Last week Discover Magazine posted a fascinating article on the developing scientific field of quantum biology, titled "Is Quantum Mechanics Controlling Your Thoughts". The article begins by looking at new evidence which suggests that quantum effects (such as entanglement and tunneling) may be the mechanism behind biological processes such as photosynthesis and the sense of smell.
One of the most significant quantum observations in the life sciences comes from Fleming and his collaborators. Their study of photosynthesis in green sulfur bacteria, published in 2007 in Nature [subscription required], tracked the detailed chemical steps that allow plants to harness sunlight and use it to convert simple raw materials into the oxygen we breathe and the carbohydrates we eat. Specifically, the team examined the protein scaffold connecting the bacteria’s external solar collectors, called the chlorosome, to reaction centers deep inside the cells. Unlike electric power lines, which lose as much as 20 percent of energy in transmission, these bacteria transmit energy at a staggering efficiency rate of 95 percent or better.
The secret, Fleming and his colleagues found, is quantum physics... Instead of haphazardly moving from one connective channel to the next, as might be seen in classical physics, energy traveled in several directions at the same time. The researchers theorized that only when the energy had reached the end of the series of connections could an efficient pathway retroactively be found. At that point, the quantum process collapsed, and the electrons’ energy followed that single, most effective path.
Electrons moving through a leaf or a green sulfur bacterial bloom are effectively performing a quantum “random walk”—a sort of primitive quantum computation—to seek out the optimum transmission route for the solar energy they carry. “We have shown that this quantum random-walk stuff really exists,” Fleming says.
These new findings are important to the controversial idea of 'quantum consciousness', as they may refute two of the main arguments against the idea: (a) That quantum effects won't occur at the macro level of biological systems, and (b) That it is too warm in the human brain for these quantum effects to occur. And at the end of the article they address this issue, talking to the pioneering researcher in the field (and an old friend of ours here at TDG) Stuart Hameroff. Although the article's author does note that quantum consciousness is still a speculative idea, the complete article does bring some context (and respectability) to the area:
It is still a long way from Hameroff’s hypothetical (and experimentally unproven) quantum neurons to a sentient, conscious human brain. But many human experiences, Hameroff says, from dreams to subconscious emotions to fuzzy memory, seem closer to the Alice in Wonderland rules governing the quantum world than to the cut-and-dried reality that classical physics suggests. Discovering a quantum portal within every neuron in your head might be the ultimate trip through the looking glass.
It would have been nice if the article had mentioned that Hameroff is not alone in his speculation: his 'co-speculator' is no less a personage than Sir Roger Penrose, and a separate, well-credentialed theorist on the idea (though he departs from the Hameroff-Penrose hypothesis on a number of points) is Henry Stapp. See Wikipedia's page on 'Quantum Mind' for a good starting point for further exploration. Makes you wonder whether Michael Shermer would like to retract some of his assertions in this Sci-Am column.
Now, heading off further down the rabbit hole than Discover (and certainly Michael Shermer) would like to go, 'quantum consciousness' may also provide a way of understanding near-death experiences and the possibility that consciousness lives on after physical death. When I spoke to Stuart a couple of years ago, this was his (speculative) explanation:
Under normal circumstances consciousness occurs in the fundamental level of spacetime geometry confined in the brain. But when the metabolism driving quantum coherence (in microtubules) is lost, the quantum information leaks out to the spacetime geometry in the universe at large. Being holographic and entangled it doesnt dissipate. Hence consciousness (or dream-like subconsciousness) can persist.
Parapsychology researcher Dean Radin is another who has pondered on a possible link between quantum effects and anomalous cognition - see his book Entangled Minds (Amazon US and UK) for more. Dean made a quick comment about the story on his blog last week as well.
Previously on TDG: