Observation of the Kibble–Zurek scaling law for defect formation in ion crystals

• DOI: 10.1038/ncomms3290
• Publication Date: 2013-08-07T09:52:51Z
• Authors: S. Ulm; J. Roßnagel; G. Jacob; C. Degünther; S. T. Dawkins; U. G. Poschinger; R. Nigmatullin; A. Retzker; M. B. Plenio; F. Schmidt-Kaler; K. Singer
• Keywords: Scaling law; Statistical Mechanics

Traversal of a symmetry-breaking phase transition at a finite rate can lead to causallyseparated regions with incompatible symmetries and the formation of defects at their boundaries. The defect formation follows universal scaling laws prescribed by the Kibble-Zurek mechanism (KZM) important to the study of phase transitions in fields as diverse as quantum and statistical mechanics, condensed matter physics and cosmology. Here, we observe the KZM in a crystal of cold trapped ions, which is conducive to the precise control of structural phases and the detection of defects. The experiment confirms a scaling law with an exponent of 2.68 +/- 0.06, as predicted from the KZM in the finite inhomogeneous case. Such precision makes it feasible to use ion crystals for quantitative tests of classical and quantum statistical mechanics.