Experimental demonstration of a Hadamard gate for coherent state qubits

In recent years coherent state qubits, |α〉 ± | - α〉 have gained much interest. The main reason is the promise to realize a universal set of coherent state quantum gates with a relative low overhead using, only linear optics and photon counters. A universal set of gates consists of a single mode and a two mode phase gate and a Hadamard gate. The Hadamard is the gate that transforms one set of basis states into the conjugate basis, e.g | ± α〉 - | - α〉. Here we present an experimental demonstration of a Hadamard gate for coherent state qubits. The implementation is based on the scheme proposed by Marek and Fiurasek (2010).