Gaussian ellipsoid model for confined polymer systems

Polymer systems in slab geometries are studied on the basis of the recently presented Gaussian Ellipsoid Model [J. Chem. Phys. 114, 7655 (2001)].The potential of the confining walls has an exponential shape. For homogeneous systems in thermodynamic equilibrium we discuss density, orientation and deformation profiles of the polymers close to the walls. For strongly segregated mixtures of polymer components A and B equilibrium profiles are studied near a planar interface separating A and B rich regions. Spinodal decomposition processes of the mixtures in the presence of neutral walls show upon strong confinement an increase of the lateral size of A and B rich domains and a slowing down of the demixing kinetics. These findings are in agreement with predictions from time dependent Ginzburg--Landau theory. In the case, where one wall periodically favors one of the two mixture components over the other, different equilibrium structures emerge and lead to different kinetic pathways of spinodal decomposition processes in such systems.Comment: 18 pages, 16 figures, submitted to J. Chem. Phy

Transfer and storage of qubits in the presence of decoherence

The effects of decoherence on the transfer and storage of coherent quantum states in hybrid systems are studied within the Caldeira-Leggett approach. In general, we find that a high transfer fidelity can be achieved even if the decoherence time is less than an order of magnitude larger than the transfer time, which is approximately half a Rabi period and determined by the qubit-qubit coupling strength. Finally, we apply our results to assess the feasibility of a hybrid quantum memory system, comprised of the hyperfine qubit states of an ultracold atomic Bose-Einstein condensate and the flux qubit of a SQUID.Comment: 6 pages of EPL2, 3 figure

Tunneling into a Fractional Quantum Hall System and the Infrared Catastrophe

We calculate the tunneling density of states of a two-dimensional interacting electron gas in a quantizing magnetic field. We show that the observed pseudogap in the density of states can be understood as the result of an infrared catastrophe in a noninteracting electron model. This catastrophe stems from the response of an electronic system to the potential produced by the abruptly added charge during a tunneling event. Our formalism can be applied at any filling factor without the use of Chern-Simons or composite fermion theory

Explorations of Respectability and Resistance in Constructions of Black Womanhood at HBCUs

Somewhere in her college experience she must have an opportunity to develop poise, to increase her self-esteem and to establish a sense of her worth and dignity as an individual. She must experience peace and beauty in her environment and she must be accorded the respect and courtesy, which is so lacking in her life on the outside. The education of the Negro woman should give her an opportunity to exhaust to the fullest her powers of expression and creativit