Longitudinal atom optics : measuring the density matrix of a matter wave beam

Subhadeep Gupta, David A. Kokorowski, Richard A. Rubenstein +1 more

Richard A. Rubenstein, David A. Kokorowski, Al-Amin Dhirani +7 more

We present the first measurement of the longitudinal density matrix of a matter-wave beam. Using a unique interferometric scheme, both the amplitude and phase of off-diagonal density matrix elements were determined directly, without the use of traditional tomographic techniques. The measured density matrix of a doubly amplitude modulated atomic sodium beam compares well with theoretical predictions.

Arnaud Landragin, Philippe Bouyer

David A. Kokorowski, Tony Roberts, Richard A. Rubenstein +2 more

A detuned, radiofrequency field interacting with atoms in an atomic beam constitutes a beamsplitter in longitudinal momentum space. Using such beamsplitters, we have constructed a longitudinal atom interferometer in a generalization of Ramsey's classic SOF configuration. This interferometer is well-suited to studying the longitudinal coherence properties of matter-wave beams. We report on two such experiments, including a deconvolution of the longitudinal density matrix of an atomic beam, and a search for longitudinal coherences coming from our supersonic beam source.

Al-Amin Dhirani, David A. Kokorowski, Richard A. Rubenstein +5 more

Two separated oscillatory fields, if tuned to different frequencies, can generate or interrogate longitudinal momentum coherences in a beam of two-state particles. We demonstrate that use of differentially detuned separated oscillatory fields is an efficient method to determine the longitudinal density matrix of a particle beam.