ISSN:
1434-6036
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract Using neutron scattering we have studied the behaviour of an oscillatory soft mode in a thermoconvective liquid crystal. As a function of an applied vertical temperature difference ΔT the behaviour of the soft-mode frequency defines four regimes, separated by cross-over values at which spatio-temporal symmetry is broken. Breaking of time symmetry manifests itself in different phase relations among localized oscillators. Incomplete softening at the convection threshold ΔT c is interpreted as anharmonic coupling to low-energy, internal director fluctuations in the nematic. Subtracting the anharmonic contribution, the renormalized frequency squared gives a susceptibility critical index γ for each of the four regimes. The values range between 1.1 and 2.7, indicative of a change of the spatial dimensionality as ΔT→ΔT c. The widths in ΔT of the regimes converge as the Feigenbaum ratio (∼4.6), and the meaning of this is discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01304238
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