Effect of shear on phase-ordering dynamics with order-parameter-dependent mobility: the large-n limit

The effect of shear on the ordering kinetics of a conserved order-parameter system with O(n) symmetry and order-parameter-dependent mobility Gamma(straight phi-->) approximately (1-straight phi-->(2)/n)(alpha) is studied analytically within the large-n limit. In the late stage, the structure factor becomes anisotropic and exhibits multiscaling behavior with characteristic length scales (t(2alpha+5)/ln t)(1/2(alpha+2)) in the flow direction and (t/ln t)(1/2(alpha+2)) in directions perpendicular to the flow. As in the alpha=0 case, the structure factor in the shear-flow plane has two parallel ridges.     

Comment on "Pushing the hyperpolarizability to the limit"

It is shown that energy/length scaling complicates maximizing the first hyperpolarizability of a single electron as a function of the potential. A more transparent formula for this hyperpolarizability is given. Examining this formula demonstrates that Zhou et al.(1) have not proved that modulated conjugation results in large hyperpolarizability.     

Some recent advances in the understanding of phase-ordering dynamics

We review some of our recent studies of phase ordering dynamics. Specifically, we describe results from numerical simulations of domain growth in systems with quenched disorder. We also present representative results from numerical studies of phase ordering dynamics in anisotropic systems.     

The two-loop vector form factor in the Sudakov limit

Recently two-loop electroweak corrections to the neutral current four-fermion processes at high energies have been presented. The basic ingredient of this calculation is the evaluation of the two-loop corrections to the Abelian vector form factor in a spontaneously broken SU(2) gauge model. Whereas the final result and the derivation of the four-fermion cross sections from evolution equations have been published earlier, the calculation of the form factor from the two-loop Feynman diagrams is presented for the first time in this paper. We describe in detail the individual contributions to the form factor and their calculation with the help of the expansion by regions method and Mellin–Barnes representations.