Eur. Phys. J. D 49, 147-155 (2008)
https://doi.org/10.1140/epjd/e2008-00147-6

Decoherence caused by transient linear amplifiers

¹ Graduate School of Humanities and Sciences, Ochanomizu University, 2-1-1 Ohtsuka, Bunkyo-ku, Tokyo 112-8610, Japan
² CREST, Japan Science and Technology Agency, 1-1-9 Yaesu, Chuo-ku, Tokyo 103-0028, Japan

Corresponding author: ^a ban.masashi@ocha.ac.jp

Received: 15 March 2008
Revised: 5 July 2008
Published online: 30 July 2008

Abstract

Decoherence of nonclassical properties is studied for a photon system interacting with a transient environment which changes from a linear attenuator to amplifier during the time evolution. The sufficient condition for quadrature squeezing, sub-Poissonian photon statistics and entanglement to be completely destructed during the time-evolution is derived. The results are compared with those obtained for another model of the transient linear amplifier. Furthermore the decoherence caused by a environment which switches a linear amplifier to attenuator is also investigated.