Lecturer: Scerri, Dale
Abstract:
Single spin sensors are able to give highly sensitive measurements of an external magnetic field, with Bayesian adaptive strategies shown to be able to reach the quantum limit of parameter estimation. Previous work has been done on sensing classical fields, be it static, periodic, or stochastic. However, little study has been done on how these strategies can be used to control the environment of the spin-sensor. In a solid state system such as a diamond NV centre, the dilute nuclear environment is the main cause of decoherence of the central spin, ultimately putting a cap on how sensitive these devices can be. In this work, we investigate how the back-action of performing Ramsey measurements on the central spin affects the latter's nuclear environment. We find that the resulting distribution of possible fields due to these surrounding spins narrows down, considerably enhancing the T2* time of the central spin.