Globally-Linked Vortex Clusters in Trapped Wave Fields

We put forward the existence of a rich variety of fully stationary vortex structures, termed H-clusters, made of an increasing number of vortices nested in paraxial wave fields confined by trapping potentials. However, we show that the constituent vortices are globally linked, rather than products of independent vortices. Also, they always feature a monopolar global wave front and exist in nonlinear systems, such as Bose-Einstein condensates. Clusters with multipolar global wave fronts are non-stationary or at best flipping.Comment: 4 pages, 5 PostScript figure

Measurement of the rotational frequency shift imparted to a rotating light beam possessing orbital angular momentum

We observe the frequency shift, l Omega, imparted to a mm-wave beam with an orbital angular momentum of l (h) over bar per photon, when the beam,is rotated at angular frequency Omega. We show that this shift, and those found in a number of experiments on the rotation of circularly polarized beams, are special cases of the rotational frequency shift recently predicted by Bialynicki-Birula and Bialynicka-Birula. The measurement also explicitly confirms a theoretical prediction by Nienhuis

Rotational frequency shift of a light beam

We explain the rotational frequency shift of a light beam in classical terms and measure it using a mm-wave source. The shift is equal to the total angular momentum per photon multiplied by the angular velocity between the source and observer. This is analogous to the translational Doppler shift, which is equal to the momentum per photon multiplied by the translational velocity. We show that the shifts due to the spin and orbital angular momentum components of the light beam act in an additive way. [S0031-9007(98)07769-2]

Being a ‘good’ mother: Immigrant mothers of disabled children

In South Korea, disability and immigration are hidden and invisible phenomena. This article examines how immigrant mothers experience the intersection of immigrant status and mothering a disabled child. Through semi-structured interviews with 16 immigrant mothers, this study found that the values of Confucian familism regarding motherhood and gender roles influenced how these immigrant mothers behaved. The study also found that immigrant mothers faced multiple forms of stigma and discrimination as a result of negative socio-cultural views of disability and immigration. Therefore, the article suggests a need for inter-professional, anti-oppression work strategies to support immigrant mothers of disabled children, along with education for social workers about these issues