| 总结: | <p>Coherently oscillating radical pairs are an important chemical system that can surprisingly appear in different domains, such as avian magnetoreception or as the basis of a qubit for quantum computation. This thesis is concerned with studying this system in different areas, focusing on simulations and the development of new computational tools.</p>
<p>First, we present two studies on avian magnetorecception. One is about how isotopic substitutions can affect the hypothesised compass mechanism of birds. The results of this study are planned to be used in future spectroscopic studies as well as behavioural experiments aimed at elucidating the origin of magnetic sensing in avian species. The other study involves examining the effect of stochastic, time-dependent magnetic fields on the compassmechanism. This study compares theoretical findings with behavioural experiments and provides evidence that the action-spectrum histogram, an approximate theoretical tool for quantifying the effect of radiofrequency noise, remains accurate in most circumstances.</p>
<p>In addition, we present a study on the design of EPR pulse sequences for organic molecular electron spin qubits. The study builds on existing work on this topic and demonstrates that previous studies had distinct flaws. As a result, a number of enhancements are proposed for producing improved pulse sequences, and an example of successful experimental use of pulse sequences is presented in one of the appendices. In addition, the study quantifies the effects of relaxation and nuclear spins on the performance of quantum logic gates.</p>
<p>The final chapter focuses on new additions to the software programme <em>Mol- Spin</em>, which is an advanced platform for calculations involving spin dynamics. These new additions are centred on the implementation of the stochastic Schrödinger equation and recent advances in the estimation of quantum mechanical traces. When you combine these methods with careful engineering, the use of modern linear algebra algorithms, and new ways to reduce the time it takes to integrate certain systems, you get a full toolkit that can simulate systems that weren’t possible before. For instance, the singlet yield profile of a simulation of a system with 14 nuclear spins that follows the trajectory of a molecular dynamics simulation of a protein is shown in this chapter.</p>
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