Concentration and distribution of entanglement based on valley qubits system in graphene

Exploiting the optical excitation selection rules in graphene quantum dots, we investigate theoretically the entanglement generation process and entanglement concentration process of valley qubits. Our protocol shows that the graphene-based quantum dots can be distributed in a maximally entangled state through the interaction with single photons. In our proposed scheme, the setups are simplified as only single-photon detection is required. This provides a fast, all-optical manipulation of on-chip qubits, which gives an effective way for quantum information processing in graphene-based solid qubits.