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Collisional deexcitation in a quasi-two-dimensional degenerate bosonic gas

2006; American Physical Society; Volume: 73; Issue: 2 Linguagem: Inglês

10.1103/physreva.73.020702

1538-4446

I. B. Spielman, Philip R. Johnson, J. H. Huckans, Chad Fertig, S. L. Rolston, William D. Phillips, J. V. Porto,

Quantum, superfluid, helium dynamics

We separate a Bose-Einstein condensate into an array of 2D sheets using a 1D optical lattice, and then excite quantized vibrational motion in the direction normal to the sheets. Collisions between atoms induce vibrational de-excitation, transferring the large excitation energy into back-to-back outgoing atoms, imaged as rings in the 2D plane. The ring diameters correspond to vibrational energy level differences, and edge-on imaging allows identification of the final vibrational states. Time dependence of these data provides a nearly complete characterization of the decay process including the energies, populations, and lifetimes of the lowest two excited vibrational levels. The measured decay rates represent a suppression of collisional de-excitation due to the reduced dimensionality, a matter wave analog to inhibited spontaneous emission.