A numerical study of confinement in compact QED

Compact U(1) lattice gauge theory in four dimensions is studied by means of an efficient algorithm which exploits the duality transformation properties of the model. We focus our attention onto the confining regime, considering the interquark potential and force, and the electric field induced by two infinitely heavy sources. We consider both the zero and finite temperature setting, and compare the theoretical predictions derived from the effective string model and the dual superconductor scenario to the numerical results.Comment: 31 pages, 16 eps figures; v2: references added; v3: footnote added, summation ranges in section 4 made explicit, version published in JHE

Supersymmetric null-surfaces

Single trace operators with the large R-charge in supersymmetric Yang-Mills theory correspond to the null-surfaces in $AdS_5\times S^5$. We argue that the moduli space of the null-surfaces is the space of contours in the super-Grassmanian parametrizing the complex $(2|2)$-dimensional subspaces of the complex $(4|4)$-dimensional space. The odd coordinates on this super-Grassmanian correspond to the fermionic degrees of freedom of the superstring.Comment: v4: added a reference to the earlier work; corrected the formula for the stabilizer of the BMN vacuum; added the discussion of the complex structure of the odd coordinates in Section 3.

Coherent States of SU(l,1)SU(l,1) groups

This work can be considered as a continuation of our previous one (J.Phys., 26 (1993) 313), in which an explicit form of coherent states (CS) for all SU(N) groups was constructed by means of representations on polynomials. Here we extend that approach to any SU(l,1) group and construct explicitly corresponding CS. The CS are parametrized by dots of a coset space, which is, in that particular case, the open complex ball $CD^{l}$. This space together with the projective space $CP^{l}$, which parametrizes CS of the SU(l+1) group, exhausts all complex spaces of constant curvature. Thus, both sets of CS provide a possibility for an explicit analysis of the quantization problem on all the spaces of constant curvature.Comment: 22 pages, to be published in "Journal of Physics A

Матеріали XIV Всеукраїнської науково-практичної конференції студентів, аспiрантiв та молодих вчених «Теоретичні i прикладні проблеми фізики, математики та інформатики»

Reactive joining of various materials by using different types of reactive multilayer foils is considered. An electron beam deposition method is presented for producing reactive composite foils. These foils may provide efficient joining of traditional PCBs.joining, welding, bonding, exothermic reaction, reactive multilayer foil, electron-beam deposition, microstructur

Study of the martensitic transformation in the Hafnium-Palladium system

High temperature shape memory alloys have received a large interest for many years but none of the systems studied so far has led to industrial applications. Those alloys are expected to develop an actuating role in high temperature environment as for example aircraft turbines. Lots of criteria are required in order to substitute or optimize heavy existing actuators. Here are presented a few results obtained with the system hafnium-palladium, not so documented for the moment, that develops a martensitic transformation at around 773 K. According to the characteristics of very well-known alloys such as NiTi, some compositions around the equiatomic are explored. The main ob jective of our work is to know the influence of a stoechiometry gap on the microstructure of the alloys and the martensitic transformation