First paper of the year: Decoherence-assisted transport in a dimer system

The article, “Decoherence-assisted transport in a dimer system”, by Adriana Marais, Ilya Sinayskiy, Francesco Petruccione and Artur Ekert has been published online yesterday, 11 January 2012, in the 13 January 2012 issue of Physical Review Letters (Vol.108, No.2):

Structured environments for more efficient energy transfer processes in photosynthesis

Quantum coherence as a resource can vastly increase the speed and efficiency of energy transfer, and has recently been discovered to play a role in photosynthesis. Decoherence, a process resulting from inevitable system-environment interactions, would typically be thought to hinder such transfer. In the paper we show how decoherent interaction between a simple quantum system and an environment consisting of quantum spin-half particles can in fact enhance the probability of energy transfer across the system.

The detection of quantum coherence on unexpectedly long times scales in photosynthetic complexes, together with the remarkable efficiency with which such complexes are able to transfer energy, has led to much discussion about the role of the environment in the energy transfer process.  In photosynthetic complexes the light-harvesting pigments interact strongly with the polar protein-solvent environment. Traditionally, such systems are described by spin-boson models of excitons within a protein medium. We consider instead a spin environment, and show that the exciton – environment interaction in this case increases quantum efficiency, furthermore, that there exist parameter regimes for near perfect energy transport.

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DOI: 10.1103/PhysRevLett.108.020602