photosynthesis, electrons, consciousness

Though this fascinating news story, Untangling the quantum entanglement behind photosynthesis is about quantum mechanical effects in the optimizing of light absorption by chlorophyl molecules in photosynthetic bacteria, it should thrill the people who study consciousness via cognitive neuroscience--especially those like Roger Penrose, who say the computational model doesn't amount to an explanation of consciousness unless the computational brain is understood as a quantum mechanical system. But the conventional wisdom (which has only recently come into serious question) holds that quantum mechanical effects like entanglement only become observable in exotic laboratory conditions, and probably don't occur at all in the relatively "hot and noisy" environment of the brain. The parrying argument from Pensrose and others was the hypothesis that certain very tiny "microtubules," which had been observed in neurons, might provide enough shelter from the brain's internal "heat and noise" for such effects as quantum entanglement to arise in the brain. The next step is to wonder if those otherwise rather mysterious microtubule structures exist for that purpose--to create entanglement-friendly conditions the brain can exploit for their awesome computational power, just as any other "quantum computer" does. Critics remained skeptical.

So along comes this news story about the quantum entanglement of electron pairs playing an observable role in photosynthesis. It makes no mention of neurons but I bet the microtubules people will be all over this thing like qualia on rice.

I hope this remarkable new work on photosynthetic bacteria leads to even more funding for research on quantum effects in the human brain, which might somehow "solve" the Hard Problem of consciousness. I don't pretend to understand it. Every aspect of our experience gets encoded into coordinated electrochemical flows of firing and non-firing trillions of networked neurons, and somehow consciousness is the result. Neurons and glia, configured in myriad stacked webs, such that it all somehow gives rise to--experience!

Then I think of qualia like the color blue, the flavor of stawberries, the timbre of a bell, and I can't imagine how they arise from computation. It's much easier to imagine the gist of how the sense organs of sight, olfaction, and hearing are able to take in data from the environment and encode it into electrochemical information for the brain's neural network to "process" somehow; it's much harder to imagine any "process" by which those electrochemically encoded data could eventuate in what I experience as those phenomena, when I impale this strawberry with a blue handled fork and take a bite as a distant bell tower rings the time.

I think I get the layman's gist of the neurology of a sea slug or a bacterium exhibiting a tropism and locomoting away from hydrochloric acid. What baffles me about consciousness--this emergent property of the brain--is just how it emerges.

Excerpts below from http://www.physorg.com/news192726440.html

The schematic on the left shows the absorption of light by a light harvesting complex and the transport of the resulting excitation energy to the reaction center through the FMO protein. On the right is a monomer of the FMO protein, showing also its orientation relative to the antenna and the reaction center. The numbers label FMO's seven pigment molecules. Image from Mohan Sarovar

Researchers with the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC), Berkeley have recorded the first observation and characterization of a critical physical phenomenon behind photosynthesis known as quantum entanglement.

Previous experiments led by Graham Fleming, a physical chemist holding joint appointments with Berkeley Lab and UC Berkeley, pointed to quantum mechanical effects as the key to the ability of green plants, through photosynthesis, to almost instantaneously transfer solar energy from molecules in light harvesting complexes to molecules in electrochemical reaction centers.

"This is the first study to show that entanglement, perhaps the most distinctive property of quantum mechanical systems, is present across an entire light harvesting complex," says Mohan Sarovar, a post-doctoral researcher under UC Berkeley chemistry professor Birgitta Whaley at the Berkeley Center for Quantum Information and Computation. "...this is the first instance in which entanglement has been examined and quantified in a real biological system." PHYSorg.com 10 May 2010.

www.physorg.com/news192726440.html