Hamiltonians for quantum computing
Vladimir Privman, Dima V. Mozyrsky, Steven P. Hotaling · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1997
We argue that the analog nature of quantum computing makes the usual design approach of constructing complicated logical operations from many simple gates inappropriate. Instead, we propose to design multi-spin quantum gates in which the input and output two-state systems (spins) are not necessarily identical. We outline the design criteria for such devices and then review recent results for single-unit Hamiltonians that accomplish the NOT and XOR functions.