Generation of superpositions of coherent states on a circle

S. Szabo, Петер Адам, József Janszky +1 more

An efficient method of quantum state engineering based on discrete superpositions of coherent states is presented. A systematic method is developed for obtaining optimized superpositions from the one-dimensional representation of the desired state. It is shown that superposition of even a small number of coherent states put along a straight line or on a circle in phase space can approximate nonclassical field states with a high degree of accuracy. An experimental scheme is proposed for generating equidistant coherent-state superpositions on a circle with arbitrary coefficients. \textcopyright{} 1996 The American Physical Society.

M. A. del Olmo, José A. González

Stephan De Bièvre, JOSÉ A. GONZÁLEZ

Chen Mei-Feng

A scheme is presented for generating a four-photon coherent state via the degenerate Raman interaction. The scheme does not need classical fields to manipulate the atoms. Its another advantage is that the atomic spontaneous emission can be neglected. Therefore, the coherence of the system may be better maintained. The scheme can be generalized to generate superposition of 2 n coherent states and superposition of 2 n two-mode coherent states. The coherent states in each mode are on a circle symmetrically.

József Janszky, P. Domokos, Петер Адам

As a generalization of the optical Schr\"odinger cats, discrete sets of coherent states are considered on a circle in the \ensuremath{\alpha} plane. It is shown that simple superpositions of Schr\"odinger cats exhibit amplitude squeezing, similarly to the case of a superposition of several coherent states along a straight line that shows quadrature squeezing. The interference fringes between the coherent states form the annuli of the Fock states in the Wigner-function picture. It is also shown that a continuous superposition of coherent states on a circle can serve as a basis for the representation of any state.

Chuan-hua Dong