TY - JOUR
T1 - Critical dynamics of spontaneous symmetry breaking in a homogeneous Bose gas
JF - Science
JO - Science
SP - 167
LP - 170
DO - 10.1126/science.1258676
VL - 347
IS - 6218
AU - Navon, Nir
AU - Gaunt, Alexander L.
AU - Smith, Robert P.
AU - Hadzibabic, Zoran
Y1 - 2015/01/09
UR - http://science.sciencemag.org/content/347/6218/167.abstract
N2 - Cooling a physical system through a phase transition typically makes it less symmetrical. If the cooling is done very slowly, this symmetry change is uniform throughout the system. For a faster cooling process, the system breaks up into domains: The faster the cooling, the smaller the domains. Navon et al. studied this process in an ultracold gas of Rb atoms near its transition to a condensed state (see the Perspective by Ferrari). The authors found that the size of the domains froze in time in the vicinity of the transition and that it depended on the cooling speed, as predicted by theory.Science, this issue p. 167; see also p. 127 Kibble-Zurek theory models the dynamics of spontaneous symmetry breaking, which plays an important role in a wide variety of physical contexts, ranging from cosmology to superconductors. We explored these dynamics in a homogeneous system by thermally quenching an atomic gas with short-range interactions through the Bose-Einstein phase transition. Using homodyne matter-wave interferometry to measure first-order correlation functions, we verified the central quantitative prediction of the Kibble-Zurek theory, namely the homogeneous-system power-law scaling of the coherence length with the quench rate. Moreover, we directly confirmed its underlying hypothesis, the freezing of the correlation length near the transition. Our measurements agree with a beyond-mean-field theory and support the expectation that the dynamical critical exponent for this universality class is .
ER -