Title: Application of phase estimation algorithms to improve diamond spin magnetometry Research Adviser: Dr.Gurudev Dutt Abstract: Precision measurements of weak magnetic fields with nanoscale spatial resolution is an outstanding challenge in many fields including medicine, biology, material science and physical science. It has already been demonstrated that a single electron spin formed by a defect color center in diamond, known as the notrogen-vacancy (NV) center, can serve as a highly sensitive magnetometer with nanoscale resolution even under ambient conditions. However, standard quantum sensing methods also have significant drawbacks. This include the limited dynamic range due to quantum phase ambiguity, the non-linearity in sensitivity over the detectable field range, requiring prior knowledge of a working point for accurate deconvolution etc. This thesis explores novel quantum control techniques such as the use of phase estimation algorithms (PEA) for magnetic field detection to address these issues. Unlike in the standard approach, PEA readout is linearly dependent with the field being sensed. PEA on oscillating (AC) magnetic fields can not only detect unknown field amplitudes but also allows detection of the field phase. The techniques developed here can potentially have broad applicability to a wide variety of solid-state quantum systems, and in the field of quantum control and measurement.