Spin-swap gate in the presence of qubit inhomogeneity in a double quantum dot

The effects of qubit inhomogeneity and gate imperfections on the swap operations in a quantum dot quantum computer were analyzed. A robust pulse sequence for swap operation in the presence of Zeeman inhomogeneity for quantum dots trapped electron spins and finite-time ramp-up of exchange coupling in a double dot was constructed. A square-pulse sequence was designed to perform swap in the presence of Zeeman inhomogeneity. It was found that the exchange Hamiltonian became less efficient in performing swap in the presence of qubit inhomogeneity.