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    Thread: Photosynthesis and Quantum Mechanics

    1. #1
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      Photosynthesis and Quantum Mechanics

      I have read about it before somewhere - that photosynthesis makes use of quantum-phenomena - and now I found the following:

      Algae can switch quantum coherence on and off | KurzweilAI

      "Quantum coherence could allow the energy to test every possible pathway simultaneously before traveling via the quickest route"

      Algae that survive in very low levels of light and are able to switch quantum coherence on and off have been discovered by a UNSW-led team of researchers.

      The function for this effect, which occurs during photosynthesis, remains a mystery. But working out its role in a living organism could lead to technological advances, such as better organic solar cells and quantum-based electronic devices.

      The research is published in the journal Proceedings of the National Academy of Sciences.

      Quantum biology

      The research is part of an emerging field called quantum biology, in which evidence is growing that quantum phenomena are operating in nature, not just the laboratory, and may even account for how birds can navigate using the earth’s magnetic field.

      “Most cryptophytes have a light-harvesting system where quantum coherence is present,” says senior author, Professor Paul Curmi, of the UNSW School of Physics. “But we have found a class of cryptophytes where it is switched off because of a genetic mutation that alters the shape of a light-harvesting protein.

      “This is a very exciting find. It means we will be able to uncover the role of quantum coherence in photosynthesis by comparing organisms with the two different types of proteins.”

      A system that is coherent — with all quantum waves in step with each other — can exist in many different states simultaneously, an effect known as superposition. This phenomenon is usually only observed under tightly controlled laboratory conditions.

      The same effect has been found in green sulphur bacteria that also survive in very low light levels. “The assumption is that this could increase the efficiency of photosynthesis, allowing the algae and bacteria to exist on almost no light,” says Curmi.

      A powerful genetic switch to control coherence

      “Once a light-harvesting protein has captured sunlight, it needs to get that trapped energy to the reaction center in the cell as quickly as possible, where the energy is converted into chemical energy for the organism.

      “Quantum coherence would allow the energy to test every possible pathway simultaneously before traveling via the quickest route.”

      This is similar to how quantum computers (QC) are able to solve the classic “traveling salesman” problem to find the the shortest possible route among cities visited. Curiously, bees are also able to solve this kind of problem. Could bees also be using quantum coherence?

      “No,” says Curmi. “There are many ways to solve the traveling salesman problem. QC is only one proposal. Bees, slime molds and other systems do it by having vast numbers of individuals searching for a solution simultaneously and communicating their finding to each other. In this way, they collectively solve the problem via consensus. They have no need for any quantum mechanical effects.”

      In the new study, the team used x-ray crystallography to work out the crystal structure of the light-harvesting complexes from three different species of cryptophytes.

      They found that in two species a genetic mutation has led to the insertion of an extra amino acid that changes the structure of the protein complex, disrupting coherence.

      “This shows cryptophytes have evolved an elegant but powerful genetic switch to control coherence and change the mechanisms used for light harvesting,” says Curmi.

      Practical uses

      “This is the first time anyone has seen a protein system where through evolution a structural change has occurred that simultaneously changes the structure of the protein and switches the QC properties of the system,” Curmi told KurzweilAI in an email.

      “Our discovery will open the way to determining whether photosynthetic algae use quantum coherent (QC) effects in light harvesting. Our goal now is to determine the biological consequences of a photosynthetic organism possessing a light harvesting system which has QC versus one that does not. Second, we want to learn whether a single organism can switch QC on and off and under what conditions it does so.

      “If it turns out that QC is biologically important to light harvesting, then it may be utilized in synthetic light harvesting systems such as in photocells, photovoltaics, etc.”

      But don’t expect this to show up as a Best Buy gadget anytime soon. “This is basic research. We are a long way from understanding the system and utilizing the knowledge for applications.”

      Scientists from the University of Toronto, the University of Padua, the University of British Columbia, the University of Cologne and Macquarie University were also involved in the study.

      Abstract of Proceedings of the National Academy of Sciences paper:

      Observation of coherent oscillations in the 2D electronic spectra (2D ES) of photosynthetic proteins has led researchers to ask whether nontrivial quantum phenomena are biologically significant. Coherent oscillations have been reported for the soluble light-harvesting phycobiliprotein (PBP) antenna isolated from cryptophyte algae. To probe the link between spectral properties and protein structure, we determined crystal structures of three PBP light-harvesting complexes isolated from different species. Each PBP is a dimer of αβ subunits in which the structure of the αβ monomer is conserved. However, we discovered two dramatically distinct quaternary conformations, one of which is specific to the genus Hemiselmis. Because of steric effects emerging from the insertion of a single amino acid, the two αβ monomers are rotated by ∼73° to an “open” configuration in contrast to the “closed” configuration of other cryptophyte PBPs. This structural change is significant for the light-harvesting function because it disrupts the strong excitonic coupling between two central chromophores in the closed form. The 2D ES show marked cross-peak oscillations assigned to electronic and vibrational coherences in the closed-form PC645. However, such features appear to be reduced, or perhaps absent, in the open structures. Thus cryptophytes have evolved a structural switch controlled by an amino acid insertion to modulate excitonic interactions and therefore the mechanisms used for light harvesting.

      references:
      Stephen J. Harrop et al., Single-residue insertion switches the quaternary structure and exciton states of cryptophyte light-harvesting proteins, Proceedings of the National Academy of Sciences, 2014, DOI: 10.1073/pnas.1402538111



      Scanning electron microscope image of cryptophytes (credit: CSIRO)




      Hm - so maybe Roger Penrose might be worth a second look?
      Consciousness is not photosynthesis - but anyway...

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      perhaps it's the switch to consciousness lol. Just think of the double slit experiment and how the observer effect makes the wave function collapse. This is actually quite similar in a way except here there is a genetic change and an addition of an amino acid which collapses the wave function.
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      I have to admit - I am completely clueless here - but it sounds extremely fascinating!
      Maybe we get some more feedback - or I find some other articles on this phenomenon - photosynthesis and how the energy harvested from the sun gets fed into the "executive organelles" per routes found with the help of quantum entanglement - or whatever would be correct to say here...

      And Emeralda the photosynthetic sea slug might be a quantum-critter as well then, I guess!
      http://www.dreamviews.com/science-ma...ld-elysia.html

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      Just a second, let me just brush up my knowledge of QM terms for a little bit. (as much as my intelligence allows ofcourse )
      Last edited by Dthoughts; 07-04-2014 at 01:21 AM.
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      Quote Originally Posted by Curmi
      The same effect has been found in green sulphur bacteria that also survive in very low light levels. “The assumption is that this could increase the efficiency of photosynthesis, allowing the algae and bacteria to exist on almost no light,” says Curmi.
      In contrast to what the scientist is saying I had thought that disrupting coherence would need some type of information to be inbedded in the cell protein that would allow it to reach the "executive organelle" in the most opimized route as opposed to the brute force approach with normal coherence. One would think that a genetic mutation is actually a progressive switch. But then again a random adaptation resulting from having more light to work with might be a more conventional evolutionary perspective. But.. Considering that I don't know very much either I think i'll just wait and let the scientist come up with news when they compare the two different mechanisms. Hehe.
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      "Hehe" indeed - not sure, if I understand your thinking here, Dthoughts - but I'm happy about the fact that you do said thinking!


      Plant cells with visible chloroplasts (from a moss, Plagiomnium affine) Credit: Wikipedia

      I've been nosing around a bit - and this seems to be a good article to start out with: Quantum mechanics boosts photosynthesis - physicsworld.com

      Physicists in Canada and Australia have shown that nature exploits quantum mechanics to make photosynthesis more efficient. By probing light-harvesting proteins within algae using laser beams, the researchers found that quantum coherence links molecules within these proteins. They say that these links improve the transfer of energy in the production of life-supporting sugars.

      Photosynthesis involves using sunlight to convert carbon dioxide into chemical energy containing sugars. However, the protein complexes that carry out the necessary reactions do not absorb sunlight themselves. Instead, they rely on electrons being excited within pigment molecules housed in other proteins, with typically hundreds of pigment molecules supplying energy to an individual reaction centre. One reason for supplying energy indirectly in this way is that some photosynthetic reactions need the energy from several electron excitations in quick succession, something that would otherwise not be possible if light levels were low.


      The transfer of energy from light-harvesting proteins to reaction centres is a highly efficient process. Scientists already know, for example, that the various pigments inside each protein are just the right distance from one another – close enough to enable fast energy transfer, but not so close that the molecular orbitals of the pigments overlap and quench their excited states. It is also known that the arrangement of the proteins allows the energy to be sent via many different routes.

      Now, however, Elisabetta Collini of the University of Toronto and colleagues are proposing that the energy-transfer process is made even more efficient via quantum coherence. They suggest that the pigment molecules do not act entirely on their own, but interact so that when one molecule is excited by a photon from the Sun, it can to some extent share that excitation quantum mechanically with other pigment molecules. This superposition of excited states will then oscillate, shifting the excitations from one set of molecules to another and then back again on a very short timescale, allowing energy to be transferred to the reaction centres before it is released as light or heat.

      In tune

      Collini's team studied this phenomenon in two kinds of light-harvesting protein found in cryptophyte algae, taking advantage of the fact that the main pigment in these proteins, known as bilin, can be tuned to absorb light across a wide range of frequencies. The researchers first exposed the proteins to a pair of short-duration laser pulses, exciting the constituent pigment molecules, before stimulating emission from these excited states by sending in a third pulse shortly afterwards.

      What the team was looking for were emission frequencies that did not match the excitation frequency, because these would indicate the existence of a superposition of different states. This they did by detecting the quantum-mechanical equivalent of beats, the cyclical peak in volume produced when two sound waves of different frequency interfere with one another. The fact that they did indeed detect such beats is evidence, they say, that the algae takes advantage of quantum coherence.

      The researchers also found that the oscillations of this coherent superposition lasted for over 400 femtoseconds (4 × 10–13 s), which was much longer than expected. They had thought the oscillations would last for no more than 100 fs, because this was the timescale over which they thought interference from the surrounding protein and water molecules would swamp or "decohere" the delicate quantum superposition state. "[We] never anticipated such remarkable effects," says Collini's colleague, Gregory Scholes of the University of Toronto, also because bilin molecules interact more weakly with one another than do other photosynthetic pigments.

      Playing a role

      Such oscillating coherence has been observed before when Graham Fleming of the University of Berkeley, California, and colleagues studied the light-harvesting proteins of green sulphur bacteria in 2007. That experiment, however, was carried out at a mere 77 Kelvin, significantly reducing environmental interference and therefore minimizing the problem of decoherence. The latest work, in contrast, was carried out at room temperature, suggesting that quantum coherence really does play a role in photosynthesis.

      Indeed, Paul Davies, director of the BEYOND Center for Fundamental Concepts in Science at Arizona State University in the US, believes that quantum mechanics might be deployed more widely in the natural world. "My feeling is that nature has had billions of years to evolve to the 'quantum edge' and will exploit quantum efficiencies where they exist, even if the payoff is relatively small," he says.
      "I suspect that many biological nanostructures can be understood fully only by reference to quantum coherence, tunnelling, entanglement and other non-trivial processes. The challenge is to identify such quantum goings-on amid the complex and noisy environment of the cell."

      About the author
      Edwin Cartlidge is a science writer based in Rome

      Some more technical stuff from here: Quantum mechanics explains efficiency of photosynthesis

      "Energy transfer in light-harvesting macromolecules is assisted by specific vibrational motions of the chromophores," said Alexanda Olaya-Castro (UCL Physics & Astronomy), supervisor and co-author of the research.
      Molecular vibrations are periodic motions of the atoms in a molecule, like the motion of a mass attached to a spring. When the energy of a collective vibration of two chromphores matches the energy difference between the electronic transitions of these chromophores a resonance occurs and efficient energy exchange between electronic and vibrational degrees of freedom takes place.

      Providing that the energy associated to the vibration is higher than the temperature scale, only a discrete unit or quantum of energy is exchanged.
      Consequently, as energy is transferred from one chromophore to the other, the collective vibration displays properties that have no classical counterpart.
      The UCL team found the unambiguous signature of non-classicality is given by a negative joint probability of finding the chromophores with certain relative positions and momenta. In classical physics, probability distributions are always positive.

      "The negative values in these probability distributions are a manifestation of a truly quantum feature, that is, the coherent exchange of a single quantum of energy," explained Edward O'Reilly (UCL Physics & Astronomy), first author of the study. "When this happens electronic and vibrational degrees of freedom are jointly and transiently in a superposition of quantum states, a feature that can never be predicted with classical physics."

      Other biomolecular processes such as the transfer of electrons within macromolecules (like in reaction centres in photosynthetic systems), the structural change of a chromophore upon absorption of photons (like in vision processes) or the recognition of a molecule by another (as in olfaction processes), are influenced by specific vibrational motions. The results of this research therefore suggest that a closer examination of the vibrational dynamics involved in these processes could provide other biological prototypes exploiting truly non-classical phenomena.

      Now I only needed somebody (Xei?) to come along and explain some of it from the second article a bit more clearly:

      "Negative values in these probability distributions..."
      Does this mean, what is being observed in terms of position and momentum of atoms is not probable/possible to come about under classical physics - I am not sure I understand this. Same with the degrees of freedom - is it so, that the mere probabilities resonate with each other? Or is it energetic states?

      What this whole "finding the best way" phenomenon brings to my mind now is refraction of light for example through water.
      To phrase it anthropomorphically - how does light know which route to take?
      It seems to "find out" the fastest route only by already taking that path.
      How does this effect come to pass? I used to know about it...
      QM as well?

    7. #7
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      Hey, I took a shot at understanding the articles and here's my rudimentary understanding of what is explained in the above. I am genuinely worried that I might offend you or anyone else for that matter so I hope to make clear that I don't mean to sound like I am lecturing instead of wording my own (possibly faulty) take on it. This all probably sounds way too serious but I just wanted to let that be clear

      "Negative values in these probability distributions..."

      I don't know how they use the term in a mathematical sense but I am positively certain that you understood correctly and they meant that it is just not probable in any classical system to have a collective vibration of two chromophores vibrate in a relatively synchronistic motion.

      Further elaboration found here
      Quote Originally Posted by Nature
      Non-classicality of initially thermalized vibrations is induced via coherent exciton–vibration interactions and is unambiguously indicated by negativities in the phase–space quasi-probability distribution of the effective collective mode coupled to the electronic dynamics.
      I think this makes it very clear that they meant that it is (simply put) impossible to ascribe the dynamics of classical electron transfer as solely responsible for producing "thermalized vibrations" as they named it.

      And ofcourse "vibration-assisted energy transfer " is basically a transference of energy from one form into another.

      Call me dense, but I think vibrational transfer of energy is akin to pushing a bunch of dominoes in a particular direction. One photon comes in and excites a molecule's atoms. It is stated in the article you linked that molecular orbitals of electrons are at just the right distance to each other so as not to interfere. I can picture an incoming photon to increase the size of a cholorophyl's molecular orbit. Which results in a push that excites it's neighbours "molecular orbit" etc. producing a domino effect. Until eventually it agitates the executive organelle and an electron is forcefully released which was originally in peaceful orbit around that organelle.

      jpegreaction.jpg

      Either way, this picture explains what is generally going on and helps a lot in understanding what they meant.

      To further investigate this phenomenon (and my theory which is basically about magnetic fields) I may have to look into the mechanism in which the "Executive organelles" transfer electrons as depicted in this picture. Which is more of a classical look at photosynthesis. Which I know nothing about, I haven't had that class about photosynthesis in school just yet.

      Note that the electron that ends up being used in quantum photosynthesis is different from the one that is used in a classical photosynthesis as do these Algea. I still don't understand why these Algea would evolve a protein that disrupts coherence if beforehand they had an essentially more effective system already in place. I think it might be helpful in our understand of this evolutionary phenomenon that different kinds of electrons are being transfered when utilizing different kinds of photosyntheseses.
      Last edited by Dthoughts; 07-04-2014 at 09:07 PM.
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      Quote Originally Posted by Dthoughts View Post
      Hey, I took a shot at understanding the articles and here's my rudimentary understanding of what is explained in the above. I am genuinely worried that I might offend you or anyone else for that matter so I hope to make clear that I don't mean to sound like I am lecturing instead of wording my own (possibly faulty) take on it. This all probably sounds way too serious but I just wanted to let that be clear

      "Negative values in these probability distributions..."

      I don't know how they use the term in a mathematical sense but I am positively certain that you understood correctly and they meant that it is just not probable in any classical system to have a collective vibration of two chromophores vibrate in a relatively synchronistic motion.

      Further elaboration found here

      I think this makes it very clear that they meant that it is (simply put) impossible to ascribe the dynamics of classical electron transfer as solely responsible for producing "thermalized vibrations" as they named it.

      And of course "vibration-assisted energy transfer " is basically a transference of energy from one form into another.

      Call me dense, but I think vibrational transfer of energy is akin to pushing a bunch of dominoes in a particular direction. One photon comes in and excites a molecule's atoms. It is stated in the article you linked that molecular orbitals of electrons are at just the right distance to each other so as not to interfere. I can picture an incoming photon to increase the size of a cholorophyl's molecular orbit. Which results in a push that excites it's neighbours "molecular orbit" etc. producing a domino effect. Until eventually it agitates the executive organelle and an electron is forcefully released which was originally in peaceful orbit around that organelle.

      jpegreaction.jpg

      Either way, this picture explains what is generally going on and helps a lot in understanding what they meant.

      To further investigate this phenomenon (and my theory which is basically about magnetic fields) I may have to look into the mechanism in which the "Executive organelles" transfer electrons as depicted in this picture. Which is more of a classical look at photosynthesis. Which I know nothing about, I haven't had that class about photosynthesis in school just yet.
      Wow!!
      Great post - thank you - I guess now I understand it - at least better than before!
      And my goodness - you are still in school!
      Another wow for you being so beautifully knowledge-thirsty and enthusiastic and clever to boot!

      Quote Originally Posted by Dthoughts View Post
      Note that the electron that ends up being used in quantum photosynthesis is different from the one that is used in a classical photosynthesis as do these Algea. I still don't understand why these Algea would evolve a protein that disrupts coherence if beforehand they had an essentially more effective system already in place. I think it might be helpful in our understand of this evolutionary phenomenon that different kinds of electrons are being transfered when utilizing different kinds of photosyntheseses.
      Do you mean, the algae use another protein, with a different gene-sequence? I wouldn't know, what you mean with different electron here...?
      Otherwise good question - why would they? When I read this:

      “Most cryptophytes have a light-harvesting system where quantum coherence is present,” says senior author, Professor Paul Curmi, of the UNSW School of Physics. “But we have found a class of cryptophytes where it is switched off because of a genetic mutation that alters the shape of a light-harvesting protein.
      It rather sounds to me, as if they found a cryptophyte, which doesn't switch this on and off itself as it needs it - but one that has a genetic code, in which this protein's quantum capabilities are always switched off. Why? Well - maybe because of something completely different, which doesn't have to do with photosynthesis - some advantage coming with it per another mechanism. Or it's a "mistake" maybe - but why would it have stayed that way, if it was only bringing disadvantage?
      I guess, what they find great, is that they can study the proteins in comparison and learn new things about how biochemistry and quantum physics are entangled this way...

      Hm, hm - yeah - but the interesting question here is really an evolutionary one as well, with these little critters.

    9. #9
      Xei
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      Quantum mechanics has a reputation as a kind of crazy theory which only turns up in very special situations, but it's not. Everything about the behaviour of particles, including atoms and all of chemistry - the fact our world is stable at all rather than collapsing into a chaotic mush - is a direct expression of quantum mechanics and inexplicable without it. Photosynthesis involves tiny bespoke biochemical structures involved in capturing single photons and turning them into the potential energy of single electrons in a novel way, so in this sense it's inevitable that they'd require quantum effects to sufficiently explain.

      I just thought that was a point worth making - the quantum part isn't news. But of course, that wouldn't detract from the news of specific and surprisingly exotic quantum effects - however, on these matters I am entirely ignorant, having only ever covered the basics, and so can't give any useful opinions.

      With respects to your question on negative probabilities: they're not well-known in mathematical study, but basically from skimming this page,

      Negative probability - Wikipedia, the free encyclopedia,

      I get the impression that they just seem to feature in quantum mechanics as a useful calculation tool. They're useful is all - if you use negative values, you end up with results which accurately model the real world. The worrying-sounding question of whether or not negative probabilities "actually exist" is an entirely meaningless discussion. Nor do any worrying collisions between such weird entities and the "real world" take place, because by the time you make a prediction, all of the probabilities are positive - if you got a negative probability of observing a certain event, then there would be a problem. But that's not how it works out. I can actually draw on my limited experience of quantum mechanics here because there's something else in QM which seems to me entirely analogous to this: namely that the quantum wavefunction (which basically assigns a probability to each location in space) actually uses complex numbers, because this correctly describes how the waves change and interact. But when you come to determine the probability of an actual measurement, you take the "absolute value" of the complex number, which ends up giving you a number between 0 and 1. So again: just a nice way of modelling stuff, and one which doesn't somehow "materialise" in the final observation. In the context of this conversation, then, you can basically interpret them as saying, "when we take various measurements of a phenomenon and plug them into a certain formula [which happens to have other useful applications], we get positive numbers for classical systems but sometimes negative numbers for quantum systems, and thus the fact we got negative numbers here means that there's quantum stuff going on".

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      Quote Originally Posted by Xei
      In the context of this conversation, then, you can basically interpret them as saying, "when we take various measurements of a phenomenon and plug them into a certain formula [which happens to have other useful applications], we get positive numbers for classical systems but sometimes negative numbers for quantum systems, and thus the fact we got negative numbers here means that there's quantum stuff going on".
      Perfect - thank you! Sorry for plucking your post apart and rearranging. This helped me grasp it and enjoy it!

      Quote Originally Posted by Xei View Post
      Quantum mechanics has a reputation as a kind of crazy theory which only turns up in very special situations, but it's not. Everything about the behaviour of particles, including atoms and all of chemistry - the fact our world is stable at all rather than collapsing into a chaotic mush - is a direct expression of quantum mechanics and inexplicable without it. Photosynthesis involves tiny bespoke biochemical structures involved in capturing single photons and turning them into the potential energy of single electrons in a novel way, so in this sense it's inevitable that they'd require quantum effects to sufficiently explain.
      Yes - one should think that. Interesting new things to discover all over the place, I'm sure!

      Quote Originally Posted by Xei
      With respects to your question on negative probabilities: they're not well-known in mathematical study, but basically from skimming this page,

      Negative probability - Wikipedia, the free encyclopedia,
      Ah - thank you! Interesting article!
      I thought, it might be something I had missed out on, something ubiquitous in higher mathematics, and I didn't expect typing it in Wikipedia would bring me somewhere understandable.
      So it's quantum-mathematics! But not only - they have great and easily followable examples:

      Quote Originally Posted by Wikipedia
      The probability of the outcome of an experiment is never negative, but quasiprobability distributions can be defined that allow a negative probability for some events. These distributions may apply to unobservable events or conditional probabilities.

      In 1942, Paul Dirac wrote a paper "The Physical Interpretation of Quantum Mechanics" where he introduced the concept of negative energies and negative probabilities:

      "Negative energies and probabilities should not be considered as nonsense. They are well-defined concepts mathematically, like a negative of money."
      The idea of negative probabilities later received increased attention in physics and particularly in quantum mechanics. Richard Feynman argued[2] that no one objects to using negative numbers in calculations: although "minus three apples" is not a valid concept in real life, negative money is valid. Similarly he argued how negative probabilities as well as probabilities above unity possibly could be useful in probability calculations.

      Mark Burgin gives another example:

      "Let us consider the situation when an attentive person A with the high knowledge of English writes some text T. We may ask what the probability is for the word “texxt” or “wrod” to appear in his text T. Conventional probability theory gives 0 as the answer. However, we all know that there are usually misprints. So, due to such a misprint this word may appear but then it would be corrected. In terms of extended probability, a negative value (say, -0.1) of the probability for the word “texxt” to appear in his text T means that this word may appear due to a misprint but then it’ll be corrected and will not be present in the text T."

      —Mark Burgin, Burgin, Mark (2010). "Interpretations of Negative Probabilities"


      Quote Originally Posted by Xei View Post
      I get the impression that they just seem to feature in quantum mechanics as a useful calculation tool. They're useful is all - if you use negative values, you end up with results which accurately model the real world. The worrying-sounding question of whether or not negative probabilities "actually exist" is an entirely meaningless discussion. Nor do any worrying collisions between such weird entities and the "real world" take place, because by the time you make a prediction, all of the probabilities are positive - if you got a negative probability of observing a certain event, then there would be a problem. But that's not how it works out.
      This very much reminds me of the something from nothing debate. Quantum foam and negative energy, as far as I remember, but I guess negative probabilities belong there as well. What Lawrence Krauss likes saying, is that our brains might be unable to deal with quantum mechanics "properly". Having a sense of grasping the basic principles "directly" I mean. Maybe that's why "meaningless questions" tend to bother us so much - because of how we are wired? Like what was there before time came into existence?

      Quote Originally Posted by Xei
      I can actually draw on my limited experience of quantum mechanics here because there's something else in QM which seems to me entirely analogous to this: namely that the quantum wavefunction (which basically assigns a probability to each location in space) actually uses complex numbers, because this correctly describes how the waves change and interact. But when you come to determine the probability of an actual measurement, you take the "absolute value" of the complex number, which ends up giving you a number between 0 and 1.
      Ah - imaginary numbers - just give reality one more dimension, don't care for apples but solve real world problems! We had them in school and I instantly liked this approach.

      Quote Originally Posted by Xei
      So again: just a nice way of modelling stuff, and one which doesn't somehow "materialise" in the final observation.
      Just probabilities might not "manifest" or directly "interfere" with reality in any useful sense of the words. But something "feeling quite like it", negative and positive energy inherent in nothing, might be how the universe materialised out of said nothing, the absence of something - if I understand the above mentioned cosmologist correctly..?
      Mind blown.

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