Quantum Mechanical effects observed in algae

[Jet Black]

There has been some speculation for a while now that quantum mechanical effects have been exploited by living organisms, particularly in photosynthsis, in which electron transfer is often far more efficient than one would expect by random hops alone, and a number of experiments have already observed QM effects in organisms

http://www.sciencenews.org/view/feat...Living_Physics

Now a group in the University of Toronto have observed superposition states in algae - a purely quantum mechanical state.

http://www.sciencedaily.com/releases...0203131356.htm

The exploitation of Quantum mechanics by living organisms is really cool, since room temperature highly complex systems have not really been considered to be a good situation for QM effects to be a significant factor. Most experiments that we do to observe Quantum Mechanics tend to be very cold, or limited systems involving small collections of atoms and photons, but now we can see that nature has been doing this stuff for billions of years.

[RAFH]

Does this involve the Vacuum Energy of the Plenum as used by the NGEs to diddle the genomes of embryos?

[Febble]

Originally Posted by Jet Black

There has been some speculation for a while now that quantum mechanical effects have been exploited by living organisms, particularly in photosynthsis, in which electron transfer is often far more efficient than one would expect by random hops alone, and a number of experiments have already observed QM effects in organisms

http://www.sciencenews.org/view/feat...Living_Physics

Now a group in the University of Toronto have observed superposition states in algae - a purely quantum mechanical state.

http://www.sciencedaily.com/releases...0203131356.htm

The exploitation of Quantum mechanics by living organisms is really cool, since room temperature highly complex systems have not really been considered to be a good situation for QM effects to be a significant factor. Most experiments that we do to observe Quantum Mechanics tend to be very cold, or limited systems involving small collections of atoms and photons, but now we can see that nature has been doing this stuff for billions of years.

Can you translate this into something that would make sense to me?

[Jet Black]

Originally Posted by Febble

Can you translate this into something that would make sense to me?

Well in the case of photosynthesis, when a photon excites an electron, it was thought that it propagated through the protein, molecule to molecule through random hops through the molecular structure to its destination, but it turns out that this is not the case. What happens is that it follows a quantum mechanical path, in which it tries all of the routes at once, and then passes through the easiest one (the path of least resistance). This method of traversing the molecular structure is far more efficient than a classical kinetic process.

It is also thought that similar quantum mechanical effects might occur in vision, such as in the cryptochrome protein in birds eyes, which can be affected by weak magnetic signals.

does that make sense now?

[Febble]

Originally Posted by Jet Black

Well in the case of photosynthesis, when a photon excites an electron, it was thought that it propagated through the protein, molecule to molecule through random hops through the molecular structure to its destination, but it turns out that this is not the case. What happens is that it follows a quantum mechanical path, in which it tries all of the routes at once, and then passes through the easiest one (the path of least resistance). This method of traversing the molecular structure is far more efficient than a classical kinetic process.

It is also thought that similar quantum mechanical effects might occur in vision, such as in the cryptochrome protein in birds eyes, which can be affected by weak magnetic signals.

does that make sense now?

Yes, thanks

[Jet Black]

Originally Posted by Febble

Yes, thanks

that was disappointingly easy

[sfs]

The news story is pretty over the top. It's not exactly newsworthy that an organism depends on quantum effects -- every chemical bond depends on quantum effects, after all. What's unusual is that a chemical process in this organism involves a superposition of states, which is a strictly quantum behavior, with macroscopic results. But it's not like the algae are consciously manipulating quantum states; they produce a complex of molecules, and that complex has this behavior when exposed to light. Quite possibly the complex has been fine-tuned by selection, if they're right about it being more efficient, but the fact that it involves coherent superposition is irrelevant to the biology -- all that matters is the efficiency.

[jasona]

Do you think that similar adaptation to QM might occur in, say, the electron transfer chain in mitochondria?

[jasona]

ETA: tres cool. Nice to see real world support for the craziness that is QM.

Say, Jet Black (and others), what is a current, realatively up to date book on current physics that might catch me up? I was thinking of rereading "A Brief History of Time" but folks quickly shook me off that, saying it was too dated.

[Gagundathar Inexplicable]

My first thought on this was 'how can we harness this to make a room temperature quantum computer'?

[Jet Black]

Originally Posted by sfs

The news story is pretty over the top. It's not exactly newsworthy that an organism depends on quantum effects -- every chemical bond depends on quantum effects, after all. What's unusual is that a chemical process in this organism involves a superposition of states, which is a strictly quantum behavior, with macroscopic results. But it's not like the algae are consciously manipulating quantum states; they produce a complex of molecules, and that complex has this behavior when exposed to light. Quite possibly the complex has been fine-tuned by selection, if they're right about it being more efficient, but the fact that it involves coherent superposition is irrelevant to the biology -- all that matters is the efficiency.

I think the criticism re: chemical bonds is somewhat pendantic.

[jasona]

Originally Posted by jasona

Do you think that similar adaptation to QM might occur in, say, the electron transfer chain in mitochondria?

I do not want for this to be lost.

[Jet Black]

Originally Posted by Gagundathar Inexplicable

My first thought on this was 'how can we harness this to make a room temperature quantum computer'?

the problem here is that we are only talking on the scale of molecules and specific effects regarding light harvesting. Quantum computation would require coherence to be maintained and controlled over much larger time and length scales.

[Worldtraveller]

Originally Posted by jasona

ETA: tres cool. Nice to see real world support for the craziness that is QM.

Say, Jet Black (and others), what is a current, realatively up to date book on current physics that might catch me up? I was thinking of rereading "A Brief History of Time" but folks quickly shook me off that, saying it was too dated.

I'm certainly no expert either, but I rather enjoyed 'The Elegant Universe'. It gives a very good (IMO) rundown of our current understanding in the first few chapters....the stuff we do know fairly well. The other 2/3rds or so of the book describes the mathematical models that lead to membrane hypothesis and other crazy stuff that it looks like the universe does. I like that it proposes some possible tests. Most are still a bit beyond our technological grasp, but we are slowly approaching.

I'd also recommend the DVD (or look online, I think NatGeo carried it at one point.)

[sfs]

Originally Posted by Jet Black

I think the criticism re: chemical bonds is somewhat pendantic.

Obviously I don't, or I wouldn't have made it(*). I think the QM effects that lead to atomic orbitals and all of chemistry are just as nonclassical, counterintuitive and weird as this kind of superposition. They just don't get any press because we're used to them.

But I'm biased by a background in particle physics -- I just don't find quantum superposition to be very exciting.

(*) Okay, in reality I often knowingly offer pedantic criticisms. But not this time!

[Gojira]

Originally Posted by jasona

I do not want for this to be lost.

I'm not a biologist, and it's been 30 years since I studied QM in detail , but I'd be slightly surprised if a similar adaptation didn't occur.

[Jet Black]

Originally Posted by sfs

Obviously I don't, or I wouldn't have made it(*). I think the QM effects that lead to atomic orbitals and all of chemistry are just as nonclassical, counterintuitive and weird as this kind of superposition. They just don't get any press because we're used to them.

But I'm biased by a background in particle physics -- I just don't find quantum superposition to be very exciting.

(*) Okay, in reality I often knowingly offer pedantic criticisms. But not this time!

I think the clear point here is that quantum processes leading to atomic binding and such clearly do happen all the time, and so we do not pay much attention to them, and also they can be considered in a somewhat trivialised classical manner. Things like superposition do not occur in any way familiar to us. The reason this sort of thing gets more press is because it is occurring at a much larger scale in terms of the molecular sizes, and the whole molecule has evolved in such a way as to exploit it. I think it is also an important first example that things like this are well worth investigating, though I think that if they do find that vision is being manipulated in cryptochrome proteins, then that sort of thing would be much cooler.

[Linus]

Originally Posted by sfs

Obviously I don't, or I wouldn't have made it(*). I think the QM effects that lead to atomic orbitals and all of chemistry are just as nonclassical, counterintuitive and weird as this kind of superposition. They just don't get any press because we're used to them.

I see what you mean. The electrons in any piece of metal are delocalized over macroscopic distances. At least at very low temperatures. And that's probably what makes this noteworthy: a relatively long-lived coherent superposition at high temperature in a messy environment.

[TestyCalibrate]

[mod]derail split to here:
http://talkrational.org/showthread.php?t=22758[/mod]

[TestyCalibrate]

Originally Posted by jasona

ETA: tres cool. Nice to see real world support for the craziness that is QM.

Say, Jet Black (and others), what is a current, realatively up to date book on current physics that might catch me up? I was thinking of rereading "A Brief History of Time" but folks quickly shook me off that, saying it was too dated.

too dated. What level of abstraction are you comfortable with?

[Jet Black]

Originally Posted by jasona

ETA: tres cool. Nice to see real world support for the craziness that is QM.

Say, Jet Black (and others), what is a current, realatively up to date book on current physics that might catch me up? I was thinking of rereading "A Brief History of Time" but folks quickly shook me off that, saying it was too dated.

which bit of physics?

This sort of thing has been observed in QM before, but this is the first time it has been observed to be occurring in a biologically relevant sort of way.

[jasona]

Originally Posted by TestyCalibrate

too dated. What level of abstraction are you comfortable with?

I know what integrals and differential equations are but don't ask me to use them under pressure without reference texts to consult.

[TestyCalibrate]

Originally Posted by jasona

I know what integrals and differential equations are but don't ask me to use them under pressure without reference texts to consult.

I'm not sure. I think to be 'caught up' even relatively, you'd need to read journals and probably be academic about it even. However, I found 'the road to reality' by penrose to be exceptional at providing the background to help place new discoveries in their spots in the overall matrix of physics. Like J.Black says, 'which physics?'
road to reality does get a bit dense though and a reasonable understanding of calculus and differentials is pretty much required. I've come to the conclusion that all of math and physics pretty much is in there but you only see the parts you understand at the time. I go through it a lot when I'm reading new physics papers.

one of the one star reviews is accurate:

I am a big fan of Roger Penrose's earlier books. I had great hopes for this new book. What a huge disappointment.

This book is being played up as a book that an intelligent general reader can follow, but this is not true. The preface starts out by talking about something simple, fractions. Some chapters later the text rockets to things like(I quote):

"If H were a *simple* bivector, so that the 2-form H# would also be simple, then the 2-plane element determined by H# would be precisely the same as the 2-plane element determined by H. On the other hand, the index-raising that takes us from a 2-form Hab to a bivector Hab = Hcd gca gdb, has a more significant geometrical effect. The Hodge dual, as applied to the 2-form Hab, taking us to eabcd Hcd, i.e. to H#, employs the index raising Hab --> Hab, and therefore involves passing to the orthogonal complement..."

I chose this qoute for 2 reasons.

1) The math notation is simpler than most of the many other formulas in the book, so I could at least approximate it usind my keyboard.

2) I have a friend in math graduate school (yes, graduate school) and he glanced through the book and stopped in this chapter to tell me he had only recently been taught this stuff. I can handle some math, as in Penrose's earlier books. The math used here is much more advanced and much more central to the book.

Can you get a little something by skipping all the math? A very little. You are told a few things about math, its history, and its application to physics. But you can't learn anything as the explanations for everything you are told are based in the math that you can't read (unless high level math is your thing). Books for the general (intelligent) reader should not use grad level math. If they do, they should advertize that they do. This is not a cheap book and I could read so little of it. What a horrible disappointment.

however, if you want a basic outline of the fields within math and physics, it does a great job.

Do not confuse it with this road to reality.

Weirdly, I had to read Einstein to understand Penrose. If you haven't read Einstein's stuff on GR, I recommend "A Stubbornly Persistent Illusion."