Quantum Hall Bilayer as Pseudospin Magnet

We revisit the physics of electron gas bilayers in the quantum Hall regime [Nature, 432 (2004) 691; Science, 305 (2004) 950], where transport and tunneling measurements provided evidence of a superfluid phase being present in the system. Previously, this behavior was explained by the possible formation of a BEC of excitons in the half-filled electron bilayers, where empty states play the role of holes. We discuss the fundamental difficulties with this scenario, and propose an alternative approach based on a treatment of the system as a pseudospin magnet. We show that the experimentally observed tunneling peak can be linked to the XY ferromagnet (FM) to Ising antiferromagnet (AFM) phase transition of the S=1/2 XXZ pseudospin model, driven by the change in total electron density. This transition is accompanied by a qualitative change in the nature of the low energy spin wave dispersion from a gapless linear mode in the XY-FM phase to a gapped, quadratic mode in the Ising-AFM phase.Comment: 5 pages, 4 figures; corrected and close to printed versio

The triglyceride composition ofMoringa concanensis seed fat

Moringa concanensis seed fat and its randomized product have been subjected to pancreatic hydrolysis. Glyceride compositions have been calculated from the original fatty acid composition and those of the monoglycerides produced by hydrolysis. The per cent GS3 content of the interesterified product has also been determined by the combined techniques of thin layer chromatography on silver nitrate impregnated silica gel and colorimetry.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141952/1/lipd0666.pd

Topological Confinement and Superconductivity

We derive a Kondo Lattice model with a correlated conduction band from a two-band Hubbard Hamiltonian. This mapping allows us to describe the emergence of a robust pairing mechanism in a model that only contains repulsive interactions. The mechanism is due to topological confinement and results from the interplay between antiferromagnetism and delocalization. By using Density-Matrix-Renormalization-Group (DMRG), we demonstrate that this mechanism leads to dominant superconducting correlations in a 1D-system.Comment: 4 pages, 4 figure

Langevin Dynamics simulations of a 2-dimensional colloidal crystal under confinement and shear

Langevin Dynamics simulations are used to study the effect of shear on a two-dimensional colloidal crystal confined by structured parallel walls. When walls are sheared very slowly, only two or three crystalline layers next to the walls move along with them, while the inner layers of the crystal are only slightly tilted. At higher shear velocities, this inner part of the crystal breaks into several pieces with different orientations. The velocity profile across the slit is reminiscent of shear-banding in flowing soft materials, where liquid and solid regions coexist; the difference, however, is that in the latter case the solid regions are glassy while here they are crystalline. At even higher shear velocities, the effect of the shearing becomes smaller again. Also the effective temperature near the walls (deduced from the velocity distributions of the particles) decreases again when the wall velocity gets very large. When the walls are placed closer together, thereby introducing a misfit, a structure containing a soliton staircase arises in simulations without shear. Introducing shear increases the disorder in these systems until no solitons are visible any more. Instead, similar structures like in the case without misfit result. At high shear rates, configurations where the incommensurability of the crystalline structure is compensated by the creation of holes become relevant

Electrochemically Initiated Copolymerization of Acrylamide with Acrylic Acid & Methacrylic Acid

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Behavior interpretation from traffic video streams

Copyright © 2003 IEEEThis paper considers video surveillance research applied to traffic video streams. We present a framework for analyzing and recognizing different possible behaviors from image sequences acquired from a fixed camera. Two types of interactions have been mainly considered. In one there is interaction between two or more mobile objects in the field of view (FOV) of the camera. The other is interaction between a mobile object and static objects in the environment. The framework is based on two types of a priori knowledge: (1) the contextual knowledge of the camera's FOV, in terms of the description of the different static objects of the scene and (2) sets of predefined behaviors which need to be analyzed in different contexts. At present the system is designed to recognize behavior from stored videos and retrieve the frames in which the specific behaviors took place. We demonstrate successful behavior recognition results for pedestrian-vehicle interaction and vehicle-checkpost interactions