The order-disorder transition in colloidal suspensions under shear flow
We study the order?disorder transition in colloidal suspensions under shear flow by performing Brownian dynamics simulations. We characterize the transition in terms of a statistical property of the time-dependent maximum value of the structure factor. We find that its power spectrum exhibits power-law behaviour only in the ordered phase. The power-law exponent is approximately ?2 at frequencies greater than the magnitude of the shear rate, while the power spectrum exhibits 1/f-type fluctuations in the lower frequency regime.
We investigated a Bose system confined in one-dimensional channel by using quantum Monte Carlo simulations. We observed temperature dependences of the superfluid density and two correlation functions along the tubal and the circumferential directions of the channel. As temperature is lowered, first the correlation develops along the circumference, and then it develops along the tubal and the Kosterlitz-Thouless (KT) phase appears at the temperature depending on the confining potential and the ratio of the circumferential length to the length of the channel. We found that the onset temperature of the superfluidity observed by a torsional oscillator measurement depends on the direction of the torsion in this system.