Photon propagator,monopoles, and the thermal phase transition in three dimensional compact QED

We investigate the gauge boson propagator in the three dimensional compact Abelian gauge model in the Landau gauge at finite temperature. The presence of the monopole plasma in the confinement phase leads to the appearance of an anomalous dimension in the momentum dependence of the propagator. The anomalous dimension as well as an appropriate ratio of photon wave function renormalization constants with and without monopoles is observed to be an order parameter for the deconfinement phase transition. We discuss the relation between our results and the confining properties of the gluon propagator in non-Abelian gauge theories.     

Influence of Cyclodextrins on the Kinetics of Oxidation of Amino Acids and BSA by Hydrazyl Radicals

The kinetics of oxidation of amino acids (Arg, His, Lys, Phe, Thr and Tyr), a dipeptide (Gly-His), and BSA (bovine serum albumin) by two persistent water soluble free radicals of the hydrazyl type has been studied.The rate decreases in the order Arg>Lys>Tyr>Thr>HisBSAPheGly-His with bothfree radicals. Addition to the reaction mixture of - and -cyclodextrin decreases the oxidation rate, probably due to amino acidencapsulation in the cyclodextrin cavity. -Cyclodextrin protects more efficiently against oxidation than -cyclodextrin.     

Lattice vortices in the two-dimensional Abelian Higgs model

We generate and identify multi-vortices of the 2D Abelian Higgs model on a finite lattice by relaxation of Monte Carlo equilibrium configurations. The lattice vortices have action and a uniquely defined topological charge corresponding to the continuum ones. They exhibit the expected exponential decay behaviour and satisfy approximately the classical equations of motion. Vortex-antivortex superpositions are seen as well, supporting the dilute gas picture. Single vortices finally relax into “dislocations” and disappear. A background charge construction turns out nearly insensitive with respect to dislocations.     

The microscopic investigation of structures of moving flux lines by neutron and muon techniques

We have used a variety of microscopic techniques to reveal the structure and motion of flux line arrangements, when the flux lines in low T _c type II superconductors are caused to move by a transport current. Using small-angle neutron scattering by the flux line lattice (FLL), we are able to demonstrate directly the alignment by motion of the nearest-neighbor FLL direction. This tends to be parallel to the direction of flux line motion, as had been suspected from two-dimensional simulations. We also see the destruction of the ordered FLL by plastic flow and the bending of flux lines. Another technique that our collaboration has employed is the direct measurement of flux line motion, using the ultra-high-resolution spectroscopy of the neutron spin-echo technique to observe the energy change of neutrons diffracted by moving flux lines. The muon spin rotation (μSR) technique gives the distribution of values of magnetic field within the FLL. We have recently succeeded in performing μSR measurements while the FLL is moving. Such measurements give complementary information about the local speed and orientation of the FLL motion. We conclude by discussing the possible application of this technique to thin film superconductors.     

Investigation of the vacuum structure of the Georgi-Glashow model on the lattice

In this paper the BKS kernels of BRST bosonic strings are given. And from the kernels the relationships between geometric quantization and path integral quantization of bosonic strings with BRST symmetry are established. At the classical level, we also prove that the symplectic form in the phase space of bosonic strings is BRST invariant and nondegenerate.     

Electric field effects in sodium bis(2-ethylhexyl)sulfosuccinate water-in-oil microemulsions: field-induced percolation and dynamics of structural changes

We investigate the effect of high electric fields on the percolation behaviour of sodium bis(2-ethylhexyl)sulfosuccinate water-in-oil microemulsions in the L₂ phase and examine the existence of critical fields as a function of droplet radius and droplet concentration. It is shown that there is no direct correlation with critical fields as discussed for electrorheological fluids. Very low critical fields are found in certain ranges of droplet radii. Clustering of droplets with material exchange may be postulated under these conditions. Received: 29 July 1999/Accepted: 8 February 2000