illuminating science

Yesterday was the School of Physical Sciences Poster Day at University of Queensland where I’m doing my PhD. Basically, it’s a day when all of the PhD students prepare posters on their work to be displayed, and they have a BBQ and everyone walks around and talks to people about their work. Part of it is that it’s a great way for everyone to learn a little more about the research activities other groups are doing (PhD students tend to be involved in pretty much everything!) but it’s also designed to give PhD students experience in presenting their work to other researchers, in preparation for doing just that at a real conference somewhere. To encourage people to participate, they award prizes for the best poster from each discipline (physics, maths and earth science) which includes a $500 travel grant to attend a conference. And hence this post, since I won the poster prize for physics It was for my poster “Quantum Mechanics in Biology”, which talks about my work in understanding the role of quantum mechanics in places like photosynthesis and vision. Just so we’re clear, I don’t believe that quantum mechanics is responsible for consciousness, and that quantum effects in the brain enable us to think - I find that too hard to swallow, although I’m open to being convinced. I’m really interested in more practical examples, like where biology has evolved to take advantage of all these weird quantum effects, like tunneling and particles being in two places at once, and used it to build high efficiency devices, like our eye. It’s a fascinating topic, and hopefully we’re contributing something useful by studying these systems from a physicists’ perspective. If you’re interested, here’s the abstract for my talk:

Quantum mechanics forms the basis of physics - but what role does it play in life? Of course, it determines the structure of proteins and the chemistry of bonds, but much more interesting is where biology has evolved to use uniquely quantum effects to do things better. Photosynthesis
and vision are just two examples - Roger Penrose and others have even suggested that quantum coherence is the basic of consciousness! However, for any of this to be possible, evolution would have to overcome the problem of strong decoherence from the “hot and wet” environment.

We’ve shown that the interaction of biomolecules with the surrounding proteins and solvent can be described by the spin-boson model, which is very useful for studying decoherence and exhibits rich (non-trivial!) many body physics. We’ve then used these models to study systems of biomolecules coupled by FRET (Fluorescence Resonant Energy Transfer), in particular the light harvesting complexes of photosynthesis. And it may be that FRET spectroscopy might be useful to experimentally investigate the cross-over from classical to quantum behaviour.

Now I’ve just got to decide where I want to go!