BRST approach to Lagrangian formulation of bosonic totally antisymmeric tensor fields in curved space

We apply the BRST approach, previously developed for higher spin field theories, to gauge invariant Lagrangian construction for antisymmetric massive and massless bosonic fields in arbitrary d-dimensional curved space. The obtained theories are reducible gauge models both in massless and massive cases and the order of reducibility grows with the value of the rank of the antisymmetric field. In both the cases the Lagrangians contain the sets of auxiliary fields and possess more rich gauge symmetry in comparison with standard Lagrangian formulation for the antisymmetric fields. This serves additional demonstration of universality of the BRST approach for Lagrangian constructions in various field models.Comment: 12 page

Coulomb blockade in quantum dots under AC pumping

We study conductance through a quantum dot under Coulomb blockade conditions in the presence of an external periodic perturbation. The stationary state is determined by the balance between the heating of the dot electrons by the perturbation and cooling. We analyze two cooling mechanisms: electron exchange with the cold contacts and emission of phonons. Together with the usual linear Ohmic heating of the dot electrons we consider possible effects of dynamic localization. The combination of the abovementioned factors may result in a drastic change of the shape of the Coulomb blockade peak with respect to the usual equilibrium one.Comment: 12 pages, 8 figure

Conformal self-dual fields

Conformal self-dual fields in flat space-time of even dimension greater than or equal to four are studied. Ordinary-derivative formulation of such fields is developed. Gauge invariant Lagrangian with conventional kinetic terms and corresponding gauge transformations are obtained. Gauge symmetries are realized by involving the Stueckelberg fields. Realization of global conformal symmetries is obtained. Light-cone gauge Lagrangian is found. Also, we demonstrate use of the light-cone gauge for counting of on-shell degrees of freedom of the conformal self-dual fields.Comment: 28 pages, LaTeX-2e, v3: Discussion of realization of conformal algebra symmetries on field strengths added to Sections 3,5. Appendices B,C,D and one reference added. Typos correcte

Proximity-induced superconductivity in graphene

We propose a way of making graphene superconductive by putting on it small superconductive islands which cover a tiny fraction of graphene area. We show that the critical temperature, T_c, can reach several Kelvins at the experimentally accessible range of parameters. At low temperatures, T<<T_c, and zero magnetic field, the density of states is characterized by a small gap E_g<T_c resulting from the collective proximity effect. Transverse magnetic field H_g(T) E_g is expected to destroy the spectral gap driving graphene layer to a kind of a superconductive glass state. Melting of the glass state into a metal occurs at a higher field H_{g2}(T).Comment: 4 pages, 3 figure

Mesoscopic fluctuations of the supercurrent in diffusive Josephson junctions

We study mesoscopic fluctuations and weak localization correction to the supercurrent in Josephson junctions with coherent diffusive electron dynamics in the normal part. Two kinds of junctions are considered: a chaotic dot coupled to superconductors by tunnel barriers and a diffusive junction with transparent normal--superconducting interfaces. The amplitude of current fluctuations and the weak localization correction to the average current are calculated as functions of the ratio between the superconducting gap and the electron dwell energy, temperature, and superconducting phase difference across the junction. Technically, fluctuations on top of the spatially inhomogeneous proximity effect in the normal region are described by the replicated version of the \sigma-model. For the case of diffusive junctions with transparent interfaces, the magnitude of mesoscopic fluctuations of the critical current appears to be nearly 3 times larger than the prediction of the previous theory which did not take the proximity effect into account.Comment: 19 pages, 14 figures, 2 table

Modern approaches to pharmacotherapy of chronic gastritis

The definition of gastritis is based on the histological features of the gastric mucosa. This is not the erythema observed during gastroscopy, and there are no specific clinical manifestations or symptoms that determine it. The modern classification of gastritis is based on time (acute and chronic), histological features, anatomical distribution and the main pathological mechanisms. Acute gastritis will develop into chronic if left untreated. Helicobacter pylori (H. pylori) is the most common cause of gastritis worldwide. However, from 60 to 70% H. pylori-negative subjects with functional dyspepsia or non-erosive gastroesophageal reflux were also found to have gastritis. H. pylori-negative gastritis is considered when a person meets all four of these criteria: negative triple staining of biopsies of the gastric mucosa, no history of treatment of H. pylori. In these patients, the cause of gastritis may be associated with tobacco smoking, alcohol consumption and / or the use of nonsteroidal anti-inflammatory drugs (NSAIDs) or steroids. Other causes of gastritis include autoimmune gastritis associated with antibodies of serum anti-parietal and anti-internal factor; organisms other than H. pylori, such as Mycobacterium avium intracellulare, Herpes simplex and Cytomegalovirus; gastritis caused by acid reflux; Rare causes of gastritis include collagen gastritis, sarcoidosis, eosinophilic gastritis and lymphocytic gastritis. The clinical picture, laboratory studies, gastroscopy, as well as histological and microbiological examination of tissue biopsies are important for the diagnosis of gastritis and its causes. Treatment of gastritis caused by H. pylori leads to the rapid disappearance of polymorphic-nuclear infiltration and a decrease in chronic inflammatory infiltrate with gradual normalization of the mucous membrane. Other types of gastritis should be treated based on their etiology

Magnetostimulated Chandges of Microhardness in Potassium Acid Phthalate Crystals

A decrease in microhardness along the (010) cleavage in potassium acid phthalate single crystals by 15--18% after the application of a permanent magnetic field was revealed for the first time. It is shown that the effect revealed is of the volume character. The role of interlayer water in the processes stimulated by a magnetic field is studied., Interlayer water plays does not cause the observed changes it only plays the part of an indicator of these changes in potassium acid phthalate crystals in a magnetic field. It is established that microhardness in the (100) plane of the crystal in an applied a magnetic field first increases by 12--15% and then remains constant in time within the accuracy of the experiment. The possibility of varying the crystal structure of potassium acid phthalate crystals by applying magnetic fields inducing rearrangement in the system of hydrogen bonds or in the defect structure is discussed.Comment: 6 pages, 7 figure

Keldysh action for disordered superconductors

Keldysh representation of the functional integral for the interacting electron system with disorder is used to derive microscopically an effective action for dirty superconductors. In the most general case this action is a functional of the 8 x 8 matrix Q(t,t') which depends on two time variables, and on the fluctuating order parameter field and electric potential. We show that this approach reproduces, without the use of the replica trick, the well-known result for the Coulomb-induced renormalization of the electron-electron coupling constant in the Cooper channel. Turning to the new results, we calculate the effects of the Coulomb interaction upon: i) the subgap Andreev conductance between superconductor and 2D dirty normal metal, and ii) the Josephson proximity coupling between superconductive islands via such a metal. These quantities are shown to be strongly suppressed by the Coulomb interaction at sufficiently low temperatures due to both zero-bias anomaly in the density of states and disorder-enhanced repulsion in the Cooper channel.Comment: RevTeX; 39 pages + 10 EPS figure

6d conformal gravity

In the framework of ordinary-derivative approach, conformal gravity in space-time of dimension six is studied. The field content, in addition to conformal graviton field, includes two auxiliary rank-2 symmetric tensor fields, two Stueckelberg vector fields and one Stueckelberg scalar field. Gauge invariant Lagrangian with conventional kinetic terms and the corresponding gauge transformations are obtained. One of the rank-2 tensor fields and the scalar field have canonical conformal dimension. With respect to these fields, the Lagrangian contains, in addition to other terms, a cubic potential. Gauging away the Stueckelberg fields and excluding the auxiliary fields via equations of motion, the higher-derivative Lagrangian of 6d conformal gravity is obtained. The higher derivative Lagrangian involves quadratic and cubic curvature terms. This higher-derivative Lagrangian coincides with the simplest Weyl invariant density discussed in the earlier literature. Generalization of de Donder gauge conditions to 6d conformal fields is also obtained.Comment: 31 pages, LaTeX-2e, v3: Footnotes 8,9,13, clarifying remark below Eq.(2.30), and references added. Misprints correcte