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Photosynthesis May Rely On Quantum Effect
forgethistory sends us to PhysOrg for a summary of new research suggesting that the near instantaneous energy transfer achieved by photosynthesis may rely on quantum effects. From the article: "Through photosynthesis, green plants and cyanobacteria are able to transfer sunlight energy to molecular reaction centers for conversion into chemical energy with nearly 100-percent efficiency. Speed is the key — the transfer of the solar energy takes place almost instantaneously so little energy is wasted as heat. How photosynthesis achieves this near instantaneous energy transfer is a long-standing mystery that may have finally been solved."
I don't know about consciousness, but in his novel Blue Mars (last book of the Mars trilogy), published a decade ago already, Kim Stanley Robinson made use of research that suggests that memory relies on a quantum effect.
All interactions at the atomic level are quantum effects. A photon can only interact through quantum effects. The statement in the article is totally meaningless.
We have known that photosynthesis is a quantum effect since Einstein's paper on black body radiation.
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I can't seem to find the link (Google is not friendly today), but does this perhaps justify the researcher who postulated that the sense of smell comes from something akin to detecting nuclear resonance, not a simple chemical interaction? I recall that one detractor said that his theory was as outlandish as saying that food was digested in the stomach via tiny nuclear reactors. But it explained many things that didn't make sense otherwise -- like why cyanide smells like almonds.
He's apparently gone on to success in the perfume industry.
Someone find the link... this is driving me nuts.
Stressed? Me? Of course not. Stress is what a rubber band feels before it breaks, silly.
Would that mean that attempts to upload human minds to computers would fall foul of the no-cloning theorem? Such constraints on the duplication of quantum information would have interesting effects on philosophical problems of identity.
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Why do you need to invoke one mystery to "explain" another? I can't see why consciousness "may not be so easily explained without taking into account quantum effects". What particular things about consciousness seem to indicate quantum effects to you?
Other people have proposed this before, but present a theory of why quantum effects may be necessary. Roger Penrose makes the argument that we can compute things that a Turing-style computer could not compute, so something else must be going on. His proof that some things we do cannot be done by a Turing style computer isn't exactly accepted though, and no-one seriously believes that the brain works in this way in any case.
Also, consciousness is not the same thing as "self-awareness". Is a dog conscious? Is it self-aware? What about a rabbit? When I dream, I'm not usually self-aware, but there's some sort of consciousness there. What about phenomena like blind-sight, where a person is self-aware, but unconscious of visual information, even though they can access that information by guessing remarkably accurately, just without any direct consciousness of it. Does this mean that these supposed quantum-consciousness effects have broken down only for information originating in visual centers, but keeps working on all other information?
Of course, coming from quantum theory, there is the Copenhagen Interpretation which places a special status on the 'observer' - but no-one has managed to define what an observer is, or whether they must be conscious or not.
Maybe a better summary would be that the energy transfer in photosynthesis is handled by a very long lived wavelike electronic quantum coherence. Regardless of what everyone on /. thinks, this is a pretty big deal. Suggesting something is likely or even almost certain is not the same thing as proving it.
Yes, but while knowing the mechanism netted someone their PhD (or some PhD their tenure,) a workable implementation will net some company billions of dollars. Nearly 100% efficient solar cells? Yes, please. Pass the chlorophyll over here.
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But one thing we should also realize is that, nature has not produced a more efficient photosyntesis process. Plants do not use their energy for mobility. Just to grow. Growth is limited by other resources like minerals and water. So there might not be additional survival value in developing a more efficient photosynthesis process. But still we should be open to the possibility that 2% efficiency is probably the maximum for photosynthesis, using water+co2, producing C12H22O11 (sugar) and oxygen.
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
Well, that's only part of the story. The original capture loses very little energy...
1) If and only if the photon is of the proper energy. In general, during solar energy conversion of all kinds, you require a certain amount of energy to kick an electron out of the pigment. Less than that energy, and nothing happens. More than that energy, and the excess is wasted.
2) This only applies to the original photon capture. The total process of turning solar energy to sugars in plants is about 35%. Due to losses for biochemistry, the overall system is very inefficient -- usually just 1-2% in most crop plants, and a fraction of a percent in non-crop plants. Sugarcane is exceptionally high at 8%, still well below most silicon cells.
Now, dye-based cells *are* in development. The key for them is not that they're very efficient (they tend to be very inefficient), but that they should be very cheap to produce (no silicon refining needed). Of course, a few companies (such as Nanosolar) are working on commercializing high-efficiency dye-based cells. I read nanosolar's main patent at one point; basically, the efficiency problem with most organic solar cells is an uneven distribution of electron donors and receivers that leads to most of the electrons being wasted. In Nanosolar's case, they build a crystalline scaffolding that the dye gets embedded into at regular intervals, then dissolve the scaffolding.
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To clarify, it's not the electron itself that traverses the chlorophyll molecule(s), but the energy of the electron (somewhat analogous to kinetic energy transfer in Newton's Cradle). See also (Resonance Energy Transfer )