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."

Raised eyebrows...

[BWJones]

I am going to be very skeptical of this and would not be tossing any money into a private company to study this just yet. The olfactory system is well capable of distinguishing many small molecules, even those that are very similar using a variety of well known and well understood processes just as in the immune system. Look, a Nobel prize was awarded back in the 30's for the discovery that IGGs can recognize even racemic molecules such as L and D forms of glycine even and the olfactory literature is just as rich. The biggest problem however, with the UCL approach is that it completely ignores years of cortical, subcortical and psychophysics data. Furthermore, there is no effort or model in their work that might explain how the signals would be transduced into cortical/subcortical signals or how they account for potential noise in the system. Their claim that signals can be translated through tunneling in a biological system which likely swamps those potential signals with noise is what really troubles me.

I am not saying that they should not do it, or that they are absolutely wrong, as it is possibly interesting. Rather all I am saying is my eyebrows are raised at their claims.

Re:Raised eyebrows...

[drinkypoo]

On the other hand, if it turns out to be true, it has far-reaching implications. A lot of people have been saying for a long time that quantum effects simply cannot be a factor in the brain, or causing neurons to fire or not, because their effect is too weak. This would be a counterexample and might cause us to look more seriously at quantum activity in the brain. One theory of the mechanism of memory is that it is stored as a series of quantum oscillations creating a sort of holographic pattern...

Re:Raised eyebrows...

[morgan_greywolf]

On the other hand, if it turns out to be true, it has far-reaching implications

Sure! It means that the smeller has an effect on the smelled! It also explains why Schroedinger never took into account the SMELL of that both dead and alive cat...

Re:

[Drooling Iguana]

I've been saying this all along! Whoever smelt it dealt it.

Re:

[mrogers]

I've been saying this all along! Whoever smelt it dealt it.

Unfortunately the Uncertainty Principle states that you can't simultaneously know what a fart smells like and where it came from. That explains why your own farts never smell as bad.

Re:

[somersault]

I don't think they had deathmatch in the 50s, so probably not

Re:

[jafac]

The problem is; my cat smells bad whether it's dead or alive.

Re:

[Vreejack]

The article is about olfactory receptors, not neurons. All the interactions described here are taking place where the external part of the olfactory receptor meets passing molecules. The actual news here is that the olfactory receptors might actually be capable of detecting quantum-level effects, unlike brain neurons which lack anything near the sensitivity required for that.

Re:Raised eyebrows...

[cnettel]

All chemical bonds are quantum-level effects. You're absolutely right that this is just about the receptors, and it would have been a great surprise if those did NOT show great specificity, with far more than simple sterical relationships. On the other hand, this also applies to just about every neuron junction, where you have specific receptors for neuropeptides. Those are just as much, or as little, quantum physics as this. In addition, just about every enzymatic system with some movement going on is naturally quite dependent on effects like these (and hence a pain to model, it's hard enough to get a static structure right).

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.

Re:

[Burz]

If quantum effects can be important in muscle-fiber actuation, why not elsewhere?

Smelloscope

[Khammurabi]

The whole idea of quantum smelling immediately brought Futurama to mind:

Cubert: I didn't realize you were the inventor of the junk heap!

Prof.: That's my price-winning Smelloscope. If a dog craps anywhere in the universe, you can bet I won't be out of the loop. And this is my Universal Translator. Unfortunately, it only translates into an incomprehensible dead language.

Cubert: Hello.

Translator: Bonjour.

Prof.: Crazy gibberish!

Re:

[Deus Acerbus]

"And therefore, by process of elimination, the electron must taste like Grape-Ade."

Re:

[shawn(at)fsu]

my eyebrows are raised
What about your nose?

Re:

[Walt Dismal]

I am not a neuroscientist, but I play one on TV. And I want to introduce my new, patent-pending, Electron Deodorant. Ladies, if your electrons stink like a two-week trout from New Jersey, you need ED! Men, if your pits kill hungry dogs at 45 feet, you need ED! Guaranteed to stop quantum entanglement for up to 24 hours or DOUBLE your filthy money back. Not sold under GPL. Recommended by noted physicists Oprah Winfrey and Richard Simmons, and Darl McBride, winner of the Guinness Book of Records Prize in Leg

Re:

[HappySqurriel]

I know far too little about quantum physics to comment on the plausability of any claims related to it but I also wouldn't be too surprised if this theory was true. My reasoning is quite simple, being that the classification of substances, objects and other animals has made the difference between life and death and evolution should (over millions of years) provide mechanisms to differentiate these items; if you need to be able to tell the difference between two gasses which are similar in all ways not relat

Re:

[Planesdragon]

if you need to be able to tell the difference between two gasses which are similar in all ways not related to quantium physics then a method related to quantium physics will have to be generated in order to survive.

Except that gases that are meaningfully different to us humans and other forms of life are different on a much greater than quantum scale. And the range of those gases that there is evolutionary pressure to detect is limited to those that appear with enough regularity in the terran biosphere to

Re:Raised eyebrows...

[kebes]

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!

Re:

[whathappenedtomonday]

Their claim that signals can be translated through tunneling in a biological system which likely swamps those potential signals with noise is what really troubles me.

Actually, there seems to be quite a lot of noise in our brain. [zdnet.com]

Re:Raised eyebrows...

[ywl]

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.

Re:Raised eyebrows...

[cnettel]

I wouldn't even call it that unconventional. There are lots of examples of ligand-protein interactions where you can't get the experimental affinity right, unless you make the energy-minimization time-dependent and compute the mean. This is not only a matter of the fact that the protein will adapt slightly when binding the ligand, but really that we have a continuous movement going on. A conformation where one vibration would suddenly be totally fixed, although it looks fine if you look at the static average, might be quite disastrous. This will be important if we ever want to be really good at engineering new enzyme specificities, or new ligands. Creating perfumes is of course a rather useless special case of the latter, and while it might be news to the odor industry, it shouldn't raise any eyebrows in the pharmeceutical industry. (At least if TFA is anywhere close to describing the actual theory...)

Re:

[Mr. Underbridge]

The notion that things with similar structures having different smells - well, things with different structures often have different chemistries. Often a slight change in structure has significant effect on shape, size, polarity, electronegativity, etc, and these things can have enormous impacts on the ability of an odorant to fit correctly with a G-coupled protein receptor, which are the proteins responsible for olfaction.

The notion that things with different structures smelling the same is irrelevant -

Re:Raised eyebrows...

[alkaloids]

IGGs can recognize even racemic molecules such as L and D forms of glycine

Ah, glycine is um, not chiral. Therefore you can't have an L or a D form, nor can you have a racemate... Close though! You were really unlucky, as glycine is the only AA that's not chiral.

As to the rest of the comment, I'll raise my eyebrows at it. I'm thoroughly skeptical that tunneling would be involved in smell though, but it would be amazing if it were. We'll find out soon enough I'm sure.

Re:Raised eyebrows...

[BWJones]

Dammit! Mad props to you as I was thinking alanine. That of course is exactly why Slashdot gets you in trouble. You type stuff in off the top of your head to get your entry in and sometimes you get it wrong. The cool thing is that there are folks on Slashdot that will catch you.

Re:

[blank axolotl]

I disagree. My (non-expert) impression is that this research is really about the physics of receptor (detector) proteins. The neural system is irrelevant because what we are worried about here is whether the receptor triggers a reaction or not. Once the receptor is triggered, the psychology is the same: a signal passing down the nerve into the brain.

The idea seems plausible to me, at least it is worth investigating. What it proposes is a new way a receptor could be triggered by a molecule. Here, once the mo

Re:Raised eyebrows...

[CapsaicinBoy]

I am a chemosensory psychophysicist, but I work in taste/chemesthesis, not smell. That having been said, I was in the room when Keller and Vosshall presented the following at the Association for Chemoreception Sciences meeting in 2004.

A PSYCHOPHYSICAL TEST OF THE VIBRATION THEORY OF OLFACTION
Keller A., Vosshall L.B. Laboratory of Neurogenetics and Behavior,
Rockefeller University, New York, NY

At present no satisfactory theory exists to explain why a given
molecule has a particular smell. A recent book about the physiologist
Luca Turin has generated new interest in the theory that the smell of a
molecule is determined by its intramolecular vibrations rather than by
its shape. We present the first psychophysical experiments in humans
that test key predictions of this theory. The results suggest that
molecular vibrations alone cannot explain the perceived smell of a
chemical. Specifically, we have found that: (i) in a component
identification task no vanilla odor character was detected in the mixture
of benzaldehyde and guaiacol (ii) odor similarity ratings did not reveal
that even and odd numbered aldehydes form two odor classes and (iii)
naive subjects who could easily discriminate the smell of two molecules
that differ in shape but not in molecular vibration failed to discriminate
two molecules with similar shape but different molecular vibrations in
three different experimental paradigms (similarity rating, duo-trio test,
triangle test). Taken together our findings are consistent with the idea
that the smell of a molecule is determined by its shape but we found no
evidence that the smell of a molecule is influenced by its vibrational
properties.

They subsequently published their findings in Nature Neuroscience.

Keller A, Vosshall LB. A psychophysical test of the vibration theory of olfaction. Nat Neurosci. 2004 Apr;7(4):337-8.

At present, no satisfactory theory exists to explain how a given molecule results in the perception of a particular smell. One theory is that olfactory sensory neurons detect intramolecular vibrations of the odorous molecule. We used psychophysical methods in humans to test this vibration theory of olfaction and found no evidence to support it.

The short version is that the data do not support Luca Turin's speculation.

Whole chemistry is based on quantum mechanics

[poszi]

I'm not a neuroscientist but I work on molecular interactions and the idea is not that far fetched. In general all interactions involve quantum mechanics. Protein folding, DNA helix, it all requires dispersion [wikipedia.org] which is a purely quantum-mechanical effect. I'd say the whole chemistry is immersed in quantum mechanics. Well, color can only be explained by quantum excitations, so why not smell?

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.

Re:

[nuklearfusion]

A quick search for isotope smell [google.com]reviled this [corante.com]
FTA

Three of his proposals took a good pounding: that mixtures of guiacol and benzaldehyde take on a vanilla odor not found in either compound alone, that straight-chain aldehydes with an odd number of carbons smell different from even-numbered ones, and that deuterated acetophenone smells different from the parent compound.

Although the article implies that a group took him apart on this idea, i suspect that this may be what Turin was referring to.

Re:

[niktemadur]

I'd love to know what an isotope smells like!

Burnt firecracker?

Re:

[BWJones]

OK rhombic. Look up Karl Landsteiner, who won the Nobel in 1930 for his work discovering the major blood groups and the development of the ABO system of blood typing. If you were remotely familiar with your science or history, you might suspect that immunology just *might* be part of this work. Specifically, he discovered that agglutination was an immunological reaction and that specificity of the antigen is so good, that one can discriminate racemic molecules. Of course this work was the most medically

Re:

[rhombic]

Yep, Landsteiner got the Nobel in 1930 for ABO typing-- nothing to do w/ chiral recognition. That work was done later with van der Scheer, in the 20's, not part of the ABO work & not what the Nobel was awarded for. I am remotely familiar w/ my science in this area ;). And a little bit of the history, too.

Understood about confusing glycine & alanine, but when you're pointing out chiral recognition and you choose as an example the one and only non-chiral amino acid, somebody's gonna call you on it.

Been rooting for this guy!

[RobertB-DC]

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 [flexitral.com]. 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.

Re:

[Vellmont]

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.

I guess I'd be impressed if he actually did science and came up with an experiment or series of experiments that showed that his theory was correct, and the old theory is incorrect.

Since we presumably don't have any idea how his scent cre

Re:Been rooting for this guy!

[Otter]

Here's a good discussion [corante.com] of Turin's work as it stood a few months ago. I agree with Lowe that Nature Neuroscience's trashing of him was excessive and obnoxious, particularly because, as you say, there's no question that he behaves like a responsible scientist pushing a wildly controversial idea should.

Re:

[linuxscrub]

There was a book written on this guy, about 4 years ago:

The Emperor of Scent: A True Story of Perfume and Obsession by Chandler Burr

While not a technical book, it does cover the mass-spectrometer-in-your-nose thing at some level. It's a good read, as it covers the guy, his idea, the fairly radical nature of the idea, and it's fairly small effect thus far (up to the point the book was written).

ls

Re:

[Anonymous Coward]

Being successful doesn't automatically mean you're right.

I can claim that my soda channels psychic vibrations to the part of your psyche responsible for taste, and that's why it tastes better better than the competition's drink. Or it might be that I used cane sugar instead of corn syrup.

Hmmm

[Anonymous Coward]

Does that mean that Schroedinger's cat may or may not smell like a corpse if it's dead?

So... Umm...

[vertinox]

If I haven't gotten a whiff of my cat's litter yet, it is in neither state of smelling fresh or stinky?

Or if it does smell stinky, I can be certain in another universe it smells like roses?

Re:

[Duggeek]

But in that other universe, roses smell like cat-doo...

Unthinkable in the other universe, since it's normal there, unless they also have Slashdot...

If they do, then it's called Slatdosh and instead contains incessant blathering about irrelevant topics...

Oh... hang on a bit...

Maybe Slashdot itself is a portal to parallel worlds?

sometimes I feel like I was born too late

[Adult film producer]

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

Re:

[vertinox]

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.

Well if you believe in Quantum Immortality [wikipedia.org] then chances are you can only exist in a universe that such events happen in which scientific progress lets you exist forever.

As were all thos

Re:sometimes I feel like I was born too late

[Tyger]

Besides if you are 30, by the time you are 70 it will be 2076 and if you consider all the progress made from 1906 to 1946 it will be at least interesting.

Wow, a post from the future! What's it like in 2036?

Re:

[vertinox]

Wow, a post from the future! What's it like in 2036?

Whoops! Sorry about that!

Either my typing is wrong, or I am a traveler from the future and forgot what year I am in and you won't live long enough to enjoy the benefits of future science.

For those of you over 30 ignore what I just said.
For those of you under 30... Welcome to the world of tomorrow!

Re:

[tandr]

Wow, a post from the future! What's it like in 2036?

check yourself
http://johntitor.strategicbrains.com/ [strategicbrains.com] :)

Re:

[Ruie]

Wow, a post from the future! What's it like in 2036?

Well, when there is a dupe on Slashdot we can post directly to the original ! And we have arguments about whether the 1Gbps data limit is due to MAE-West or the entangled packet link somewhere in New Jersey.

Imagine the Implications!

[ArcherB]

This means that my ass can change the quantum state of that burrito I had for lunch!

Can I be the first to say...

[ErikTheRed]

... I think this theory really stinks.

tied to quantum physics

[eobanb]

Isn't, uhm, everything tied to quantum physics?

Re:

[drinkypoo]

Well, quantum physics is just a model. We'll probably find out later on down the road that we're all just figments of the highly detailed imagination of a resident of Snarfblatt IV and our "universe" will cease to an end one day as he is run over by a passing Warfleblorter.

*shakes his head* This is why people need to take Warfleblorting safety seriously.

Re:tied to quantum physics

[Oriumpor]

A poet once said, "The whole universe is in a glass of wine." We will
probably never know in what sense he meant that, for poets do not write to
be understood. But it is true that if we look at a glass of wine closely
enough we see the entire universe. There are the things of physics: the
twisting liquid which evaporates depending on the wind and weather, the
reflections in the glass, and our imagination adds the atoms. The glass is
a distillation of the earth's rocks, and in its composition we see the
secrets of the universe's age, and the evolution of stars. What strange
array of chemicals are in the wine? How did they come to be? There are the
ferments, the enzymes, the substrates, and the products. There in wine is
found the great generalization: all life is fermentation. Nobody can
discover the chemistry of wine without discovering, as did Louis Pasteur, the
cause of much disease. How vivid is the claret, pressing its existence into
the consciousness that watches it! If our small minds, for some
convenience, divide this glass of wine, this universe, into parts --
physics, biology, geology, astronomy, psychology, and so on -- remember that
nature does not know it! So let us put it all back together, not forgetting
ultimately what it is for. Let it give us one more final pleasure: drink it
and forget it all!

        - Richard P. Feynman, The Feynman Lectures on Physics, v. 1, p. 3-10
            (This lecture is also one of the six lectures featured in a book &
            audio edition entitled "Six Easy Pieces")

Re:

[fahrbot-bot]

A poet once said, "The whole universe is in a glass of wine."

This poet obviously never got stoned, otherwise he would know that the Universe is actually in his thumb.

Damn non-hippie.

Subatomic physics, on the other hand, is in beer.

[Ungrounded Lightning]

A poet once said, "The whole universe is in a glass of wine."

On the smaller end of things, subatomic physics is in a glass of beer.

For instance: The bubble chamber detector for moving charged particles was invented by a physicist while he was sitting at a restaurant near the University of Michigan and wondering what started the bubbles in the beer forming.

Ultimately, yes, but not immediately

[jfengel]

At the bottom, yes. This is trying to show that QM is involved more directly than the usual explanation.

The usual explanation for smell is the lock-and-key hypothesis: a specific receptor fits a molecule of a specific shape. It's similar to (and in fact related to) the immune response. QM is involved, but only in the way the molecules fold and interact, so the QM is all wrapped up by plain old chemistry.

This explanation invokes QM more directly, in a way that can't be explained by plain old chemistry. It co

Re:

[lawpoop]

Prove it.

You'll get a Nobel prize and a place in history for telling us exactly how.

Re:

[lawpoop]

Yes and no ;)

Re:

[AK Marc]

Isn't, uhm, everything tied to quantum physics?

And even a 747 is covered by the Heisenberg Uncertainty Principle. The more accurately you know how fast the plane is going, the less sure you are where it is. But, for "real life" the effect is so small for a 747 that it is useless to consider. Newtonian physics is all that's really necessary for the vast majority of regular life. The newer and more accurate descriptions of the universe are usually too complicated and too accurate for real world use.

Re:

[hey!]

Laying down the semantic guantlet are we?

OK then, I'll pick it up:

The sense of smell cannot be modelled adequately without including quantum phenomena in the model.

Sooner or later the blind watch maker is going to pick some quantum doohickey out of the toolbox.

Doing quantum physics...

[NoseBag]

...with our nose!

That's nothing to sniff at.

That's makes farting sense...

[__aaclcg7560]

...suggests that electron tunneling initiates the smell signal being sent to the brain.

That would explain why I could evacuate a room about 30 seconds before the smell of one of my roommate's horrendous "floorboards" hit everyone else in the room. The bewildered expression on everyone's face when I ran out the room but before they got hit was priceless.

Shouldn't that be...

[TheWoozle]

...this theory makes scents?

Re:

[davidsyes]

Damn, too bad I already commented. I'd have bumped you up from 0, Offtopic to 1 of 2... SHEESH, where is the HUMOR around here?

Quantum Chemistry

[opencode]

The UCL team calculated the rates of electron hopping in a nose receptor that has an odorant molecule bound to it.

--

He had me until this sentence (although the line that he found the theory interesting enough to refute was a very nice touch).

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. We know how to use electricity, buy it, sell it,

Re:

[greg_barton]

It's gotta sound really strange or it's not QM/C.

And it's gotta be comprehensible to the layman or it'll never get past an editor.

Why don't you read the original paper instead of dismissing the research based on account filtered through the lay media?

Re:

[pclminion]

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. We know how to use electricity, buy it, sell it, how to protect our kids from it, yet we really don't know what it is.

I think you're making the classic mistake of, "The math is hard and unlike other math I've seen before, therefore QM is strange and mysterious." It should come as no surprise

Re:Quantum Chemistry

[Chris Burke]

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.

Re:

[diqrtvpe]

Now, IANAQP, but I am a Physics student, and I have had reasonable experience with quantum tunneling. From what I've learned, quantum tunneling is most easily described in terms of electons hopping across barriers. The electron has a non-zero probability of being found outside the potential well created by its parent atom/molecule, and (skipping over most of the science and math) this means that there will be a non-zero rate of tunneling from that well to the other wells nearby. Now, in many cases that r

Re:

[me_mi_mo]

You keep repeating that things like photons, electrons and the like are "merely models". I have to take issue with this, as they happen to be effective models.

I would *love* to see how you would *begin* to explain how light and matter interact at a *fundamental* level, without using the concept of electrons and photons.

These guys are not cranks - the (free, as in beer) preprint [arxiv.org] seems to be a pretty typical quantum transport paper, albeit with a slightly "sexed up" angle.

Models are good, if they wo

Re:

[chreekat]

Well, don't forget that one of the concepts that makes QM so weird is that "things" (unfortunate terminology) aren't particles or waves of energy... they are both. Since this is weird, you have 'electron clouds' that represent probability or 'orbitals' that represent the different energy distributions in a quantized way, etc. etc., all trying to describe reality.

Anyway, the point is that electrons "are"/"can be" distinct, quantized doohickeys, so saying that 'the electron hopped' isn't physically inaccurate

Okay, let's get this out of the way....

[Itninja]

...by biophysicist Luca Turin

I hear his (her?) work is SHROUDED in mystery. Zing!
I'm here are week folks....

Busted webpage?

[Antony-Kyre]

Anyone else experiencing the webpage reloading itself endlessly?

Go to http://www.nature.com/news/2006/061204/pf/061204-1 0_pf.html [nature.com]

Re:

[Antony-Kyre]

Nope. Other stuff doesn't work with the page. I haven't tried Firefox yet.

Credit to Richard Lederer

[edp]

"The article concludes, 'At the very least, he is putting his money where his nose is.'"

His scents sense makes cents.

Nose candy

[HTH NE1]

His scents sense makes cents.

Really? To me, "putting his money where his nose is," is more easily interpreted as a euphemism meaning he's addicted to cocaine, and thus is a turn of phrase that should be avoided unless you want to be sued.

Re:

[aaza]

To me, "putting his money where his nose is," is more easily interpreted as a euphemism meaning he's addicted to cocaine, and thus is a turn of phrase that should be avoided unless you want to be sued.

Really? To me, "putting his money where his nose is" is more easily interpreted as "putting his money where his mouth is" (ie putting cash on the line to back a statement) but using "nose", since this is about smells.

Maybe it's because I'm not from the USA that I don't immediately think of drugs and slander

Re:

[HTH NE1]

Maybe it's because I'm not from the USA that I don't immediately think of drugs and slander/libel and suing people.

No, it's just you're not so much of a paranoid pessimist as I am. I tried to turn it into a cautionary tale using dark humor which, judging by the moderation, I failed miserably at this time.

My point was how easily a clever turn of phrase can be misinterpreted and offense registered:

"How fast does the poison work?"
"Very quickly, he said. Almost instantaneously."
"'Almost'? How fast is almost? T

Penrose and Quantum Consciousness

[DoninIN]

Wasn't one of the rebuttals to Penrose's books that there couldn't be any quantum processes at work in the brain because of (reason X)[1] I wonder if anyone knows enough to comment on this? 1: Basically quantum effects were supposed to be too small? I really can't remember.

Re:

[chreekat]

Sure, I'll take a swing at it (my credentials are shaky -- a BS in computational physics). This theory says that tunneling, a quantum mechanical process, lets an electron jump into the nervous system. That's equivalent to saying that a quantum mechanical process causes an electric current... something the nervous system uses extensively. I don't know if a single electron would be enough to trigger a signal, but two possibilities for the theory are (1) it *is* enough, (2) more than one electron tunnels.

Pleas

Re:

[man_ls]

If a single electron "jumping the gap" is enough to change the electrochemical gradient to above the activation threshold of the neurons and cause depolarization, then you're absolutely right -- it would be inducing an electric current. One electron isn't a whole lot, however -- you'd need the combined effects of thousands of the things to produce enough of a change in the neuronal environment to really make a difference.

Re:

[Ungrounded Lightning]

I think the point of the criticisms of Penrose isn't over whether quantum-mechanical stuff is going on, but whether quantum-mechanical wierdness (such as entanglement) is involved in the brain's computations or whether they can be fully explained by the classical physics and chemistry approximations (and can thus be adequately modeled by algorithms run on ordinary computers rather than requiring a quantum computer).

Re:

[wytcld]

That's right. But consider: if it can be fully explained by the classical physics approximations, then by the laws of causal closure included there we cannot possibly have free will, and we're left with the falsely-named "Cartesian" split that leaves no explanation for consciousness having any causal powers at all (which leaves the evolution of consciousness rather unexplained). However, if quantum laws are required to explain our brains, then arguably those laws bring in a recognition of consciousness as b

Slow down there buddy

[MarkusQ]

if it can be fully explained by the classical physics approximations, then by the laws of causal closure included there we cannot possibly have free will

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:

1. Say exactly what free will actually is.
2. Explain how to work out the consequences of applying the laws of classical physics in every possible physical system (possibly lumping systems together

Re:

[Ungrounded Lightning]

That's right. But consider: if it can be fully explained by the classical physics approximations, then by the laws of causal closure included there we cannot possibly have free will ...

Doesn't say that to me... ... there's nothing [in classical mechanics] like the impossible gap [in quantum mechanics] which the classical approximations can't resolve.

Quite the contrary: You can hide free will just as easily behind the chaos barriers of catastrophy theory as you can behind quantum mechanical uncertainty. Th

Re:

[SQL Error]

Max Tegmark wrote a paper showing that the time for quantum decoherence in the brain was ten orders of magnitude too short for any sort of quantum computation to have an influence on consciousness (or any other brain function).

Which doesn't mean that there aren't quantum processes at work in the brain - there are, as in any physical system. It's just that they give rise to consciousness through the normal course of biochemistry, rather than through magic, as Penrose would have it.

Why quantum?

[asadodetira]

Quantum level models are very limited in the lengthscales and timescales they are able to model. Shouldn't they first try a slightly less microscopic explanation, based in molecular dynamics that should be easier to verify. You still can have rich dynamics, with vibrations and rotations and diffusion and changes in configuration that might account for the different interactions between the receptor and the odorant.

Can't just be vibrational tunneling

[imkonen]

It's a cool theory, but it can't be the only affect, because it doesn't explain how different enantiomers of the same molecule could smell different. Carvone [wikipedia.org] for example, smells like caraway or spearmint depending on which of two mirror image forms it's in. Each of these forms has the identical vibrations (both in terms of frequency, atomic displacement, and transition dipole), but would "lock in" differently with biological molecules, almost all of which are chiral (and pure enantiomers). The "shape spe

Re:

[seanellis]

The vibrational states of the enantiomers should be identical, but this is only true when measured in isolation.

Remember that the "measurement" happens when the compound is attached to the receptor protein. The binding site will very likely be asymmetric and thus bind differently to the two enantiomers, and this will affect the vibration / electron tunneling properties differently for each. This should allow them to be distinguished.

I believe it

[Fear the Clam]

The guy on the subway tonight had some serious quantum funk coming off him. It's as though every particle was trying desperately to get away and warn the others.

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[bishiraver]

You weren't on the 5 train uptown between grand central and 59th st, were you?

If so, I think we saw the same guy...

Re:

[Fear the Clam]

As a matter of fact, I was.

I think it was the great philosopher Morpheous

[phreakincool]

who said it best. "You think that's air you're breathing? Hmmm."

nnrgh...

[TobyRush]

[Trying to figure out some "+5 funny" remark tying this to quark "flavors"]

Strange? Charm?

[Cryolithic]

Gives a whole new meaning to strange or charming smells!

Ugggh!

[netglen]

You changed the outcome by observing it's smell.

I'm coming up with a theory that the quality of

[davidsyes]

scex is based on the durability, flexibility and viscosity of the quantum slipstream (thank you "Star Trek" with all the techno babble...). Then my mind thought of Mr. Ears... "Once upon a midnight dreary, while I pounded weak and weary..." when Charlie hexed me....

I have determined that the physicality, umm, err, the physics involved make scents... umm, sense, but legally, it does not pay to do this research to make cents.

Energy can be derived from various forms of matter, possibly even dark matter. But, l

Maybe the sense of taste is as well?

[Sperlock]

If this is true for the sense of taste as well, it would explain why so many things taste like chicken.

What about Axel and Buck theory?

[dockingman]

I'm a graduate student in Computer-Aided Drug Design, and as part of my degree I did a research proposal on prediction of smell with computers.

Richard Axel and Linda Buck received their Nobel Prize in 2004 for Physiology or Medicine for "for their discoveries of odorant receptors and the organization of the olfactory system". Note that this is not *only* for the discovery of the receptors, but also for the *way they work*. There are hundreds of receptors in mammals (almost 1,000 in mice, about 330 in humans) that have different selectivities for different odorant molecules and act combinatorially, that is, that the signal perceived by the brain is the result of the combination of receptors activated by the odorant. Given the large number of receptors, and that any number can be activated by an odorant, the variety of smells is huge, and on the other hand the promiscuity of the receptors allows for a chance of 2 dissimilar molecules having the same smell...

Some literature I suggest for someone interested:
- Nobel Prize illustrated presentation: http://nobelprize.org/nobel_prizes/medicine/laurea tes/2004/illpres/ [nobelprize.org]
(see also the Nobel Lectures therein)
- Unpredictability of smell: Sell, C. S. Angew. Chem., Int. Ed. 2006, 45, 6254-6261.

I really think that the system of smell is already quite strongly explained by this theory, that also follows the classical binding+activation of receptors that drives traditional biochemistry and drug design.

I'm still surprised that some theoretical chemist/physicist didn't do QM calculations to prove the tunneling, and publish it in a leading peer-reviewed journal, if the theory is so sound...

Moo

[Chacham]

I both agree and disagree with this article, and although it looks good, it smells bad.

I think i'll ask my cat what it's all about.

Didn't Ms. Vega predict this?

[inviolet]

The theory, proposed in the mid-1990s by biophysicist Luca Turin, suggests that electron tunneling initiates the smell signal being sent to the brain.

My name is Luca.
I live on the second floor.
I live upstairs from you.
Yes, I think you've seen me before.
If you smell something late at night
Some kind of molecule,
Some kind of quantum function;
Just don't ask me what it was,
Just don't ask me what it was,
Because I haven't published yet.

Oh please

[kalirion]

FTA: It could explain why similarly shaped molecules can have very different smells, and molecules with very different structures can smell similar.

The guy has obviously never heard of hashing.

Great book on this theory

[andrewzx1]

A book has already been written on Luca Turon's controversial theory of smell. it's a great read! http://www.amazon.com/Emperor-Scent-Story-Perfume- Obsession/dp/0375759816/sr=8-3/qid=1165952555/ref= pd_bbs_3/105-9158177-5828428?ie=UTF8&s=books [amazon.com]

Re:

[TheLink]

An organism has an advantage if can create a model of its environment, predict outcomes and make a good choice.

And that's where brains/minds come in. I suggest that brains are not so much neural networks that do fancy pattern matching etc, but more of systems that model stuff.

When brains start needing to model brains including themselves that's where things get interesting. If brains start to try to model a Creator that could get even more interesting ;).

There seem to be many ways where quantum physics/comp