Maximum thickness of a two-dimensional trapped Bose system

The trapped Bose system can be regarded as two-dimensional if the thermal fluctuation energy is less than the lowest energy in the perpendicular direction. Under this assumption, we derive an expression for the maximum thickness of an effective two-dimensional trapped Bose system.Comment: 1 pages, 0 figure

Entropy production in phase field theories

Allen-Cahn (Ginzburg-Landau) dynamics for scalar fields with heat conduction is treated in rigid bodies using a non-equilibrium thermodynamic framework with weakly nonlocal internal variables. The entropy production and entropy flux is calculated with the classical method of irreversible thermodynamics by separating full divergences.Comment: 5 pages, no figure

Plasma Membrane Antigens Detected by Replica Techniques

Methods are introduced for in situ preparation of cell cultures grown on glass coverslips using the replica technique. Special equipment and handling procedures enabled us to prepare large-sized and stable replicas suitable for ultrastructural and immunocytochemical analysis of the different faces of the plasma membrane (PM): the extraplasmic surface (ES), the complementary extraplasmic (EF) and protoplasmic (PF) fracture face, and the protoplasmic surface (PS). Colloidal gold markers in combination with protein A and monospecific/monoclonal antibodies were used to identify virus-specific antigens at the ES of infected cells. Stereo replicas show a coincident location of gold-labeled virus antigens at the ES and structures visible at the EF as well as at the PS. In addition, the association of these antigens with cytoskeletal elements is demonstrated

Replica-Immunogold Technique Applied to Studies on Measles Virus Morphogenesis

The replica technique was applied to studies on the dynamic process of measles virus budding on infected HeLa cells. Virus structures were identified by labeling with anti-measles antibodies and protein A-gold. The combination of these two methods enabled us (1) to characterize the sequence of virus budding at the plasma membrane, (2) to localize virus structures on cytoskeletons of infected cells, and (3) to study the influence of Ca2+ ions on virus structures at the plasma membrane. Studies on platinum carbon surface replicas suggest that the process of virus budding is similar to the genesis of cellular microvilli. Replicas prepared from cytoskeletons of infected cells reveal a close association of budding virus with actin filaments composing the outer parts of the networks. Replicas of apical plasma membranes isolated from infected cells show the attachment of viral nucleocapsids to the protoplasmic membrane face of infected cells. These nucleocapsids are not present on membranes prepared from cells treated with calcium and the ionophore A23187. In addition viral cell surface antigens become randomly distributed on these cells. The data suggest that measles virus morphogenesis at the plasma membrane of cultured cells is dependent on the function of the cytoskeleton and may be influenced by Ca2+ ions

Thiol density dependent classical potential for methyl-thiol on a Au(111) surface

A new classical potential for methyl-thiol on a Au(111) surface has been developed using density functional theory electronic structure calculations. Energy surfaces between methyl-thiol and a gold surface were investigated in terms of symmetry sites and thiol density. Geometrical optimization was employed over all the configurations while minimum energy and thiol height were determined. Finally, a new interatomic potential has been generated as a function of thiol density, and applications to coarse-grained simulations are presented

Evolution of ground state and upper critical field in R(1-x)GdxNi2B2C (R = Lu, Y): Coexistence of superconductivity and spin-glass state

We report effects of local magnetic moment, Gd3+, doping (x =< 0.3) on superconducting and magnetic properties of the closely related Lu(1-x)GdxNi2B2C and Y(1-x)GdxNi2B2C series. The superconducting transition temperature decreases and the heat capacity jump associated with it drops rapidly with Gd-doping; qualitative changes with doping are also observed in the temperature-dependent upper critical field behavior, and a region of coexistence of superconductivity and spin-glass state is delineated on the x - T phase diagram. The evolution of superconducting properties can be understood within Abrikosov-Gor'kov theory of magnetic impurities in superconductors taking into account the paramagnetic effect on upper critical field with additional contributions particular for the family under study

Finite-Size Scaling in Two-Dimensional Superfluids

Using the $x-y$ model and a non-local updating scheme called cluster Monte Carlo, we calculate the superfluid density of a two dimensional superfluid on large-size square lattices $L \times L$ up to $400\times 400$. This technique allows us to approach temperatures close to the critical point, and by studying a wide range of $L$ values and applying finite-size scaling theory we are able to extract the critical properties of the system. We calculate the superfluid density and from that we extract the renormalization group beta function. We derive finite-size scaling expressions using the Kosterlitz-Thouless-Nelson Renormalization Group equations and show that they are in very good agreement with our numerical results. This allows us to extrapolate our results to the infinite-size limit. We also find that the universal discontinuity of the superfluid density at the critical temperature is in very good agreement with the Kosterlitz-Thouless-Nelson calculation and experiments.Comment: 13 pages, postscript fil

POD for optimal control of the Cahn-Hilliard system using spatially adapted snapshots

The present work considers the optimal control of a convective Cahn-Hilliard system, where the control enters through the velocity in the transport term. We prove the existence of a solution to the considered optimal control problem. For an efficient numerical solution, the expensive high-dimensional PDE systems are replaced by reduced-order models utilizing proper orthogonal decomposition (POD-ROM). The POD modes are computed from snapshots which are solutions of the governing equations which are discretized utilizing adaptive finite elements. The numerical tests show that the use of POD-ROM combined with spatially adapted snapshots leads to large speedup factors compared with a high-fidelity finite element optimization

Density-functionals not based on the electron gas: Local-density approximation for a Luttinger liquid

By shifting the reference system for the local-density approximation (LDA) from the electron gas to other model systems one obtains a new class of density functionals, which by design account for the correlations present in the chosen reference system. This strategy is illustrated by constructing an explicit LDA for the one-dimensional Hubbard model. While the traditional {\it ab initio} LDA is based on a Fermi liquid (the electron gas), this one is based on a Luttinger liquid. First applications to inhomogeneous Hubbard models, including one containing a localized impurity, are reported.Comment: 4 pages, 4 figures (final version, contains additional applications and discussion; accepted by Phys. Rev. Lett.

Quantum Counterfactuals and Locality

Stapp's counterfactual argument for quantum nonlocality based upon a Hardy entangled state is shown to be flawed. While he has correctly analyzed a particular framework using the method of consistent histories, there are alternative frameworks which do not support his argument. The framework dependence of quantum counterfactual arguments, with analogs in classical counterfactuals, vitiates the claim that nonlocal (superluminal) influences exist in the quantum world. Instead it shows that counterfactual arguments are of limited use for analyzing these questions.Comment: 8 pages, 1 PSTricks figur