Figure 2
From: Simplified entanglement swapping protocol for the quantum Internet
Sketch of the entanglement swapping protocol composed of three well-defined sectors: four independent EPR sources of the \(\left| {\beta_{00} } \right\rangle\)-type, three quantum repeaters between those sources, and the density matrix of the final state \(\rho_{{\left| {\beta_{00} } \right\rangle }}\). The application of the protocol is carried out by grouping the states of the \(\left| {\beta_{00} } \right\rangle\)-type in pairs until reaching a single final state between the extreme qubits q[0] and q[7], thus reaching the maximum extension of the entanglement range for this configuration.
