You can find the online document here.
Publication appeared in Scientific Reports
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Shown is the experimental implementation of two concatenated CNOT gates. The input is set by a polariser, which can be followed by a local unitary operation (LU). The two gates are connected by fibers. Different matrices A can be implemented by adapting the LUs, and different states |b〉 by adapting the input state. The figure shows the most general case of two concatenated CNOT gates, combined with general LUs.