Tang, Ho Lun2024-06-262024-06-262024-06-25vt_gsexam:41121https://hdl.handle.net/10919/119509Quantum Computation has attracted massive interest because of the recent technological advancement in both hardware and software suggesting the potential of quantum advantage. On the software side, hybrid classical-quantum algorithms are extensively studied as they can be implemented on the current noisy intermediate-scale quantum devices. On the hardware side, researchers are striving for faster and more noise-robustness quantum operations to achieve higher quantum processing power. The dissertation presents two topics in the above-mentioned aspects. The first one is constructing adaptive ans"atze for variational quantum eigensolver, one of the most promising hybrid algorithms. We present how to compress different required quantum resources by designing different ans"atze. The second topic is about designing fast entangling gates with a geometric approach. We show that the geometric approach can improve the existing numerical methods by locating the good initial guesses.ETDenIn CopyrightQuantum InformationDissertation