Quantum Repeater — Entanglement Swapping Chain

EPR pairs generated locally, swapped through nodes to extend entanglement over arbitrary distances.

End-to-end fidelity:
F = 1.000
Without repeaters:
F_direct = 0.000
Segments: 4
Entanglement swapping:
Bell measurement at node merges two EPR pairs → one long-range pair
Fidelity after n swaps:
F_n = f(F₀)^n
Purification can boost F before swapping