Electron spin relaxation can enhance the performance of a cryptochrome-based magnetic compass sensor
Daniel R Kattnig 1, Jakub K Sowa 1,4, Ilia A Solov'yov 2,3 and P J Hore 1
Published 9 June 2016 • © 2016 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft
New Journal of Physics, Volume 18, June 2016
Author affiliations
1 Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ, UK
2 Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
3 On leave from A. F. Ioffe Physical Technical Institute, Politechnicheskaya Str. 26, 194021 St. Petersburg, Russia
4 Present address: Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK.
Dates Received 21 March 2016 Accepted 19 May 2016 Published 9 June 2016
Citation: Daniel R Kattnig et al 2016 New J. Phys. 18 063007
Abstract
The radical pair model of the avian magnetoreceptor relies on long-lived electron spin coherence. Dephasing, resulting from interactions of the spins with their fluctuating environment, is generally assumed to degrade the sensitivity of this compass to the direction of the Earth's magnetic field. Here we argue that certain spin relaxation mechanisms can enhance its performance. We focus on the flavin–tryptophan radical pair in cryptochrome, currently the only candidate magnetoreceptor molecule. Correlation functions for fluctuations in the distance between the two radicals in Arabidopsis thaliana cryptochrome 1 were obtained from molecular dynamics (MD) simulations and used to calculate the spin relaxation caused by modulation of the exchange and dipolar interactions. We find that intermediate spin relaxation rates afford substantial enhancements in the sensitivity of the reaction yields to an Earth-strength magnetic field. Supported by calculations using toy radical pair models, we argue that these enhancements could be consistent with the molecular dynamics and magnetic interactions in avian cryptochromes.
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