Quantum State Engineering by Superpositions of Coherent Statesalong a Straight Line in Cavity Quantum Electrodynamics

A scheme is proposed for generating the superpositions of several coherent states in a cavity field with dispersive cavity quantum electrodynamics (QED). In the scheme, a sequence of atoms interact dispersively with the cavity field, connected with a microwave source, and is manipulated by classical fields, followed by state-selective measurements. In this way, the cavity field is collapsed onto a superposition of several coherent states along a straight line with controllable coefficients.This scheme provides the possibility for quantum state engineering via coherent-state superpositions in cavity QED for the first time.