Improving quantum gates using pulse programming

Abstract

Quantum computers are expected to revolutionise computing. An essential step towards that is to implement high fidelity quantum gates. In the thesis, we try to build an universal SU(2) gate set consisting of Z gate, X(π/2) gate and cross resonance gate, robust to various noises using Q-CTRL Boulder Opal. Q-CTRL have demonstrated techniques to improve quantum gates by 10x reduction in coherent error. We make use of these techniques to create better universal gates and compare their efficiency in IBM superconducting qubits. We optimise X(π/2) pulse for dephasing noise and control amplitude error and compare the control error robustness of optimised pulse against Gaussian pulse, DRAG pulse calibrated for leakage error, DRAG pulse calibrated for phase error and IBM default pulses. We also optimise cross resonance gate against cross talk noise and study its robustness theoretically