- 3707 - QUANTUM MECHANICS - how birds navigate? Quantum Mechanics is a part of science that is faced with strange choices in thinking about the nature of reality and our place in it. Reality really is "spooky" . But what is that spookiness telling us? No one really knows. Every interpretation of quantum mechanics is forced to accept something about reality that seems really weird. Even how birds navigate.
--------------- 3707 - QUANTUM MECHANICS - how birds navigate?
- On October 11, the 2022 Nobel Prize in Physics was awarded to scientists’ who’s work opened up new frontiers in quantum weirdness. What their findings showed is that the most philosophically challenging aspects of quantum mechanics are also its most essential. Those challenges mean that anyone taking quantum mechanics seriously is faced with strange choices in thinking about the nature of reality and our place in it.
-
- When particles are in quantum entanglement, they can no longer be thought of as having separate properties. Two particles have properties that we cannot know before we take measurements of them. If the particles are entangled, then a measurement of just one out of the pair instantly establishes what a measurement on the other would produce.
-
- This is true even if the particles are separated by a distance so large that there would be no chance for them to communicate in the time it would take to measure one and then the other. In this way, entangled particles seem to form a coherent whole across space and time faster than the speed of light.
-
- Entanglement is exactly the kind of “spooky action at a distance” that Einstein was famously concerned about in quantum mechanics. It’s why he felt quantum theory was somehow incomplete, meaning there must be something about it we have yet to understand.
-
- What Einstein wanted was a physics that returned us to a classical view of reality, a view where things have their own distinct properties, regardless of whether a measurement of those properties was made or not.
-
- In 1964 Irish physicist John Stewart Bell proposed a way to clearly differentiate Einstein’s vision of reality from the spookier quantum version. Measuring entanglement was the key. It took a few decades, but eventually measurements of separate entangled particles became commonplace, and in every experiment, Einstein lost. Reality really is spooky operating faster than the speed of light.
-
- Unlike classical physics, quantum mechanics always requires an interpretation to be pinned on top of mathematical formalism. Whereas Newtonian physicists could easily imagine their laws of motion governing atoms that acted just like tiny billiard balls, quantum physicists never had any such assurance.
-
- The heart of the dilemma comes with the role of measurement. Quantum mechanics is famous for its wave-particle duality, where an electron, for example, will behave as a wave or a particle depending on which kind of experiment you perform. It’s the choice of measurement of a wave kind or a particle kind that seems to determine the result.
-
- Is the electron a wave spread out through space, or is it a particle holding just a single position at any one time? And why should the choice made by a measurer have any effect? What is a measurement anyway, and what is a measurer? Is it always a person, an observer, or does any interaction with any kind of “thing” count? The answers to these questions cannot be found in the mathematical theory. at least not yet.
-
- The “Many Worlds Interpretation” of quantum mechanics holds that there is still a reality out there independent of measurers, but there is a price paid for this view. Every measurement, every interaction with anything, forces the Universe to split into a near infinity of copies. Each of these many worlds holds one of the possible measurement results.
-
- In “Quantum Bayesianism“, the measurements of quantum mechanics never reveal the world in itself, but our interactions with the world. “QBism” has no problem explaining the importance of measurements, but it gives up on the dream of a perfectly objective view of reality.
-
- The Many Worlds interpretation is very different from Quantum Bayesianism. But each shows the kinds of choices you must make when you try to ask what quantum mechanics tells us about reality.
-
- Science have not figured this out but birds have. Birds' navigation using Earth's very faint magnetic fields suggests an incredible level of sensitivity. There's reason to think that sensitivity may be based on “quantum entanglement” in “crypto chrome” in their eyes.
-
- This question how birds navigate has puzzled biologists ever since the manner in which birds navigate became apparent. How can birds possibly be able to perceive and follow something as faint as the Earth’s magnetic field? It may be that they perceive it through the interaction of entangled quantum particles in their eyes.
-
- Behind this hypothesis is years of confirming and seeking to explain birds’ phenomenal sensitivity to Earth’s magnetic field. The most plausible explanation for it has to do with the effect of the magnetic field on entangled molecules of a chemical in birds’ eyes, Cry4, or cryptochrome.
-
- Other animals, and plants, share the chemical, though it’s believed that birds have developed their own variant. When a photon, a light particle, hits a cryptochrome molecule in a bird’s eye, it knocks loose an electron that may then become associated with a second molecule. The two molecules then both have an odd number of electrons, and they become a radical pair.
-
- Since the oddness of both of these radicals was created simultaneously by that loosened electron, the spins of one electron in each molecule of cryptochrome become locked together in relation to each other and the radical pair becomes entangled.
-
- This entangled state is extremely fragile, and temporary, so it won’t survive beyond just 100 microseconds. But during that brief interim, the radical pair will be in either one of two states. The suspicion is that the Earth’s magnetic field affects the amount of time the molecules spend in either state, and changes to the duration of these states somehow tells the bird where he or she is.
-
- The exact means by which the bird perceives them is unknown, though it’s been suggested that it may have to do with one or both states causing the presence of absence of some as-yet-unidentifed chemical.
-
- This might not seem to make sense because magnetic fields are so weak, but it’s real. How weak? “The energy of interaction of a molecule with a 50-μT magnetic field is >6 orders of magnitude smaller than the average thermal energy kBT, which in turn is 10–100 times smaller than the strength of a chemical bond.
-
- The radical pair mechanism has been known since the 1970s that certain chemical reactions do in fact respond to applied magnetic fields. The study also notes that radicals always seem to be involved.
-
- The “radical pair theory” is really the best explanation for birds’ navigation systems we have, since experiments attempting to detect effects of magnetic fields directly on biological processes, bypassing chemistry, have come up empty-handed.
-
- Perhaps photons are throwing electrons far enough from their normal thermal equilibrium that they remain entangled long enough to respond to the subtle cues coming from the planet’s magnetic field. Quantum entangled particles created by scientists last for mere nanoseconds.
-
- It seems nature has found a way to make these quantum states live much longer than we’d expect, and much longer than we can do in the lab. No one thought that was possible.
-
- The most compelling evidence of birds’ amazing sensitivity comes from experiments with caged European robins, whose navigation abilities were easily disrupted. Linearly polarized radio frequency fields 100 times weaker than the Earth’s field (500 nanoT), with frequencies of 7.0 MHz or 1.315 MHz, are sufficient to disrupt the migratory orientation of caged European robins.
-
- Playing with the magnetic field also easily baffled the birds, with researchers finding a 20–30% increase or decrease in the intensity of the ambient magnetic field is sufficient to disorient caged birds.
-
- Clearly, avians possess an almost unbelievably delicate sensing mechanism of some sort. The intersection of quantum mechanics and biology, even human biology, is a fascinating notion.
-
- Some wonder if it may also relate to consciousness and other currently bewildering phenomena. If we can come to fully understand the mechanics or chemistry of birds’ impressive capabilities, what other mysteries might we be able to unlock?
-
October 13, 2022 QUANTUM MECHANICS - how birds navigate? 3707
----------------------------------------------------------------------------------------
----- Comments appreciated and Pass it on to whomever is interested. ---
--- Some reviews are at: -------------- http://jdetrick.blogspot.com -----
-- email feedback, corrections, request for copies or Index of all reviews
--- to: ------ jamesdetrick@comcast.net ------ “Jim Detrick” -----------
--------------------- --- Sunday, October 16, 2022 ---------------------------
No comments:
Post a Comment