Field and dipole squeezing in a driven degenerate Λ quantum-beat system

Abstract

The properties of field squeezing and atomic dipole squeezing in a coherent-microwave field driven degenerate Λ quantum-beat system were theoretically investigated. Numerical calculations indicate that the driving microwave may enhance or suppress both dipole squeezing and cavity-field squeezing, depending on the atomic energy level splitting and the microwave Rabi frequency. c Versita Warsaw and Springer-Verlag Berlin Heidelberg. All rights reserved. The fundamental property of squeezed states is that of reduced quantum fluctuations in one quadrature component of the field or atomic dipole. Squeezed field states have been extensively studied [1-9] due to their potential applications in optical communication, gravity wave detection, high-resolution laser spectroscopy and quantum information theory. Recent studies of the dynamical behaviors in a system consisting of an atom interacting with a cavity field in which the atom or the cavity mode is driven by an external coherent classical field have aroused some researchers' interest [6][7][8][9][10][11]. Li et al.[6] discussed field squeezing in a driven Jaynes-Cummings model. Villas-Boas et al. [7] investigated the field squeezing effect in a system where a three-level atom in the ladder configuration interacted simultaneously with a classical driving field and a cavity mode, and they obtained higher field squeezing. Their results were restricted to dispersive interaction and based on the adiabatic approximation.In this paper, unlike the aforementioned authors, instead of driving the dipole-allowed atomic transitions, we deal with a degenerate Λ quantum-beat system whose lower levels *