Single atom interferometers and Bloch oscillations in quantum walks

Abstract

The deliberate coherent manipulation of a single atom's spin and position in an optical lattice has great potential as a primitive for future quantum simulators. This thesis investigates position control on ultracold Caesium atoms by modulating the polarization of light in a state-selective optical lattice, allowing us to explore matter wave interference along flexible, digitally programmable trajectories. The effects on coherence and phase are explored in depth using atom interferometry; this is also used to demonstrate measurements of optical and inertial potential gradients. By performing a quantum walk in an inertial gradient, a quantum simulation of Bloch oscillations in an electric field could be run, showing the hallmark oscillations in the walk distribution width. We also investigate Landau-Zener tunneling in the quantum walk at extremely high strengths of the virtual electric field.