Experimental implementation of high-fidelity unconventional geometric quantum gates using an NMR interferometer

Abstract

Following a key idea of unconventional geometric quantum computation developed earlier [S. L. Zhu and Z. D. Wang, Phys. Rev. Lett. 91, 187902 (2003)], here we propose a more general scheme in such an intriguing way: ${\ensuremath{\gamma}}_{d}={\ensuremath{\alpha}}_{g}+\ensuremath{\eta}{\ensuremath{\gamma}}_{g}$, where ${\ensuremath{\gamma}}_{d}$ and ${\ensuremath{\gamma}}_{g}$ are respectively the dynamic and geometric phases accumulated in the quantum gate operation, with $\ensuremath{\eta}$ as a constant and ${\ensuremath{\alpha}}_{g}$ being dependent only on the geometric feature of the operation. More interestingly, we demonstrate an experiment to implement a universal set of such kind of generalized unconventional geometric quantum gates with high fidelity in an NMR system.