Abstract
In a Bose-Einstein condensate, the excitation of a Bogoliubov phonon with low momentum (e.g., by a two-photon Bragg process) is strongly suppressed due to destructive interference between two indistinguishable excitation pathways. Here we show that scattering of this sound excitation into a double-momentum mode is strongly enhanced due to constructive interference. This enhancement yields an inherent amplification of second-order sound excitations of the condensate, as we confirm experimentally. We further show that due to parity considerations, this effect is extended to higher-order excitations.
Original language | American English |
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Article number | 010404 |
Journal | Physical Review Letters |
Volume | 101 |
Issue number | 1 |
DOIs | |
State | Published - 3 Jul 2008 |
Externally published | Yes |