Evolution of cat states in a dissipative parametric amplifier: decoherence and entanglement Faisal A.A. El-Orany, J. Peřina, V. Peřinová and M. Sebawe Abdalla Eur. Phys. J. D, 22 1 (2003) 141-156 Published online: 13 December 2002 DOI: 10.1140/epjd/e2002-00234-8