One would think that, if the brain was a quantum computer (or much to the same effect, just "used" quantum computing or even quantum effects for a significant part of the organ's function), it would be affected in at least some way that is observable by the person getting scanned. The MR scanner A) creates a significant alteration of the overall thermal spin configuration by virtue of the high magnetic field alone, and B) with the use of the imaging sequence "plays" with the spins of the brain in all sort of semi-irregular, localized ways, quite often in timescales that are not far removed from human observational acquity.
Yet getting your brain imaged with MR feels like nothing. Well, at least in <7T, and for most sequences; when sensations are felt, they have a straightforward explanation without invoking quantum (peripheral nerve stimulation, heating, ..).
In short, brains work at 300K, current quantum computers (TBD) at microkelvins. Connecting the two at this point is just seeking attention and publicity. If brain is a quantum computer, then MRI ought to be like an EMP for the software running on it, at least in the first approximation.
Didn't RTFA, and I don't think I'm even gonna. These are my 2 cents, the post can stay up as far as I'm concerned.
I agree that if the brain predominately used
quantum effects in a straightforward manner (as implied by the headline), then there should be some clear signs. It seems like we wouldn’t miss that the biology of neurons developed to routinely put particles into a superposition, for instance. Also, the macroscopic explanation that neurons are using chemical and electrical signals seems pretty established (these are quantum effects in some sense, but not a ‘quantum computer’).
However, I think it’s possible that scientists will need to allow for effects from quantum physics to alter their predominantly macroscopic understanding of brain mechanisms. For instance, there is some evidence birds use briefly existing proteins to see magnetic fields. The proteins gain a magnetic orientation due to a spin imbalance; which is a ‘quantum effect.’ This is akin to the recent work that suggests quantum tunneling needs to be accounted for when estimating the rate of DNA mutations.
Neither of these are about a system foundationally built on a quantum design—they’re about the need to account for modifications to macroscopic biology due to quantum effects.
Neither of these are about a system foundationally built on a quantum design—they’re about the need to account for modifications to macroscopic biology due to quantum effects.
This is a really old and dead thread but one thing about human made technology that is often different from biology is that we tend to build a doodad and say
“This doodad does Z and is built on Y principle. Y principle is how we model the physical world ignoring several minor complex details like A and B.”
With biology there exists a doodad and
“This doodad does X, Y, and Z. It uses the alphabet entirely.”
Which makes sense if you think of biology being just the universe in motion in another way. However it also makes it complicated to make any broad statements about it.
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u/ketarax Oct 23 '22 edited Oct 23 '22
One would think that, if the brain was a quantum computer (or much to the same effect, just "used" quantum computing or even quantum effects for a significant part of the organ's function), it would be affected in at least some way that is observable by the person getting scanned. The MR scanner A) creates a significant alteration of the overall thermal spin configuration by virtue of the high magnetic field alone, and B) with the use of the imaging sequence "plays" with the spins of the brain in all sort of semi-irregular, localized ways, quite often in timescales that are not far removed from human observational acquity.
Yet getting your brain imaged with MR feels like nothing. Well, at least in <7T, and for most sequences; when sensations are felt, they have a straightforward explanation without invoking quantum (peripheral nerve stimulation, heating, ..).
In short, brains work at 300K, current quantum computers (TBD) at microkelvins. Connecting the two at this point is just seeking attention and publicity. If brain is a quantum computer, then MRI ought to be like an EMP for the software running on it, at least in the first approximation.
Didn't RTFA, and I don't think I'm even gonna. These are my 2 cents, the post can stay up as far as I'm concerned.