Quantum dynamics of gate operations on charge qubits

We present a detailed analysis of the time evolution of a charge qubit realized in the lowest bound states of a double well potential. A mechanism for quantum gate operations on this qubit is modeled by directly solving the corresponding time-dependent Schrödinger equation. We demonstrate that the mechanism induces complicated non-adiabatic time evolution of the qubit system. With ideal potentials and instantaneous switching, this mechanism is shown to be capable of carrying out a NOT gate operation, and rotations by π/4 and 3π/4 Effects of non-ideal potentials and smooth switching are also examined.