Critical behavior of the compact 3d U(1) gauge theory on isotropic lattices

We report on the computation of the critical point of the deconfinement phase transition, critical indices and the string tension in the compact three dimensional U(1) lattice gauge theory at finite temperatures. The critical indices govern the behavior across the deconfinement phase transition in the pure gauge U(1) model and are generally expected to coincide with the critical indices of the two-dimensional XY model. We studied numerically the U(1) model for N_t=8 on lattices with spatial extension ranging from L=32 to L=256. Our determination of the infinite volume critical point on the lattice with N_t=8 differs substantially from the pseudo-critical coupling at L=32, found earlier in the literature and implicitly assumed as the onset value of the deconfined phase. The critical index $\nu$ computed from the scaling of the pseudo-critical couplings with the extension of the spatial lattice agrees well with the XY value $\nu$=1/2. On the other hand, the index $\eta$ shows large deviation from the expected universal value. The possible reasons of such behavior are discussed in details.Comment: 15 pages, 7 figures; version accepted for publication on J. Stat. Mech

Description and texts for the auxiliary programs for processing video information on the YeS computer. Part 3: Test program 2

The functions were discribed and the operating instructions, the block diagram and the proposed versions are given for modifying the program in order to obtain the statistical characteristics of multi-channel video information. The program implements certain man-machine methods for investigating video information. It permits representation of the material and its statistical characteristics in a form which is convenient for the user

Mass Gap, Abelian Dominance and Vortex Dynamics in SU(2) Spin Model

We discuss a new approach to the investigation of the nature of the mass gap in spin systems with continuous global symmetries which is much analogous to the method of abelian projection in the gauge theories. We suggest that the abelian degrees of freedom, in particular, abelian vortices are responsible for the mass gap generation phenomena in the non-abelian spin systems. To check our hypothesis we study numerically the three-dimensional SU(2) spin model in the Maximal Abelian projection. We find that the abelian mass gap in the projected theory coincides with the full non-abelian mass gap within numerical errors. The study of the percolation properties of the abelian vortex trajectories shows that the phase transition and the mass gap generation in the 3D SU(2) spin model are driven by the abelian vortex condensation.Comment: 12 pages, LaTeX, 4 figures, uses epsf.sty; Fig.3 is replaced and a few comments are adde

ARPES on HTSC: simplicity vs. complexity

A notable role in understanding of microscopic electronic properties of high temperature superconductors (HTSC) belongs to angle resolved photoemission spectroscopy (ARPES). This technique supplies a direct window into reciprocal space of solids: the momentum-energy space where quasiparticles (the electrons dressed in clouds of interactions) dwell. Any interaction in the electronic system, e.g. superconducting pairing, leads to modification of the quasi-particle spectrum--to redistribution of the spectral weight over the momentum-energy space probed by ARPES. A continued development of the technique had an effect that the picture seen through the ARPES window became clearer and sharper until the complexity of the electronic band structure of the cuprates had been resolved. Now, in an optimal for superconductivity doping range, the cuprates much resemble a normal metal with well predicted electronic structure, though with rather strong electron-electron interaction. This principal disentanglement of the complex physics from complex structure reduced the mystery of HTSC to a tangible problem of interaction responsible for quasi-particle formation. Here we present a short overview of resent ARPES results, which, we believe, denote a way to resolve the HTSC puzzle.Comment: A review written for a special issue of FN

Dissolved silicon and nitrogen in glacial rivers and water of Blago bay (Russian Arctic, Novaya Zemlya): origin, variability and spreading

Hydrochemical studies of watercourses and the water area of Blagopoluchia bay (Novaya Zemlya, Arctic, Russia) have been carried out. The concentrations of nutrients in rivers and streams are higher than those in the water area of Blagopoluchia bay. It is shown that the concentration of silicon in constantly flowing rivers is 1–13 μM, the concentration of NO3 — 0.5–8, for small and temporary streams these values are higher and are in the range of 18–46 μM Si, 1–11 μM NO3– . The influence of streams and rivers flowing into Blagopoluchia Bay on the water area of the bay is local and extends to 1 km from the mouth, and does not influence the Kara Sea nutrient content.Hydrochemical studies of watercourses and the water area of Blagopoluchia bay (Novaya Zemlya, Arctic, Russia) have been carried out. The concentrations of nutrients in rivers and streams are higher than those in the water area of Blagopoluchia bay. It is shown that the concentration of silicon in constantly flowing rivers is 1–13 μM, the concentration of NO3 — 0.5–8, for small and temporary streams these values are higher and are in the range of 18–46 μM Si, 1–11 μM NO3– . The influence of streams and rivers flowing into Blagopoluchia Bay on the water area of the bay is local and extends to 1 km from the mouth, and does not influence the Kara Sea nutrient content