From our other sites
The story
A new mathematical proof using quantum mechanics has been published explaining how migratory birds’ “magnetic compass” — the mechanism by which they sense Earth’s magnetic field to find their way — actually works. Building on the quantum biology hypothesis that pairs of electrons produced during biochemical reactions in the body, called “radical pairs,” become quantum entangled and shift their spin states under an external magnetic field (thereby changing reaction rates), the researchers mathematically demonstrated that the conditions for efficiently controlling quantum states (Pontryagin’s maximum principle) hold even under realistic magnetic fields. On the 5ch Science News+ board, discussion expanded beyond bird-navigation research to whether the theory could also apply to future quantum computers and to research on treating the brain with magnetic stimulation.
Why Does a Migratory Bird’s “Magnetic Compass” Work? New Math Theory Tackles a Quantum Biology Mystery
Quantum effects like superposition and entanglement, so crucial to building quantum computers, tend to be seen as physics phenomena with no direct link to living things.
In recent years, however, it has increasingly come to light that quantum effects are also at work in the life processes of living organisms.
Source: news.mynavi.jp / Original article here
What people said
>>Because this quantum state changes under an external magnetic field, the amount of product generated by the reaction could change too. In theory, then, birds may be sensing Earth's magnetic field by picking up on these shifts in chemical reactions happening inside their own bodies.
Since humans also generate their own bioelectricity, we carry an internal electromagnetic field too — so is the idea that the body distinguishes between that internal field and the radio waves, sound waves, or magnetism generated externally (like when you move your body)?
And taking that further, since there's a north pole and a south pole, does comparing the difference in magnetism across the globe let you work out direction?
Humans' "Sixth Sense": Ability to Sense Magnetism Discovered — University of Tokyo and Others
2019/3/19 10:54
https://www.google.com/goto?url=CAESewHrOzAVA3aCGW0rZzRdJJ6viGOto860NX8vGcZ_z93h42n0q7t–71DJ98udqG_-lEdCztxrpfN8hkgxc_opIYkhKbdRarfu3eP3dhDM9VVX715g2JIB__qDUAhcZQDCiGZXGXMvqq3J23_4CZRo0uYuBn_bSmPVogouw
>>Like migratory birds that can travel long distances without a map, humans too have the ability to sense Earth's magnetism, a joint research team from the University of Tokyo, Caltech, and others announced on the 19th in a U.S. academic journal. It's described as an unconscious, latent ability that could be called a "sixth sense," and some practical use for it may eventually be found.
>>The research team had previously succeeded in proving "Pontryagin's maximum principle" for spin systems in a magnetic field. That principle shows that to maximize the coherence of a quantum state, the optimal approach isn't to gradually ramp the magnetic field strength up and down, but to switch abruptly between extremely strong and weak states — a technique called "bang-bang control." The trouble is, generating electromagnetic fields that can flip that abruptly at quantum scales has been a major technical hurdle.
>>This mathematical framework could become the foundation for lab experiments that control quantum systems at near-optimal levels — useful not only for unraveling how birds navigate, but potentially for future quantum computers too. The team says this work worked out the mathematical principles to guide such experiments, extending a general math principle into the quantum-systems domain — meaning experimentalists can now be given concrete guidance on exactly how to apply the magnetic fields needed to test this control method.
Tokyo-Yokohama TMS Clinic
https://www.google.com/goto?url=CAESdQHrOzAVIp7grrHPkZVxOVMwZj9fZ90AFAo9UhNWxJ8MjZCwj4s3YP2rDxwCAb9BtFt93aA9_M-bYeDBVf8hDsln76ni277rHt8uw65D8BolXXfmadHKqgAjS4rGI8EukO3FPtKb_fRH0k67gDc-BnVDIa_pvQ
>>rTMS (repetitive Transcranial Magnetic Stimulation) is what it's called in English; in Japanese it's "repetitive transcranial magnetic stimulation therapy."
>>TMS therapy uses magnetism to induce weak electrical currents in the brain, which act on neural activity.
>>In Japan, insurance coverage began in 2019 for adult depression patients who don't respond well enough to existing antidepressant treatment, though extra requirements apply around patients, facilities, equipment, and method. Treatment at our clinic is out-of-pocket and includes uses that fall outside the scope of domestically approved indications and methods.
Chinese Startup Enters Non-Invasive BCI Space, Betting on Ultrasound Tech
2026.02.03
https://wired.jp/article/this-chinese-startup-wants-to-build-a-new-brain-computer-interface-no-implant-required-gestalta/
>>The company is aiming to develop a device that delivers focused ultrasound to the brain to treat chronic pain. Preliminary research showed that stimulating the anterior cingulate cortex — the brain region involved in the emotional side of pain — can dial down pain for up to a week.
>>The first-generation device is a stationary, desktop unit, so patients have to visit a medical facility for treatment.
>>The second-generation device is planned as a helmet-style wearable patients could use at home under a doctor's guidance.
Research on Improving the Accuracy of Ultrasound Communication Using the Body as a Transmission Medium
https://www.oyama-ct.ac.jp/tosyo/kiyou/47/12.pdf
2024/03/04
https://www.chubu.ac.jp/news/31965/
>>Transcranial static magnetic field stimulation (tSMS, see photo at right) is a non-invasive brain-stimulation method under active research that uses magnets to safely and easily alter brain function. tSMS has already been shown to improve upper-limb movement in stroke rehabilitation, raising hopes it could be applied to rehab for stroke and intractable neurological diseases. Until now, though, exactly how tSMS magnets act on the brain had never been clarified.
after billions of years of "R&D," there's rationality baked into biology that human science still hasn't even scratched the surface of.
biology is packed with organisms that already put it into practice after billions of years of trial and error.
Background and Key Points of This Discussion
Quantum biology is a field that proposes quantum-mechanical effects play a role in biochemical reactions inside living things — photosynthesis being one example — and birds’ magnetic sensing has long been studied as a flagship case. What’s new here is that this theory mathematically backs up, within the framework of “Pontryagin’s maximum principle” (a control theory for optimally manipulating quantum states), how the quantum-entangled state of electrons (radical pairs) shifts under a magnetic field, and it lays out the conditions under which realistic magnetic-field control can reproduce coherence above 99% of the theoretical optimum. The thread ran with speculation about whether this framework could extend to future quantum computer development and to brain-treatment research via magnetic stimulation — though it’s worth flagging that the biological mechanism of birds’ magnetic sensing itself still hasn’t been fully proven experimentally; this result is, at best, a mathematical foundation that supports future verification experiments. A few posts in the thread also veered into conspiracy-theory territory about schizophrenia and “thought reading,” but those were unrelated to the main topic and have been left out of this article.
*This article was compiled by excerpting and summarizing the 5ch (Science News+) thread “Why Does a Migratory Bird’s ‘Magnetic Compass’ Work? New Math Theory Tackles a Quantum Biology Mystery.”
Leave a Reply