Figure 2
From: Generating multi-atom entangled W states via light-matter interface based fusion mechanism
The setup for fusion of three W states.
D1, D2 and D3 denote the atomic detectors. N-atom W state 
, M-atom W state 
and T-atom W state 
are fused into a (N + M + T − 3)-atom W state 
. If the fusion process fails, the three W states 
, 
and 
can be re-fused by the same procedure.
