On the application of theoretical multi-dimensional coherence spectroscopy techniques to discrete quantum systems
David J. Ing
Multi-dimensional coherence spectroscopy (MDCS) is a powerful technique that allows insight about the energy dynamics of quantum systems, on the timescale in which they occur. This work focuses on the application of this technique to predict quantum noise characteristics of some known systems. It begins with an explanation of what noise is, and follows with a derivation of the equations used throughout the rest of the work. Chapter 3 explores the possibility of determining the spatial correlations of noise, via the use of the Bloch-Redfield equation - which quantifies the degree of correlation as a continuous variable - on a photosynthetic-inspired model. Not only is there a possibility to determine the degree of spatial correlation in the noise, it shows that the secular approximation – where small perturbations on the coherent dynamics of the system are discarded – is not valid when considering multi-dimensional (MD) spectra. The techniques are applied to the nitrogen-vacancy centre in chapter 4, with a focus on the temperature-dependent noise processes associated with the system. A prediction is made that this temperature-dependent noise – and the associated averaging processes – should be visible when conducting MDCS on the nitrogen-vacancy centre. Utilising noise, instead of suppressing it, is investigated in chapter 5, via the use of the decoherence probe system. In this set up, the noise experienced by a probe is measured, and a map is created. This chapter shows that not only does MDCS remove ambiguity in measuring a single probe, but when moving to a dual-probe system, it is possible to estimate the dipole orientation of quantum systems in the environment.
•May 28, 2018•0 citations