Monitoring bipartite entanglement in hybrid carbon nanotube systems via optical 2D photon-echo spectroscopy

► Entanglement of a pair of atomic qubits near a metallic carbon nanotube is considered. ► Coupling of qubits to the same plasmon resonance of the nanotube makes them entangled. ► Theory is proposed for detection and nonlinear optical monitoring of the phenomenon. ► Cross-peaks in 2D photon-echo spectra are indicative of the bipartite entanglement.