Sunday, April 15, 2007

The Many Paths of Light

Seems news about a particular topic come in groups. Whether that is just due to chance, some sort of synchronicity or the "pit bull effect**". At any rate more news about light and photosynthesis, this time from physics.org:

Quantum secrets of photosynthesis revealed from PhysOrg.com

"Through photosynthesis, green plants and cyanobacteria are able to transfer sunlight energy to molecular reaction centers for conversion into chemical energy with nearly 100-percent efficiency. Speed is the key - the transfer of the solar energy takes place almost instantaneously so little energy is wasted as heat. How photosynthesis achieves this near instantaneous energy transfer is a long-standing mystery that may have finally been solved.

[...]"

Image from http://www.vdacs.virginia.gov

Note the emphasis on near 100% efficiency. Presumably they are referring to efficiency of conversion of light actually absorbed by the photosystems to chemical energy in the form of ATP and NADPH, not the conversions that take place in the Calvin cycle. According to the news reports, this efficiency results from the ability of individual photons to travel along different paths simultaneously effectively selecting the most efficient path.

This is an exciting discovery and one that needs to be watched closely because we may be able to take advantage of this principle to greatly improve solar cell efficiencies and develop efficient schemes based on photosynthesis for converting light energy to chemical energy. The other thing about this finding is that the photosystems in the chloroplast are doing what is essentially an exercise in quantum computing, which as noted in this introduction is still in its infancy. So here we have a discovery that may have important implications to two seemingly disconnected fields-energy production and computers.

**Note: the "pit bull effect" stems from my observation that reports of pit bull bites seem to come in clusters-perhaps because media attention gets focused on the breed because of one spectacular incident such as happened in Lawrence in the 1980's. Suddenly even a pit bull sneezing becomes big news for a time.

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