Selective pulse implementation of two-qubit gates for spin-3/2 based fullerene quantum information processing

We propose two potentially practical schemes to carry out two-qubit quantum gates on endohedral fullerenes $N@C_{60}$ or $P@C_{60}$. The qubits are stored in electronic spin degrees of freedom of the doped atom $N$ or $P$. By means of the magnetic dipolar coupling between two neighboring fullerenes, the two-qubit controlled-NOT gate and the two-qubit conditional phase gate are performed by selective microwave pulses assisted by refocusing technique. We will discuss the necessary additional steps for the universality of our proposal. We will also show that our proposal is useful for both quantum gating and the readout of quantum information from the spin-based qubit state.