Friday, 21 June 2013

Plants doing quantum physics

This week the fledgling field of quantum biology took a major step forward with the publication of a significant study in Science.

In the study, scientist, Niek van Hulst, and colleagues at the Institute of Photonic Sciences in Castelldefels in Spain, outlined a extensive set of experiments which give the most concrete evidence yet of quantum principles being involved with the process of photosynthesis in plants. 
The study, whilst not the first to suggest that quantum processes are involved in photosynthesis, is important, as until now, no one had directly observed the impact of this kind of quantum mechanism at work, at room temperature.

As Jason Palmer writes: "Plants gather packets of light called photons, shuttling them deep into their cells where their energy is converted with extraordinary efficiency. [Š] An effect called a "coherence" helps determine the most efficient path for the photons. [....] The new study has been done painstakingly, aiming lasers at single molecules of the light-harvesting machinery to show how light is funnelled to the so-called reaction centres within plants where light energy is converted into chemical energy."

Quantum mechanics tends to be observed at very small, subatomic scales and at extremely cold temperatures. Organisms as large, wet and warm as plants have largely been understood using the principles of "classical physics".  But, the field of quantum biology has for some years now been suggesting a far deeper entanglement between large complex biological organisms and quantum mechanics.  Various research groups have shown that efficient energy transport in plants is connected to a quantum-mechanical phenomenon. In 2007, Berkeley Lab and the University of California published a paper in Nature that suggested that electronic quantum coherence played a role in photosynthesis.

This week's paper by the Institute of Photonic Sciences' underscores this, and provides compelling evidence. As Rienk van Grondelle of the Free University Amsterdam noted in an interview with the BBC, it is, "a very nice proof that the ideas that existed about these coherences are actually correct".

The research paves the way for far closer links between two fields of science - quantum physics and biology - often considered, with some humour, as polar opposites.  Greater collaborations between quantum physicists and biologists is likely to lead to important new insights in the coming years.  It is hoped by many scientists that understanding how quantum processes are involved in how plants harness energy could be applied to the development of, for example, more efficient solar cells, something which has been discussed for a few years now.

The field of quantum biology may just be coming of age.