Where quantum meets the rest of the world

A quantum system interacting with an environment can behave very differently to when it is in isolation. This can be a problem when modelling messy biological systems – how do I describe the molecule I’m interested in without describing the rest of the surrounding chemical soup?

In a recent manuscript that’s now in press with the New Journal of Physics, we introduced a technique to more clearly distinguish the boundary between such open quantum systems and their environments. This technique uses a feature of quantum mechanics that allows one to ‘mix-up’ different parts of a combined system in ways that don’t make sense in classical physics. By mixing the open system with its environment in just the right way, we can come very close to isolating the part of the combined system which we are interested in.

We went on to use our technique to model the behaviour of several example systems, including the well-studied Fenna-Matthews-Olsen (FMO) complex – involved in bacterial photosynthesis. In future, we hope to use our method to further understand how energy is transported in open quantum systems, perhaps influencing the design of quantum devices such as solar cells or chemical sensors.

The authors of this work include: Felix Pollock, Erik Gauger and Brendon Lovett as well as frequent QuNaT collaborators Ahsan Nazir and Dara McCutcheon.