Atom waves in passing

Jinxian Guo, L. Q. Chen, Peiyu Yang +6 more

In studying quantum correlation and quantum memory of continuous variables of light fields and atoms, a crucial step is the retrieval of the quantum fields by converting an atomic spin wave to light, and retrieval efficiency is a crucial parameter. In this Letter, we implement a double-pass Raman scheme in Rb87 by incorporating coherent feedback. We find that the transfer efficiency from an atomic spin wave, which is generated from a Raman process in a high gain regime, to light fields is enhanced by the double-pass scheme as compared to the commonly used single-pass scheme. An atomic spin wave as high as 88% is read out, limited only by decoherence of the atomic spin waves. Our analysis shows that the enhancement effect is because a double-pass scheme introduced the coherent feedback mechanism which selects the spatial mode of an atomic spin wave via the correlated optical field and enhances the coupling efficiency between the atom and light. The correlations between the write-in and readout signals generated in such a two-pass Raman process are also better than the single-pass case. We believe such a two-pass scheme with feedback mechanism should be useful for studying continuous variables in quantum systems.

Robert Pool

Paul R. Heyl

James Glanz

A Japanese team has come up with a striking demonstration of the wavelike nature of matter. Using optical principles to control the quantum-mechanical waves of neon atoms, the researchers coaxed the atoms to form a minute physical image. They passed the waves through a computer-generated hologram, an apparently meaningless pattern in a membrane that caused the atom waves to interfere and create an intelligible image—the letters NEC—on a detector.

Jacquelyn Ho

V.G. Baryshevsky, D V Baryshevsky

It is shown that under atomic or molecular interaction with a light wave there appear P and T non-invariant effects of spin rotation and spin dichroism. Effects of P and T non-invariant rotation and birefringence appear depending on the polarization of the atomic or molecular ensemble.