PRECISION MEASUREMENTS TO EXPLORE UNDERLYING GEOMETRIES AND INTERACTIONS IN A TRAPPED Ba+ ION

Abstract

The work described in this thesis consists of both theoretical and experimental research performed on single trapped ion. The barium ion, being a heavy multi-electron system, allows benchmarking of highly demanding ab-initio many body electronic structure calculations. The dipole forbidden transitions in barium ion also serves as a test bed for atomic parity non-conservation, geometric phase generation, optical qubit, etc. In this work, the possibility of measuring and quantifying geometric phase in two different symmetry of the underlying Hamiltonian has been studied. This study leads to the prospect of using dipole forbidden transition in barium ion as its possible test bed. However, it is essential to measure the quadrupole shift of this transition before implementing the geometric phase measurement protocol. In the experimental section of this thesis, precision measurement on the allowed dipole transition has been performed to benchmark the many body calculations required to study atomic parity non-conservation in barium ion. Further experiments has been performed in order to measure the quadrupole shift of the dipole forbidden transition. These measurements firmly sets the foundations for future measurements to be performed on both atomic parity non-conservation and implementation of geometric phase generation proposals as developed in the theoretical part of the thesis. This thesis contains a theoretical proposal to implement geometric phase generation protocol in a trapped barium ion using only electric fields. It further includes the first measurements of branching fraction of dipole allowed transition in barium ion with a precision well below 0.05% which allows us to discriminate between different many body calculations done with a precision of 1\%. In addition, this thesis lays the foundation to measure the more challenging electric quadrupole shift of the dipole forbidden transition in barium ion. This led to implementation of a fast optical qubit at a wavelength close to telecommunication wavelength.