Figure 5

Quantum repeater scheme with weak measurement and postselection. A probabilistic noiseless linear amplifier is applied to one of the two parties, via the implementation of a weak cross-Kerr interaction with an ancillary signal. This interaction emerges as a fourth order expansion of the dynamics of the signal and the ancilla coupled with a transmon quantum bit, modelled as a three level system, in a non-resonant regime. The ancilla is then measured, and the result is sent classically to Alice for post-selection.