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Title: Long-lived spin coherence in radical pair compass magnetoreception
Author: Hiscock, Hamish
ISNI:       0000 0004 7430 7259
Awarding Body: University of Oxford
Current Institution: University of Oxford
Date of Award: 2018
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The ability of night migratory birds to utilise the Earth's magnetic field as a directional cue is thought to arise from a light-activated radical pair reaction in the birds' eye. The field of magnetoreception encompasses a broad range of research areas, from behavioural experiments to theoretical studies. Unfortunately, the computational challenge presented by modelling the multinuclear organic radicals thought to be involved in the sensing mechanism severely hampers the interpretation of experimental results in the framework of the radical pair hypothesis. This thesis presents novel algorithms for more efficient simulation of multinuclear radical pairs as well as a discussion of the insights available from calculations using these new computational tools. I first present improved algorithms for simulating radical pair reactions in a static external magnetic field. With these more efficient algorithms, I am then able to explore in more detail the behaviour of different radical pair systems, and discuss their potential relevance to magnetoreception in Chapter 4. In particular, I examine whether a highly accurate 'compass needle' could arise from a radical pair sensor. One of the most significant behavioural observations in the field of magnetoreception is the finding that exceedingly weak time-dependent magnetic fields can disrupt magnetic orientation in birds. The added complexity of a time-dependent interaction means that simulating the experimental conditions is a considerable challenge. In Chapter 3 I present a calculation method based on a reformulation of Floquet theory which remains the only viable algorithm for modelling multinuclear radical pairs in an oscillatory magnetic field. In Chapter 5 I discuss the effect of these weak time-dependent fields on different candidate radical pairs, and examine the compatibility of the observed behavioural results with the radical pair hypothesis. Finally in Chapter 6 I present a new Information theory-based analytical tool which allows me to assess the accuracy of a radical pair compass without having to make assumptions about the signalling cascade. I consider how a radical pair compass would operate under low light conditions, and how the impact of the limited number of available photons could inform my computational analysis from previous chapters and in future work.
Supervisor: Manolopoulos, David ; Hore, Peter Sponsor: European Research Council
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available