# James March

I am currently studying for a PhD under the supervision of Dr Gavin Morley. I began studying for my PhD in October 2018, after completing the Physics MSci course at the University of Nottingham.

My project is entitled "Towards Placing a Nanodiamond Containing a Negaitvely Charged Nitrogen Vacancy Defect in a Mesoscopic Superposition". It has been proposed that a levitated nanodiamond containing a negatively charged nitrogen vacancy (NV-) defect could be used to attempt to place a relatively massive object (∼10-15 kg) in a spatial superposition. The proposals exploit the favourable spin properties of the NV- defect, such as initialisation via optical pumping and manipulation using microwaves. The motion of the centre of mass of the nanodiamond is coupled to the spin of the defect via a magnetic field gradient. After initialising the spin of the defect into a superposition of the form $\frac{\ket{\beta}(\ket{|1>} + \ket{|-1>})}{\sqrt{2}}$, the magnetic field gradient will act to separate the |$\ket{\pm1}>$ components, placing the centre of mass state in a spatial superposition.

My project aims to achieve spin manipulation and control of NV- defects within levitated nanodiamonds, a key aspect of the proposals detailed above. We are proceeding with a magneto-gravitational trap as these have been demonstrated to stably levitate nanodiamonds at high vacuum.

james.march@warwick.ac.uk

Warwick Diamond Research Group
Department of Physics
University of Warwick