Abstract
We study the collapse of an attractive atomic Bose-Einstein condensate prepared in the uniform potential of an optical-box trap. We characterize the critical point for collapse and the collapse dynamics, observing universal behavior in agreement with theoretical expectations. Most importantly, we observe a clear experimental signature of the counterintuitive weak collapse, namely, that making the system more unstable can result in a smaller particle loss. We experimentally determine the scaling laws that govern the weak-collapse atom loss, providing a benchmark for the general theories of nonlinear wave phenomena.
- Received 1 September 2016
DOI:https://doi.org/10.1103/PhysRevX.6.041058
Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.
Published by the American Physical Society
Physics Subject Headings (PhySH)
Popular Summary
Waves are all around us: Ripples on the surface of a pond, radio waves, and optical pulses in internet fibers are just a few examples. Many wave phenomena can be understood by approximating waves as noninteracting or linear, in which case their behavior is independent of their amplitude. However, many of the most interesting wave phenomena, such as rogue ocean waves and solitary waves in channels, occur when this approximation breaks down, and their behavior becomes nonlinear. Here, using atomic gas cooled to almost absolute zero temperature, we experimentally demonstrate a nonlinear wave phenomenon first predicted over 30 years ago.
A fascinating example of nonlinear behavior is wave collapse, in which one point of a wave grows in amplitude at the expense of the surrounding area. This collapse ultimately results in dissipation of the wave’s energy, as, for example, seen in whitecaps on choppy water. Extensive theoretical studies have suggested that wave collapse can be categorized as either strong or weak. While the more intuitive strong collapse has been observed, weak collapse has remained experimentally elusive. A particularly surprising prediction for weak collapse is that the dissipated wave energy actually decreases as the nonlinearity (which causes the collapse) is increased. Using a condensate with up to 200,000 atoms, we experimentally determine the scaling laws dictating weak collapse and find that our results are consistent with theoretical predictions.
We expect that our findings will pave the way for future studies of the dynamics of wave collapse and, more generally, nonlinear wave phenomena.