Controlled-phase operation on two remote charge qubits via conditional electron dynamics in auxiliary structure

We study a possibility of implementation of two-qubit operations in an array of semiconductor quantum-dot-based charge qubits without the use of direct interqubit coupling. For that purpose, we exploit a sequence of laser-induced single-electron transfers in an auxiliary quantum dot structure whose transport properties depend on qubit states. As is demonstrated, it brings about the accumulation of additional phases that are specific for each of two-qubit logical states. Those phases depend on the laser and structure parameters. As the result, choosing them appropriately, one can obtain the desired two-qubit phase evolution.