Atomic Properties & Red Laser System for a Sr-Based Rydberg Quantum Simulator

Abstract

Quantum simulation seeks to study physical models that are beyond the reach of classical computation. Within this scope, ICFO’s Ultracold Quantum Gases group is developing a strontium Rydberg atom array platform to simulate high-dimensional lattice gauge theories with plaquette interactions, many-body couplings yet to be experimentally realised. This experiment requires a detailed theoretical understanding and a technically involved setup. This master’s thesis contributes to both fronts. On the theoretical side, we studied strontium’s clock state and its magnetic-field-induced excitation, characterised the properties and interactions of Rydberg states, and analysed a scheme for selective Rydberg excitation based on light shifts. Our results show that the clock transition can be broadened to the 0.1 mHz range to enable excitation, that Rydberg states with n ≈ 60 offer favourable interaction landscapes and coupling strengths, and that selective excitation should be feasible by scaling the intensity of optical tweezers. Experimentally, we implemented the core of the 689 nm laser system, including a slave diode for power amplification and an optical cavity for monitoring. We also verified the finesse of an ultrastable cavity for future frequency stabilisation and successfully tested the Pound-Drever-Hall locking technique on the monitoring cavity. Overall, these developments mark significant progress towards completing the experimental platform and provide a theoretical basis for future design choices. The future steps will focus on assembling the remaining experimental systems and testing our theoretical predictions.