Physicists See Quantum Effects in Photosynthesis

By Bill Andrews | May 21, 2018 10:26 am
(Credit: Shutterstock)

With photosynthesis, scientists show for the first time that there are quantum effects in living systems. This could lead to better solar panels, energy storage or even quantum computers.  (Credit: Shutterstock)

We all probably learned about photosynthesis, how plants turn sunlight into energy, in school. It might seem, therefore, that we figured out this bit of the world. But scientists are still learning new things about even the most basic stuff (see also the sun and moon), and photosynthesis is no different.

In particular, according to a study released Monday in Nature Chemistry, an international team of scientists showed that molecules involved in photosynthesis display quantum mechanical behavior. Even though we’d suspected as much before, this is the first time we’ve seen quantum effects in living systems. Not only will it help us better understand plants, sunlight and everything in between, but it could also mean cool new tech in the future.

The Quantum Conundrum

First, let’s back up. While photosynthesis may be taught in classrooms the world over, quantum mechanics is a bit less popular, in part because it’s so weird. Nobel Prize-winning quantum physicist Richard Feynman once said, “I think I can safely say that nobody understands quantum mechanics.” It’s so impenetrable to non-experts that the same metaphors come up whenever someone tries to explain it.

You might have heard of Schrödinger’s Cat, which is both alive and dead at the same time thanks to quantum weirdness — in particular, because electrons can be in two states at the same time. It’s only when we observe the system that the weirdness collapses and reality “picks” one state: the cat’s actually alive (or dead), the electron’s actually at this end of the room (or that end).

But quantum effects are typically limited to the very small, and only really observable in perfect, laboratory conditions. A living being, with its wet, messy systems, would be a tough place to find some quantum weirdness lurking — and yet we have.

Above is the photosynthetic complex of light-harvesting green sulfur bacteria. The green and yellow circles highlight the two molecules simultaneously excited. (Credit: Dr. Thomas la Cour Jansen/ University of Groningen)

Above is the photosynthetic complex of light-harvesting green sulfur bacteria. The green and yellow circles highlight the two molecules simultaneously excited. (Credit: Dr. Thomas la Cour Jansen/ University of Groningen)

Molecular Madness

Scientists zoomed in on the Fenna-Matthews-Olson (FMO) complex, a key component of green sulfur bacteria’s machinery for photosynthesis. It’s been a historical favorite for such research because we’ve long known its structure and it’s fairly easy to work with.

Previous experiments had seemed to show light-sensitive molecules in this area in two different states at the same time — that’s quantum weirdness — but the effect lasted more than 1 picosecond, which is much longer than expected. This new study shows that it was really just regular vibrations in the molecules, nothing quantum about it.

But researchers have been excited about the possibilities of quantum biology for years, so having disproved the earlier experiments, the authors wanted to find some new evidence of their own. “We wondered if we might be able to observe that Schrödinger cat situation,” says co-author Thomas la Cour Jansen in a press release.

And observe it they did! With a technique called two-dimensional electronic spectroscopy, researchers saw molecules in simultaneous excited states — quantum weirdness akin to a cat being alive and dead at the same time. What’s more, the effect lasted exactly as long as theories predicted it, suggesting this evidence of quantum biology will last. As the authors succinctly put it, “Thus, our measurements provide an unambiguous experimental observation of excited-state vibronic coherence in the FMO complex.” What could be simpler?

The results shed light (haha) on how to harvest energy from light, and the team thinks they’re “generally applicable” to a variety of systems, living and non-living alike. This means it could result in engineering benefits such as better solar panels, energy storage or even quantum computers. And, of course, updated textbooks for tomorrow’s lessons on photosynthesis.

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  • Michel Bluteau

    Wait for when they uncover quantum effects for the neuron 😉

    • Whothehell Cares

      At the macro level their are people who are both genius yet stupid at the same time.

      • Fred Scuttle

        Their shore are, ain’t they’re?

        • Anonymous9559

          Genius :)

      • Oliver

        There not their are you one of those stupid geniuses.

        • Whothehell Cares

          No, I’m just mediocre, and have no compulsive obsessive need for spelling police.

    • jonathanpulliam

      Trump is your mother/ Trump is your sister.

      I wonder why the snarky comments on this article are SO OFF-TOPIC.

      Show your ignorance much. This article is something I would use to wipe my butt in camping trip

    • Joe Vargas

      Absolutely. The Penrose Hameroff theory of quantum consciousness pertaining to the biological microtubules of the neurons becomes more and more real. Which would imply that AI will and can never be conscious, no matter how successful we are at ‘mapping’ the brain… unless you can create artificial microtubules that can trap those quantum “consciousness” particles (whatever that is ultimately determined to be – part of dark matter?) that provide us our unique ability for imaginative self awarness.

  • InspiredbyGod

    Amazing! And to think that this complex biological system, which was one of the very first life forms on the planet, developed by as series of non-directed random natural events. BTW, I have some real estate in Florida for sale if you’re interested.

    • lober star

      Actually as far as we can tell photosynthesis came about after the first billion years or so of life. I mean, that’s when the imaginary man in the sky from that one book willed it to be.

      • http://www.morningmail.org Belfast

        @thelober:disqus
        I dont understand you – you do you claim it came from chance associations of naturally occurring amino acids?

        • Fred Scuttle

          If you look at all the world’s religions making different, mutually exclusive claims, you’ll begin to understand that religion can’t keep its stories straight and it loses credibility.

          • Maia

            “religion can’t keep it’s stories straight”…I would just say that there are spiirtualities/religions (and variants) that do make exclusivity claims and doaccept other religions/spiritualities as valid, along with science and other branches of knowledge. What you are rightly objecting to is the *exclusivity* of most institutional forms that can and do lead to bigotry and violence, though not in all cases/ or in all people. The truth of the matter is much more nuanced than major world religions competing with each other. I would include ideologies of all sorts! It’s the “ONLY right view” attitude backed up by force that is the root of trouble.

  • Balaji Kartha

    this is just wow! Love it!

  • Maia

    There are some brilliant in-depth books coming out now in this emerging field of quantum biology and biophysics in general, from physicists themselves and allies in other fields.

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