Nongeometric conditional phase shift via adiabatic evolution of dark eigenstate: a new approach to quantum computation

We propose a new approach to quantum phase gates via adiabatic evolution. The conditional phase shift is of neither dynamical nor geometric origin; it arises from the adiabatic evolution of the dark state itself. Taking advantage of the adiabatic passage, this kind of quantum logic gate is robust against moderate fluctuations of experimental parameters. Compared with geometric phase gates, the procedure is simple and the fidelity may be improved. A brief introduction to these quantum phase gate is given.