Ultrafast quantum gates for trapped neutral atom qubits

Abstract

Trapped neutral atom system has become an emerging platform for the implementation of quantum information processing with the recently developed techniques of atom-by-atom assembly and the Rydberg excitation. However, environmental noise and parameter errors currently prevent this system from performing quantum operations of large numbers and high fidelity to be required for obtaining the quantum advantages. In this thesis, we consider the conjunction of trapped neutral atom qubit and ultrafast coherent control. We show robust and selective excitations of the atomic system can be implemented by a shaped ultrafast pulse, and how to implement very fast quantum gate for the neutral atom qubit with ultrafast pulses. Then, utilizing the pulse shaping for the qubit controls, we propose and experimentally demonstrate the ultrafast Berry-phase gate which uses only geometric phase to control atomic clock-state qubit with both the rapidity and robustness against parameter errors. Finally, how these ideas can be applied to the Rydberg excitations in order to implement fast and robust multi-qubit controls is suggested.