- You've probably heard about the recent observations of the star KIC 8462852. This star, over 1000 ly away, was observed by the Kepler planet-finding mission looking for transit signatures of extrasolar planets. Short version: It seems likely that some very weird objects are in orbit around the star, occasionally occulting large percentages (like more than 20%) of the star's light, far more light blocking and much less periodicity than is typically seen in the other 150,000 stars observed by Kepler. On the one hand, it was suggested that one exotic (though of course unlikely) explanation for this unique phenomenon is megastructures built by an alien civilization. This was freely admitted to be a long-shot, but generated a lot of attention and excitement. Now there has been a followup, where observers have pointed the Allen array at the star, and they have looked from 1-3 GHz for unusual radio emissions, finding nothing. This has generally been handled in the press like it kills the aliens explanation. Actually, if you read the paper, we'd only be able to detect such emissions (assuming they aren't beamed right at us) if the system was putting out something like a petawatt (1015 Watts) in that frequency range. The most likely explanation of the Kepler observations is still some natural phenomenon, but the lack of detectable radio signals is hardly conclusive evidence for that.
- I was previously unaware that the Institute for Quantum Information and Matter at CalTech had a really nice blog, called Quantum Frontiers. There, I learned from John Preskill that Matthew Fisher has been making serious suggestions that quantum information physics may be relevant to biological systems and neuroscience. It's important to look hard at these ideas, but I have to admit my own deep-rooted skepticism that either (1) entangled or superposition states survive in biological environments long enough to play a central role in neurological effects; or (2) that there are biological mechanisms for performing quantum information operations on such states. While nuclear spins are a comparatively isolated quantum system, it's very hard for me to see how they could be entangled and manipulated in some serious way biologically.
- You may need to sit down for this. We probably have not found evidence of parallel universes.
- Nature had a nice Halloween article about six "zombie" ideas in physics that are so-named because they either refuse to die or are "undead". I've talked about the Big G problem before.
A blog about condensed matter and nanoscale physics. Why should high energy and astro folks have all the fun?
Monday, November 09, 2015
Aliens, quantum consciousness, and the like
I've seen a number of interesting news items lately. Here are some that you may have missed.
I have always had mixed feelings about the claims of 'quantum effects' in biology. On the one hand, of course quantum mechanics plays a role in life, in the sense that if Planck's constant were zero, there would be no covalent bonding, London Dispersion Forces, or most any of the essential biochemistry necessary to keep life going. The claim that I understand these quantum biology folks to be making is that there are, in addition, 'non-trivial' quantum effects - but I have yet to be presented with a clear, intuitive statement of what that precisely means, and where we draw the line between trivial and non-trivial quantum effects. Doug, I was wondering if perhaps you could shed some light on this?
ReplyDeleteHi Tahir - Caveat: I'm no expert. I think there is a community out there that thinks there is actual quantum information processing that is going on in biological cognitive processes. People like Penrose have made very bold statements about this - see here. Fisher in his paper seems to be arguing that basic metabolism of adenosine triphosphate (ATP) produces pairs of phosphorus atoms with entangled nuclear spin states, and somehow these are relevant for cognition (?!). Other people have claimed that quantum coherence is relevant for the way olfaction works (see here). They argue that a second-order coherent quantum process, inelastic electron tunneling, is relevant to how we smell.
ReplyDeleteIn general, biology works in a very fluctuating, thermally driven, incoherent/overdamped environment. Quantum effects can surely be relevant for specific chemical reactions (e.g., photosystem I and photosynthesis). However, it's far from clear to me how you could ever have quantum information physics taking place in a biological environment, as this would require creation of superpositions and entangled states, coherent manipulation of those states, and some kind of readout.
Post by Ross McKenzie on the smelly issue
ReplyDeletehttp://condensedconcepts.blogspot.com/2015/07/quantum-biology-smells-bad.html
Wow, small world! I'm actually doing some DFT calculations for Matthew on the Posner molecule. I think solid arguments can be made for the existence of long-lived quantum states, though proposed mechanisms by which they could be active in cognition are still pretty sketchy. I'm mostly interested because something like the Posner molecule could be useful for quantum computation (a la http://www.nature.com/nature/journal/v414/n6866/full/414883a.html ) regardless any role in neuroscience.
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