Optimizing control fields for diabatic protocols in the presence of noise

Quantum control techniques are employed to perform quantum algorithms inspired by the adiabatic quantum computing protocols in the presence of noise. First, we analyze the entanglement protocol for two qubits. In this case, we find that this protocol is very robust against noise. The reason behind this fact is related to the chosen Hamiltonians, where the ground state of the initial Hamiltonian is not affected by the noise. The optimal control solution, in this case, is to leave the system in its ground state and apply a fast pulse to entangle the qubits at the end of the time evolution. Second, we probe a system composed of three qubits, where the goal is to teleport the first qubit to the third qubit. In this case, the ground state of the system does not share the same robustness against noise as in the case of the entanglement protocol. To circumvent this problem, we propose the inclusion of a local control field that can drive the system to an intermediate state, which is more robust against noise in comparison to other states. The target state is also achieved by a fast pulse close to the final time. We find that this approach provides a significant gain and promises to improve the realization of quantum computing in the so-called noisy intermediate-scale quantum devices.