We discuss and implement experimentally a method for characterizing quantum gates operating on superpositions of coherent states. The peculiarity of this encoding of qubits is to work with a non-orthogonal basis, and therefore some technical limitations prevent us from using standard methods, such as process tomography. We adopt a different technique, that relies on some a-priori knowledge about the physics underlying the functioning of the device. A parameter characterizing the global quality of the quantum gate is obtained by \virtually" processing an entangled state.
@article{arxiv.1105.5510,
title = {A method for characterizing coherent-state quantum gates},
author = {Rémi Blandino and Franck Ferreyrol and Marco Barbieri and Philippe Grangier and Rosa Tualle-Brouri},
journal= {arXiv preprint arXiv:1105.5510},
year = {2011}
}