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Quantum Coherence Found Fueling Photosynthesis 135

Posted by samzenpus
from the spooky-energy dept.
Gaygirlie writes "Ars Technica has posted an interesting article about new findings regarding quantum physics and photosynthesis. Their excerpt for the article: 'Physicists have found the strongest evidence yet of quantum effects fueling photosynthesis. Multiple experiments in recent years have suggested as much, but it has been hard to be sure. Quantum effects were clearly present in the light-harvesting antenna proteins of plant cells, but their precise role in processing incoming photons remained unclear.' Here's a little background info for those unaware of what coherence and quantum coherence are."
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Quantum Coherence Found Fueling Photosynthesis

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  • by LucidBeast (601749) on Wednesday December 07, 2011 @04:35PM (#38294934)
    helped me, yet again, realize how little I understand quantum physics.
    • Re: (Score:3, Interesting)

      by Anonymous Coward

      "If you think you understand quantum physics, then clearly you don't."

      -Paraphrased Richard Feynman quote

      • by mcgrew (92797) * on Wednesday December 07, 2011 @05:38PM (#38295688) Homepage Journal

        "If you think you understand quantum physics, then clearly you don't." -Paraphrased Richard Feynman quote

        I don't think I understand it, so does that mean I do?

        As to TFA, it led me to think that this could lead to more powerful and cheaper solar cells. This is an exciting time to be alive. I can see a future without those damned ugly poles and wires in the alley behind my house, with a beautiful solar paneled roof and an even more beautiful lack of an electric bill. Who knows watt will come of investigation into quantum mechanics?

        (yes, that "typo" was a deliberate pun)

        • by postbigbang (761081) on Wednesday December 07, 2011 @05:43PM (#38295764)

          Your solar panels will be green, and smell vaguely like broccoli, with little graphene wires. You may have to water them.

        • The real future is when we dyson sphere [wikipedia.org] the sun and teleport the energy directly to devices that need it using quantum entanglement. Near-limitless wireless energy anywhere in the universe!



          Spoilers: It may be awhile.
          • by FooAtWFU (699187)

            While I know enough to know that I don't really understand squat quantum physics, I'm pretty confident in saying that quantum teleportation is not actually an energy transport mechanism. It can't even teleport classical information.

            • I don't think we've proven any of that for sure yet. Absolutely what I'm talking about is beyond theoretical, but given infinite scientific advancement who is to say what is or is not physically possible? ^_^

              I never mentioned quantum teleportation. Just some process whereby using quantum mechanical science we might achieve energy transfer. I think I read a paper on the concept awhile ago... anyways.
              • You did claim it would come through quantum entanglement (what some people call quantum teleportation). It is impossible to transmit even classical information through quantum entanglement, and that was proven for sure already.

                • It is impossible to transmit even classical information through quantum entanglement, and that was proven for sure already.

                  When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong. -Arthur C. Clarke

                  Who would figure a few years ago that flash storage by quantum tunneling would be possible? We only just considered quantum mechanics a possibility in the last century. By current understanding yeah, but what if we find a whole new realm of science on the sub-quantum level?

                  • By current understanding yeah, but what if we find a whole new realm of science on the sub-quantum level?

                    I'm not convinced it's a good idea to stake the future of humanity on what we might discover.

                    "What if we discover perpetual motion and warp drive?? Wouldn't that be great!!" Yep.

                    • A warp drive would be great. This all started in response to,

                      This is an exciting time to be alive. I can see a future without those damned ugly poles and wires in the alley behind my house, with a beautiful solar paneled roof and an even more beautiful lack of an electric bill. Who knows watt will come of investigation into quantum mechanics?

                      This isn't a feasibility study on technology to roll out next year. I was quite facetious from the very beginning.

                      Why so serious? Just talking. Nobody's staking anything on anything...

                  • That phrase makes sense when talking about more general things, but not well defined concepts of a theory. Quantum entanglement is a mathematical construction, and it was already proved that it doesn't transmit information. If Nature doesn't work the way our theories say it works* and teleportation is possible, it will be due to another phenomenum that can't be modeled as quantum entanglement.

                    By the way, quantum tunneling doesn't lead to flash memory either. You should check how it is made, it is quite more

                    • By the way, quantum tunneling doesn't lead to flash memory either. You should check how it is made, it is quite more mundane than that.

                      From Flash Memory [wikipedia.org]
                      To erase a NOR flash cell (resetting it to the "1" state), a large voltage of the opposite polarity is applied between the CG and source, pulling the electrons off the FG through quantum tunneling. Modern NOR flash memory chips are divided into erase segments (often called blocks or sectors). The erase operation can only be performed on a block-wise basis; all the cells in an erase segment must be erased together. Programming of NOR cells, however, can generally be performed one byte or w

              • You could always use mirrors. Just aim the sun's output to a solar collector in your yard. should be fine.
                • I'm talking about how an intergalactic civilization would manage resources. When resource demands are so high that dyson sphering the sun is actually practical, you're going to be dealing with extreme costs to transport that energy in some fuel form (dark matter, lots of energy cells, who knows) around space so that you can use it; instead if you could somehow use quantum technology to teleport that energy the savings would be enormous. By the time we need it, we'll probably figure out a way.
        • I can see a future without those damned ugly poles and wires in the alley behind my house, with a beautiful solar paneled roof and an even more beautiful lack of an electric bill

          Does more sunlight energy hit your roof than you consume?

      • by pclminion (145572) on Wednesday December 07, 2011 @05:53PM (#38295914)

        Feynman was talking about understanding the "why" sort of questions of quantum mechanics. It is possible to completely understand quantum mechanics as it currently exists. After all, humans created it. Feynman himself was responsible, along with a handful of others, for buttoning up QED into the most complete and perfect physical theory we have as of yet. When he said "nobody understands this stuff," he meant that nobody understands WHY the world is this way. We understand perfectly well how to use the rules to predict the answer.

        Neither was he referring to the various "strange" things that sometimes occur at quantum scales. There is nothing spooky in quantum mechanics, it's all sitting right there in the equations. Equations which were essentially guessed at by men with intuitions the size of Mount Everest, and these guesses were then proven to be correct at ever increasing levels of accuracy. So obviously people are "getting it" on some level. But the deeper sort of "why" questions Feynman relegated to philosophers, and he ridiculed those who wasted their time asking them.

        • Re: (Score:3, Insightful)

          by nessus42 (230320)

          There is nothing spooky in quantum mechanics

          Sure there is. Or there very well might be. Nobody understands the Copenhagen Interpretation of quantum mechanics because it is ill-defined. If on the other hand, the correct interpretation of quantum mechanics is the Many Worlds/Everett Interpretation, then the entire universe is in an incredibly complex macroscopic superposition of states all the the time, amounting to a staggeringly large number parallel worlds. Most people will claim that this is "spooky". In

        • by tehcyder (746570)
          If you don't find the many worlds hypothesis, or quantum entanglement somewhat more than spooky, you must have no imagination. Simply saying that because the equations work there's nothing else to think about is somewhat trite.
    • by Eternauta3k (680157) on Wednesday December 07, 2011 @05:07PM (#38295278) Homepage Journal
      I'm at that awful stage where I laugh at this article's analogies, yet can't really understand the paper.
    • by Culture20 (968837) on Wednesday December 07, 2011 @05:08PM (#38295294)
      Are you saying they weren't coherent?
    • It sure doesn't help that he just linked to wikipedia on coherence and quantum coherence.
      At that point, why not just let me google that for you [lmgtfy.com] ? Does this really need inclusion? Its almost insulting.

      Seriously guys if somebody doesn't understand quantum physics reading the wiki page isn't going to do it.
      • by FrootLoops (1817694) on Wednesday December 07, 2011 @08:20PM (#38297648)

        Seriously guys if somebody doesn't understand quantum physics reading the wiki page isn't going to do it.

        More than that, the first paragraph of the linked explanation is misleading, and the rest essentially requires an understanding of quite a bit of quantum mechanics to have a chance of following it. I have difficulty imagining somehow who actually understood the concepts involved linking such a poor explanation.

        Quantum coherence has to do with multiple particles. If most of the particles are in roughly the same (quantum) state, the system is called coherent. Otherwise, it is not coherent. To give an (oversimplified) example, take a bunch of electrons. Through a clever experiment, we may measure an individual electron's "spin", and the result will either be "up" or "down"--an understanding of spin is immaterial here; feel free to replace "spin" with "mood" and "up"/"down" with "happy"/"sad" if it scares you. The unintuitive part of quantum mechanics is that even if we performed the experiment twice with two indistinguishable electrons, our experiment may well come out differently. The crucial thing, though, is that each outcome has a fixed probability of occurring. Suppose, then, that we've prepared 100 electrons in such a way that if we perform our spin experiment, 30% of the time the electron will have spin up, and 70% of the time it will have spin down. An electron's quantum state for this experiment is (sweeping wavefunctions under the rug...) given by the probability of each outcome. Each of our 100 electrons has the same quantum state as the others, so the system is called (perfectly) coherent. If, however, we prepared 50 of the electrons to come out with the above probabilities and the remaining 50 electrons to come out with 100% spin up, the system is not coherent.

        (Disclaimer: I am not a physicist, but rather a mathematician with some interest in quantum physics. Please feel free to correct or supplement the above.)

        • by harryjohnston (1118069) <harry.maurice.johnston@gmail.com> on Wednesday December 07, 2011 @09:59PM (#38298520) Homepage

          No, quantum coherence is not about the electrons all having the same quantum state as one another; it's about the system as a whole having a single quantum state.

          An example of a coherent system would be one in which the electrons all have the same spin; say a 50% chance that they are all up and a 50% chance that they are all down, but zero chance that some are up and some are down. Another example would be a 50% chance that the odd-numbered electrons are up and the even-numbered onees down, a 50% chance they're the other way around.

          • I have difficulty making "it's about the system as a whole having a single quantum state" rigorous. Could you elaborate?
            • Probably not without a better idea of your existing knowledge, but I'll have a go.

              Consider a simple point particle in one dimension. The wavefunction for the system is psi(x) where x represents the one-dimensional position. If you have two point particles, and they are coherent, the wavefunction is psi(x,y) where x and y represent the positions of the two particles. (For simplicity I'm assuming the two particles are distinguishable.)

              Any particular choice of wavefunction psi(x,y) is a possible quantum sta

              • I re-read my original comment with fresh eyes and discovered, to my surprise, that I didn't communicate what I meant to at the end very well at all. I must have been sleepy when I wrote it. I meant to say that, if we performed the experiment on a single randomly chosen electron, there was a 50% chance we had prepared it the first way, and a 50% chance in the second way. The resulting "system" would be incoherent, since it would be composed of two states.

                Now that I understand your objection, I imagine you're

    • Yes, I agree. I can't help but feel like I've been outsmarted by a plant.

  • Surprise? (Score:4, Insightful)

    by danhuby (759002) on Wednesday December 07, 2011 @04:35PM (#38294940) Homepage

    If quantum effects are real (as they demonstrably are), should it be a surprise that evolution made use of them?

    • Re:Surprise? (Score:4, Insightful)

      by iggymanz (596061) on Wednesday December 07, 2011 @04:40PM (#38294990)

      Anything emitting or absorbing light has to be modeled using quantum mechanics.

      • by Anonymous Coward

        Anything emitting or absorbing light has to be modeled using quantum mechanics.

        Isn't it already? Photoelectric effect is result of quantization of light. Einstein got a Nobel for that ;)

      • by atisss (1661313)

        Can be modeled using quantum mechanics.

        There are many models and they are overlaping, but there is no single theory that's absolutely true and explains everything. Even for just light.
        Theory is just how we think it works, and what we have learned to predict. It can be true, but that doesn't exclude other truths.

        • by iggymanz (596061)

          but with light there is fundamental known truth. It always is quantized, made of discrete chunks of energy. there is no alternative possible view to that. It is the first known quantum phenomenon. Anything involving light must have quantum (discrete) creation, transmission, absorption of energy.

          • That just reduces to the trivial argument that everything uses quantum effects because everything* derives ultimately from QM. It's equivocating compared to what the article is saying.

            Fire is a chemical effect that produces light. It's not a quantum effect, in that there's nothing to explain about fire using Quantum Mechanics that cannot be described using chemistry/thermodynamics (maybe a tiny bit of fluid dynamics). You do not need to include quantum mechanics in this mathematical model for the model t

            • But you can't explain chemistry without quantum mechanics.

            • by iggymanz (596061)

              fire is light and heat released by chemical reactions, which always involves changes in electron orbitals. Gravity might not be subject to quantization, neither might time. An experiment looking at phase relationships in photons from distant galaxy was made to look for quantization of time (Planck time unit), but none such was found (so inconclusive, maybe it's really small!)

      • by jovius (974690)

        Light, is a short of shade in the realm of electromagnetic frequencies, on which we all rest upon.

  • This *might* be related to my wife's PhD research from several years back. Proton Coupled Electron Transfer. She's in a seminar right now, but when she's back at her desk, I'll past this by her to see if it relates. I could be totally wrong, but I know physicists approach the same kinds of things using different terms and models than chemists. Either way, PCET is an interesting effect that also happens in photosynthesis:

    https://en.wikipedia.org/wiki/PCET [wikipedia.org]

  • "hard to be sure"

    Ha! Who would have guessed - uncertainty in quantum mechanics!

  • Photoelectric Effect (Score:5, Interesting)

    by cosm (1072588) <thecosm3&gmail,com> on Wednesday December 07, 2011 @04:59PM (#38295184)
    I've seen some comments stating that 'meh photoelectric effect nothing new to see here'. While it is true that emission/absorption is subject to quantum mechanics, specifically the photo-electric effect being governed by the work function hf = phi - eV, with hf = hc/lambda, phi being the work-function of the material, and eV being the 'escape velocity' of the electrons; the point being that energy emitted/absorbed must satisfy the above relationship, otherwise the photo-electric effect does not work.

    What I believe this study is saying is that 'antennae' structures can act as a single quantum mechanical unit (the coherence) so that the incoming insolar radiation has more paths for electron conduction, since the transfer of energy/conduction of electrons is limited to the quantization by the work function, i.e., charge quantization limits the specific wavelengths/frequencies/energies of incoming photons that the plant can use to harvest energy, so in effect the evolution of these 'antennae' structures over time allows for a coherent systems that can act as single particles, with the different permutations of antennas allowing for vastly more permutations of allowed incoming wavelengths to satisfy the Schrodinger eqn (probably not dirac since these are most likely not relativistic interactions, at least the effects are negligible).

    I deal more with relativity and QED/QCD, but that's my interpretation of the article.
    • by cosm (1072588)
      **I meant to type 'I deal more with relativity than I do QED/QCD', we haven't quite come to a point where the statement:
      IF (Relativity == True && QED-QCD == True) THEN { TheoriesMergedWithoutIssue = True;}

      Must of been my subconscious hoping for the yet to be completed reconciliation of the two :)
    • by slew (2918) on Wednesday December 07, 2011 @06:51PM (#38296592)

      Back in '07, this article was published...

      http://www.physics.gla.ac.uk/~dtngo/Article/Nature_446_782_2007.pdf [gla.ac.uk]

      As I understand this, in the classical photosynthesis model, energy transfer is sort of modeled like the incoming sunlight excites a population of light absorbing "antennea" pigments which transfer the energy to reaction centers where long term energy storage is initiated (e.g., the CO2->sugar conversion). If the energy transfer was "classically" photoelectric, you'd see a system where light excites a population of antenna of different pigments, which then re-emit the energy at a wavelength compatible with the photosynthesis.

      If this was true, you could potentially measure electric field and look for frequency of absorbtion and re-emission (they would look like 2 frequency peaks). However, if there were some sort of state coupling, you'd also see beat frequencies corresponding to the difference in energies between various pigments and the re-emission. That in itself is not that interesting, but the fact that when they sent in pulses, these frequencies corresponding to beat frequencies seems to persist longer than the expected coherence time which apparently suggests that coherence lasts long enough to transit all the way from the antenna/pigments to the location of energy conversion (in this case 660 femtoseconds).

      The next step is to hypothesize that you can use QM and treat the full system as essentially coherently absorbing light at with the exactly correct antenna/pigment and re-emitting it essentially lossless to the conversion point, rather than it absorbing a collection/population of antenna over a period of time (some of them efficiently, some of them less efficienty), and re-emitting the energy (the classical model). Of course this is a pretty big step and is not a constructive argument, but it is in line with observations about photosynthetic efficiency and there is now more measurements to back up the potential (QM/coherence) pathway which might be able to explain that efficiency..

  • by PortHaven (242123) on Wednesday December 07, 2011 @05:00PM (#38295194) Homepage

    The plants REALLY do have a chance against the Zombies. They can use their quantum energy blasters!!!!

  • by Warwick Allison (209388) on Wednesday December 07, 2011 @05:21PM (#38295442) Homepage

    Any evolved system will use all possible inputs to its fitness function, simply because there isn't any mechanism of focusing. Unlike human design, which is all about making known mechanisms work and all but those mechanism are ignored, and even actively avoided. When early researchers used solid-state electronics to make genetic algorithms, often the "solution" only worked on the specific hardware circuit it was learnt on (not supposedly identical copies), because it relied on otherwise-undefined race conditions in the silicon.

    So don't be surprised if quantum effects are also used by your brain cells ... and by your anal sphincter.

    • by timeOday (582209)
      Evolution uses everything? I've heard it said evolution never discovered the wheel.
      • Wheels are not inputs. The input is the roughness of the surface to be traveled over (and the lack of a naturally occurring road network is perhaps why animals don't use wheels).

      • by Tapewolf (1639955)

        Evolution uses everything? I've heard it said evolution never discovered the wheel.

        I have heard that ATP Synthase is actually implemented as a rotor... a micromotor spun by proton-motive force.

  • If you think our technology has traveled a long way so far, consider still how far ahead evolution is. Things like this amaze me.
  • spooky action at a distance " (at the heart of quantum coherence) had never been further than his salad bowl...

  • "Decoherence" (Score:5, Interesting)

    by Theovon (109752) on Wednesday December 07, 2011 @05:47PM (#38295836)

    The way people often describe quantum decoherence is that an "observation" occurs that "collapses the wave function" and causes a superposition to converge to a single classical state. But I really think that's a misleading explanation. For one thing, surely the same phenomena occurred long before there were any intelligent observers, and secondly, scientists have observed things in states of quantum superposition WITHOUT causing decoherence.

    The way think of it (as a total amateur in the area) is that rather than the wave function representing probabilities of states, it represents the degrees to which something is in all of those states. An "observation" is just like many other interactions with the environment that change those probabilities (or degrees of state).

    Then there's the question of why subatomic particles (and some larger things) can be in states of quantum superposition, while larger things cannot. Penrose had a suggestion here. It's gravity. The more massive you are, the less your superimposed states can diverge from one another. Even a planet is in a state of superposition, but all of those states overlap so much relative to the dimensions of the object that you cannot distinguish them.

    • I've got a much simpler, amateur explanation for Quantum Observation;

      Let's say the Photon is the size of a person, or an Electron the size of a Pig. "Observation" is like launching a Cow at that Human or Pig with a catapult, and then being totally surprised that you ruined the planned stroll of that person/pig.

      Before I take the alleged "Law of Quantum Physics" concerning observation seriously, we've got to find a way to OBSERVE with things that have less mass and energy than the particle or wave in question

    • The way people often describe quantum decoherence is that an "observation" occurs that "collapses the wave function" and causes a superposition to converge to a single classical state. But I really think that's a misleading explanation. For one thing, surely the same phenomena occurred long before there were any intelligent observers [...]

      I can't say if it's misleading or not (it might mislead someone...), but it doesn't sound misleading to me. But an important point is that most people nowadays accept that "observation" doesn't require (and has nothing to do with) an intelligent observer. A photon can "observe" a system just as well as a person.

      Also, there are many interpretations of quantum mechanics where the collapse of the wavefunction is not as fundamental as in Copenhagen. For example, here's an account of an extension of the Schr

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