Department of Physics, University of Massachusetts Boston, Boston Massachusetts 02125, USA.
Phys Rev Lett. 2010 Aug 27;105(9):095302. doi: 10.1103/PhysRevLett.105.095302.
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.
在这封信件中，我们提出了一个在二维谐振子束缚玻色气体中观测量子反常——量子力学对称性破缺——的实验方案。反常表现为磁单极激发频率偏离由 Pitaevskii-Rosch 动力学对称性[L. P. Pitaevskii 和 A. Rosch, Phys. Rev. A 55, R853 (1997)]所预言的值。尽管相应的经典 Gross-Pitaevskii 方程及其推导出的流体力学方程确实表现出这种对称性，但正如我们在论文中所展示的，这种对称性在量子化下被违反了。由此产生的频率偏移大约是载波的 1%，这在现代实验技术的可达到范围之内。我们建议使用偶极振荡作为频率量规。
