’s unbelievable and sound impossible at first sight that different bioeffects of different weak MFs have common mechanisms. But possible common mechanisms can exist. In this study, the author proposes the relations between the singlet yield of the radical pair and the weak MFs are the possible common mechanisms. Giving one possible common mechanism of bioeffects of all different weak MFs including impulsed ones is the first to the author’s known. Here, the weak MFs are ones that cannot produce thermal bioeffects not only limited below 1mT

The radical pair mechanism of biological effects on hypomagnetic fields and one method to verify it

The biological effects due to a hypomagnetic field (HMF) is a very important subject not only for aerospace traveling and space station living but also for some magnetic shielding conditions on the ground just like the underground bunkers and etc. However, to my knowledge, the mechanisms which can be related to the biological effects of a HMF remain unclear. In this study, I firstly summary one radical pair mechanism of biological effects on a HMF based on present researches, and then propose how to prove the radical pair mechanism’s truth in biological effects on a HMF through experiments. In the way of how to prove the radical pair mechanism’s truth I give the relation between the singlet yield of the radical pair and the angle describing the orientation of a HMF to the basis of the hyperfine tensor related to the electron spin and the nuclei spin is the possible one radical pair mechanism on one hand, and give the crucial method which is through that angle changed causes the biological effects in vivo or vitro to prove or disprove the mechanism on the other hand, because the biological effects of a HMF can be related with that angle, which is very easy to be controlled in experiments

Backaction of a charge detector on a double quantum dot

We develop a master equation approach to study the backaction of quantum point contact (QPC) on a double quantum dot (DQD) at zero bias voltage. We reveal why electrons can pass through the zero-bias DQD only when the bias voltage across the QPC exceeds a threshold value determined by the eigenstate energy difference of the DQD. This derived excitation condition agrees well with experiments on QPC-induced inelastic electron tunneling through a DQD [S. Gustavsson et al., Phys. Rev. Lett. 99, 206804(2007)]. Moreover, we propose a new scheme to generate a pure spin current by the QPC in the absence of a charge current.Comment: 6 pages, 4 figure

Cooling a nanomechanical resonator by a triple quantum dot

We propose an approach for achieving ground-state cooling of a nanomechanical resonator (NAMR) capacitively coupled to a triple quantum dot (TQD). This TQD is an electronic analog of a three-level atom in $\Lambda$ configuration which allows an electron to enter it via lower-energy states and to exit only from a higher-energy state. By tuning the degeneracy of the two lower-energy states in the TQD, an electron can be trapped in a dark state caused by destructive quantum interference between the two tunneling pathways to the higher-energy state. Therefore, ground-state cooling of an NAMR can be achieved when electrons absorb readily and repeatedly energy quanta from the NAMR for excitations.Comment: 6 pages, 3 figure

Biological Effects Due to Hypomagnetic Field and Its Research Progress

The biological effects due to hypomagnetic field (HMF) is a very important subject for aerospace travelling and space station living, and a large number of studies on the bioeffects of the HMF have been carried out; however, many essential problems, such as physical mechanism, the harmful for human beings and other living organism of the biological effects, are still remaining unknown. In order to promote the solution to these problems, we assembled, classified and analyzed the studies on the biological effects due to the HMF. About one of the essential problem, i.e. the physical mechanism of the biological effects of HMF, we think that the yield of the singlet spin state of the radical pair theor