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Sense of Smell Tied To Quantum Physics?
SpaceAdmiral writes "A controversial theory that proposes that our sense of smell is based not on the shape of the molecules that enter our nose but on their vibrations was given a boost recently when University College London researchers determined that the quantum physics involved makes sense. The theory, proposed in the mid-1990s by biophysicist Luca Turin, suggests that electron tunneling initiates the smell signal being sent to the brain. It could explain why similarly shaped molecules can have very different smells, and molecules with very different structures can smell similar." Turin has now formed a company to design odorants using his theory, and claims an advantage over the competition of two orders of magnitude in rate of discovery. The article concludes, "At the very least, he is putting his money where his nose is."
I remember reading about this guy (probably on the Slashdots) years ago, and I hoped that this would be one of those rare cases of someone who is rejected by the "scientific community" and then goes on to success. There are so many scientists out there that end up on dead-end roads (I'm looking at you, Cold Fusion), that it's nice to have a reminder that there's still reason to explore.
For proof that success is the best revenge, just check out the company's product list. They're making a killing by creating replacements for aromatic allergens.
I guess one thing that made me think he was on to something was his reaction to the scientific community's snub -- one response I recall likened a quantum-mechanical sense of smell to "food being processed in the stomach by nuclear reactions". He did NOT go around telling the world that the scientist cabal was out to get him, or that the perfume cartel was conspiring to suppress his work. He simply went about building a successful business by *using* his hypothesis to create and license useful, concrete products.
You know, I think this is why we have patents in the first place. Not so megacorporations can trademark "business practices" -- if I hear another insurance company or bank describe their latest gimmick with a "patent pending" disclaimer I'm gonna puke. It's so some little guy on the right track can take a risk and come out on top.
Stressed? Me? Of course not. Stress is what a rubber band feels before it breaks, silly.
I have this feeling we're just on the edge of a scientific revolution in understanding the human body. How many stories in the last few years have we read about using various types of stem cells that give birth to new retinal and nerve endings in the eye, that will give the blind the ability of sight.. or the giving birth to a new pancreas... doctors learning how to harness stem cells for regrowing teeth, understanding how cancer cells operate... It brings me back to that goofy star trek movie where they kidnap the whale from the 20th century, the Doctor Bones is horrified at the procedures they use to resucitate a victim of cardiac arrest or whatever, he views the whole procedure as barbaric medicine... I feel the same way about what's happening now, if only I could live to see through the revolution in medical science that's happening now. I'm probably too old though, being in my 30's, but one day I wouldn't be surprised if limbs and eyes could be regrown, cancer is understood and easily treated, a great number of ills to be cured... sigh, if only time were not an issue.
Isn't, uhm, everything tied to quantum physics?
Take off every sig. For great justice.
I share your general skepticism, but the theory is not unreasonable. To suggest that electrons tunnel when an odorant molecule docks in a receptor site seems reasonable enough. Of course the question is whether the signal from such an event is sufficiently above the noise. TFA is specifically about some calculations that suggest that the tunnelling rate should be reasonably high (and, crucially, should be quite different with vs. without the odorant molecule).
You are right about the established body of literature that already explains much of the sense of smell. However I think it's worth keeping in mind that the two explanations are not mutually exclusive. It sounds like even the scientists in question are treating it like this is an either/or situation, but there's nothing impossible about smell involving a combination of shape-specific molecular recognition and electron-tunneling-specific molecular recognition. Perhaps some shape is the general measurement and then electronic effects provide secondary information.
In any case, it sounds like it is worth some further investigation. There are still many unanswered questions. However, like you, I won't be investing just yet!
I am a neuroscientist who used to work on olfaction.
His theory is unconventional but it didn't break any known biological principles. Odors are detected by olfactory receptor *neurons* located on the olfactory epithelium inside the nose (for vetebrates). There are some olfactory receptor *molecules* on the membrane of these neurons - to the confusion of most people, both the neurons and molecules are sometimes called "olfactory receptors". The consenses for the last decade is that these molecules recognize the shape of odor molecules through chemcial interactions. The binding of the odor molecules to the receptors changes the membrane potential of the olfactory receptor neurons which then transmit the information to the brain.
What he is proposing is instead of, or in additional to, the chemical interactions, the olfactory receptor molecules can recognize the odorant molecules through quantal properties. It's unconventional but it is not totally implausible. The interactions between receptor molecules and agonist (the molecules that bind and activate the receptors) are molecular level events. I'm not a quantal physicist but weird things could perceivably happen at those levels. And after the olfactory receptor molecules being activated, the signal goes to the brain in the same way as the conventional theory.
The weakness of the theory is more since it's an unconventional claim, it needs more than usual proof. The experiment is not hard to do and after ten years, I haven't heard of a single high profile experimental paper to support it (I could have missed it). So, it probably should be classified as a neat but unproven theory.
Electrons, photons, and protons are all merely models to explain in tangible terms what the **** is going on down there, so I become skeptical when these terms are utilized to explain/demonstrate quantum mechanics.
Um, okay, we don't know everything about these particles, but all of those things are real things very much like we describe them -- we can count electrons, photons, and protons, and in the latter case we know they are comprised of smaller things called "quarks" that when combined correctly behave very much like the little ball we call the "proton". That's as real as anything. Quantum mechanics describes the behavior of electrons, so I'm confused as to why you would be skeptical that electrons are used to explain quantum mechanics. The topics are rather intricately linked.
I'm quite certain that there are layers upon layers beyond what we know, but at this time we don't know of any way to go deeper than the electron. Hence you're basically asking for something to be described in terms of knowledge that doesn't exist yet, which is impossible.
The enemies of Democracy are
You're basically right, though: Major oscillations between groups of neurons or anything like that is something radically different than this, and this theory doesn't make that any more likely. Even in that case, there is no reason to scream "quantum" (as in: impossible to handle with good old Newtonian physics/statistical chemistry/thermodynamics), as the main effects should be the varying electrical field, which we can easily measure with EEG electrodes. Some degree of leakage/overhearing is known, but I've no idea if anyone has found that as crucial to proper function, rather than a noise effect that's generally filtered out.
This theory is "revolutionary" because biochemists use classical simulations. Quantum mechanics is very difficult to apply to such large systems in practice but these molecules definitely are governed by quantum mechanics like all molecules.
Save the bandwidth. Don't use sigs!
Hold on just a minute. You are making quite a leap there, while acting as if you were just stating the obvious.
Unless you can do something along the lines of:
...you are just making an unsupported assumption there. You may think that free will doesn't sound like something that could come out of a system under the classical approximation, but that's nothing more than a hunch. There are undoubtedly countless logical consequences of classical physics that no one has worked out yet (and many times more that never will be worked out) so it is a bit premature to claim that something we can't even define isn't among them. (To put this in perspective, radio, quicksand, thunderstorms, slinkys, tubas, and static cling are all classical phenomena; do you really think you could fill in the rest of the list without missing many more than you capture?)
You're way off base on several other points as well (e.g. "instantiation" vs. "simulation" and the long ago exposed "Chinese Room" straw man), but I suspect you are only clinging to them because of your (unfounded) principle worry--that without some sort of magic escape hatch you are at risk of losing your free will to physics. Since this fear is unfounded, I won't bother with the secondary issues here.
--MarkusQ