Bose-representation for a strongly coupled nonequilibrim fermionic superfluid in a time-dependent trap

Using the functional integral formulation of a nonequilibrium quantum many-body theory we develop a regular description of a Fermi system with a strong attractive interaction in the presence of an external time-dependent potential. In the strong coupling limit this fermionic system is equivalent to a noequilibrium dilute Bose gas of diatomic molecules. We also consider a nonequilibrim strongly coupled Bardeen-Cooper-Schrieffer (BCS) theory and show that it reduces to the full nonlinear time-dependent Gross-Pitaevski (GP) equation, which determines an evolution of the condensate wave function.Comment: RevTeX 4, 6 pages, 2 eps figure

Electron scattering in quantum wells subjected to an in-plane magnetic field

It is shown that the electron scattering by static defects, acoustic or optical phonons in quantum wells subjected to an in-plane magnetic field is asymmetric. The probability of scattering contains terms which are proportional to both the electron wave vector and the magnetic field components. The terms under study are caused by the lack of an inversion center in quantum wells due to structure or bulk inversion asymmetry although they are of pure diamagnetic origin. Such a magnetic field induced asymmetry of scattering can be responsible for a number of phenomena. In particular, the asymmetry of inelastic electron-phonon interaction leads to an electric current flow if only the electron gas is driven out of thermal equilibrium with the crystal lattice.Comment: 5 pages, 1 figur

Spontaneous spin textures in dipolar spinor condensates

We have mapped out a detailed phase diagram that shows the ground state structure of a spin-1 condensate with magnetic dipole-dipole interactions. We show that the interplay between the dipolar and the spin-exchange interactions induces a rich variety of quantum phases that exhibit spontaneous magnetic ordering in the form of intricate spin textures.Comment: 4.1 pages, 4 figure

Towards a microscopic theory of toroidal moments in bulk periodic crystals

We present a theoretical analysis of magnetic toroidal moments in periodic systems, in the limit in which the toroidal moments are caused by a time and space reversal symmetry breaking arrangement of localized magnetic dipole moments. We summarize the basic definitions for finite systems and address the question of how to generalize these definitions to the bulk periodic case. We define the toroidization as the toroidal moment per unit cell volume, and we show that periodic boundary conditions lead to a multivaluedness of the toroidization, which suggests that only differences in toroidization are meaningful observable quantities. Our analysis bears strong analogy to the modern theory of electric polarization in bulk periodic systems, but we also point out some important differences between the two cases. We then discuss the instructive example of a one-dimensional chain of magnetic moments, and we show how to properly calculate changes of the toroidization for this system. Finally, we evaluate and discuss the toroidization (in the local dipole limit) of four important example materials: BaNiF_4, LiCoPO_4, GaFeO_3, and BiFeO_3.Comment: replaced with final (published) version, which includes some changes in the text to improve the clarity of presentatio

ТВОРЧЕСКИЙ МЕТОД ВОПЛОЩЕНИЯ БИОГРАФИЧЕСКОГО ДИСКУРСА В ПРАКТИКАХ ХУДОЖЕСТВЕННОГО ТАНЦА (НА РУБЕЖЕ 20–21 ВЕКОВ)

The article explores ballet performances as a form of artistic dance which emerged in the context of “biographical deconstructionism” and as a new concept for the cultivation of documentation. Based on an analysis of preserved archival material, the author examines how at the waning of postmodern culture, the concept of a new ballet form called “biographical ballet” was invented by European dance critics. The article goes on to illuminate the features incorporated in this innovative form by investigating its structure and providing examples. The author concludes that memory is again becoming one of the main themes in contemporary culture. This “revival” determines the pivot of the choreographic theater to biographical discourse and the formation of a new creative approach of the choreographic theater. Implementing this approach, choreographers modify, accommodate, and incorporate in their performances the techniques and vehicles of new musicality, thick polylinguistic space, intertextuality, paratextuality, and dramaturgical fragmentation, while maintaining ballet’s optical dramaturgy as a basis.В статье анализируются балетные спектакли как практики художественного танца, возникшие в контексте культивирования таких феноменов как «биографический деконструктивизм» и новая документальность. В опоре на архивные материалы, автор рассматривает, как на исходе постмодерна европейской танцевальной критикой формулируется концепт новой балетной формы — «биографического балета», и выявляет через анализ структуры этой новой формы те элементы, которые были в нее инкорпорированы. Автор приходит к выводу, что «память», как возродившийся тематиз современной культуры, обуславливает поворот практики художественного танца к биографическому дискурсу и становление нового творческого метода хореографического театра, модифицирующего и осваивающего приемы новой музыкальности, насыщенной полиязычности, интер- и паратекстуальности, драматургической фрагментарности при сохранении балетной оптической драматургии

Field-asymmetric transverse magnetoresistance in a nonmagnetic quantum-size structure

A new phenomenon is observed experimentally in a heavily doped asymmetric quantum-size structure in a magnetic field parallel to the quantum-well layers - a transverse magnetoresistance which is asymmetric in the field (there can even be a change in sign) and is observed in the case that the structure has a built-in lateral electric field. A model of the effect is proposed. The observed asymmetry of the magnetoresistance is attributed to an additional current contribution that arises under nonequilibrium conditions and that is linear in the gradient of the electrochemical potential and proportional to the parameter characterizing the asymmetry of the spectrum with respect to the quasimomentum.Comment: 10 pages, 5 figures. For correspondence, mail to [email protected]