Abstract
In this Letter, we propose an experimental scheme for the observation of a quantum anomaly—quantum-mechanical symmetry breaking—in a two-dimensional harmonically trapped Bose gas. The anomaly manifests itself in a shift of the monopole excitation frequency away from the value dictated by the Pitaevskii-Rosch dynamical symmetry [L. P. Pitaevskii and A. Rosch, Phys. Rev. A 55, R853 (1997)]. While the corresponding classical Gross-Pitaevskii equation and the hydrodynamic equations derived from it do exhibit this symmetry, it is—as we show in our paper—violated under quantization. The resulting frequency shift is of the order of 1% of the carrier, well in reach for modern experimental techniques. We propose using the dipole oscillations as a frequency gauge.
- Received 5 June 2010
DOI:https://doi.org/10.1103/PhysRevLett.105.095302
© 2010 The American Physical Society