We develop a scheme to generate number squeezing in a Bose-Einstein condensate by utilizing interference between two hyperfine levels and nonlinear atomic interactions. We describe the scheme using a multimode quantum field model and find agreement w
ith a simple analytic model in certain regimes. We demonstrate that the scheme gives strong squeezing for realistic choices of parameters and atomic species. The number squeezing can result in noise well below the quantum limit, even if the initial noise on the system is classical and much greater than that of a poisson distribution.
We present a quantum multi-modal treatment describing Electromagnetically Induced Transparency (EIT) as a mechanism for storing continuous variable quantum information in light fields. Taking into account the atomic noise and decoherences of realisti
c experiments, we model numerically the propagation, storage, and readout of signals contained in the sideband amplitude and phase quadratures of a light pulse. An analytical treatment of the effects predicted by this more sophisticated model is then presented. Finally, we use quantum information benchmarks to examine the properties of the EIT-based memory and show the parameters needed to operate beyond the quantum limit.
