Experimental demonstration of quantum secret sharing

We present a setup for quantum secret sharing based on energy-time entanglement. In opposition to known implementations using three particle Greenberger-Horne-Zeilinger (GHZ) states, our idea takes advantage of only two entangled photons created via parametric down conversion. However, the system comprising the pump plus the two down-converted photons bare the same quantum correlation and can be used to mimic three entangled qubits. The relatively high coincidence count rates found in our setup enable for the first time an application of a quantum communication protocol based on more than two qubits.