Friday, June 17, 2011

Quantum life

I have a feature in this week’s Nature on quantum biology, and more specifically, on the phenomenon of quantum coherence in photosynthesis. Inevitably, lots of material from the draft had to be cut, and it was a shame not to be able to make the point (though I’m sure I won’t be the first to have made it) that ‘quantum biology’ properly begins with Schrödinger’s 1944 book What is Life? (Actually one can take it back still further, to Niels Bohr: see here.) Let me, though, just add here the full version of the box on Ian McEwan’s Solar, since I found it very interesting to hear from McEwan about the genesis of the scientific themes in the novel.

The fact is, no one understands in detail how plants work, though they pretend they do… How your average leaf transfers energy from one molecular system to another is nothing short of a miracle… Quantum coherence is key to the efficiency, you see, with the system sampling all the energy pathways at once. And the way nanotechnology is heading, we could copy this with the right materials… Quantum coherence in photosynthesis is nothing new, but now we know where to look and what to look at.

These words are lifted not from a talk by any of the leaders in this nascent field but from the pages of Solar, a 2010 novel by the British writer Ian McEwan. A keen observer of science, who has previously scattered it through his novels Enduring Love and Saturday and has spoken passionately about the dangers of global warming, McEwan likes to do his homework. Solar describes the tragicomic exploits of quantum physicist, Nobel laureate and philanderer Michael Beard as he misappropriates an idea to develop a solar-driven method to split water into its elements. The key, as the young researcher who came up with the notion explains, is quantum coherence.

“I wanted to give him a technology still on the lab bench”, says McEwan. He came across Fleming’s research in Nature or Science (he forgets which, but looks regularly at both), and decided that this was what he needed. After ‘rooting around’, he felt there was justification for supposing that a bright postdoc might have had the idea in 2000. It remained to fit that in with Beard’s supposed work in quantum physics. This task was performed with the help of Cambridge physicist Graham Mitchison, who ‘reverse-engineered’ Beard’s Nobel citation which appears in Solar’s appendix: “Beard’s theory revealed that the events that take place when radiation interacts with matter propagate coherently over a large scale compared to the size of atoms.”

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