Fluctuation induced conductivity of superconductors above the transition temperature: Regularization of the Maki diagram

The Maki contribution to the conductivity above the superconducting transition temperature is regularized within the framework of the BCS theory. This is achieved through the renormalization of the impurity scattering vertex by inclusion of the effects of pair fluctuations. The conductivity is evaluated for a thin film. It depends only on the reduced temperature and the normal resistance per square. Fair agreement is found with Al films over a wide temperature range. Agreement is not found with experiments on Bi, Pb and Ga films, which apparently contain a strong additional pair-breaking effect. The temperature range in which interactions among fluctuations become important in the Maki conductivity is generally larger than that given by the Ginzburg criterion

Photon statistics for threshold laser light with finite counting time

Correlations of intensity fluctuations for threshold laser light with finite counting time

Angular distributions of scattered excited muonic hydrogen atoms

Differential cross sections of the Coulomb deexcitation in the collisions of excited muonic hydrogen with the hydrogen atom have been studied for the first time. In the framework of the fully quantum-mechanical close-coupling approach both the differential cross sections for the $nl \to n'l'$ transitions and $l$-averaged differential cross sections have been calculated for exotic atom in the initial states with the principle quantum number $n=2 - 6$ at relative motion energies $E_{\rm {cm}}=0.01 - 15$ eV and at scattering angles $\theta_{\rm {cm}}=0 - 180^{\circ}$. The vacuum polarization shifts of the $ns$-states are taken into account. The calculated in the same approach differential cross sections of the elastic and Stark scattering are also presented. The main features of the calculated differential cross sections are discussed and a strong anisotropy of cross sections for the Coulomb deexcitation is predicted.Comment: 5 pages, 9 figure

ЭКСТРАКЦИОННО-ХРОМАТОГРАФИЧЕСКОЕ ОПРЕДЕЛЕНИЕ МЕСТНЫХ АНЕСТЕТИКОВ В ВОДНЫХ СРЕДАХ

The extraction novocaine, lidocaine anestezina are studied from aqueous media by individual organic solvents (aliphatic alcohols, normal and isomeric structure of C3 – C9 alkylacetates C2 – C5) and their mixtures using of different salting-out agents (chlorides, sulfates, sodium and ammonium). The coefficients of the distribution and the degree of extraction of anesthetics are calculated. It is shown that with increasing number of carbon atoms in the molecules of alcohols and esters their extractant possibility is decreased and alcohols isomers are less effective than normal ones. For the most complete extraction of the anesthetics the mixtures of alcohols with isomeric structure and alkyl acetates are used. Two and ternary-component mobile phase at chromatography in thin layer are studied for separation of local anesthetics in the concentrates, the mobility coefficients of substances are calculated. Quantitative evaluation are carried out by application of specialized software. The separation coefficients of anesthetics are calculated. The technique of determination of analytes in aqueous media is developed. The results of the extraction- chromatographic determination of novocaine, lidocaine and anaesthesin in aqueous media are proved by method «introduced – found». The range of detectable concentrations is 0.1 – 1 mkg/sm3, detection limit is 0.02 mkg/sm3. The relative error of determination is less than 10 %.Keywords: local anesthetics, extraction, chromatography in a thin layer(Russian)DOI: http://dx.doi.org/10.15826/analitika.2013.17.4.013Ia.I. Korenman, T.V. Chibisova, P.T. Sukhanov, M.V. Zybenko Federal State Budget Educational Institution of Higher Professional Education «Voronezh State University of Engineering Technologies» (FSBEI HPE «VSUET»), Voronezh, Russian Federation Изучена экстракция новокаина, лидокаина и анестезина из водных сред индивидуальными органическими растворителями (алифатические спирты нормального и изомерного строения С3 – С9, алкилацетаты С2 – С5) и смесями на их основе при применении хлоридов и сульфатов натрия и аммония. Рассчитаны коэффициенты распределения и степени извлечения анестетиков. С увеличением числа углеродных атомов в радикале спиртов и эфиров их экстрагирующая способность снижается, а также спирты-изомеры менее эффективны по сравнению с нормальными. Для наиболее полного извлечения анестетиков применены смеси, состоящие из спиртов изомерного строения и алкилацетатов. Изучены двух- и трехкомпонентные подвижные фазы при хроматографии в тонком слое для разделения местных анестетиков в концентратах, приведены коэффициенты подвижности веществ. Количественная оценка произведена при применении специализированного программного обеспечения. Разработана методика определения исследуемых веществ в водных средах. Диапазон определяемых концентраций от 0.1 до 1 мкг/см3, предел обнаружения  –0.02 мкг/см3. Относительная погрешность определения не превышает 10 %.Ключевые слова: местные анестетики, экстракция, хроматография в тонком слоеDOI: http://dx.doi.org/10.15826/analitika.2013.17.4.01

Influence of a Uniform Current on Collective Magnetization Dynamics in a Ferromagnetic Metal

We discuss the influence of a uniform current, $\vec{j}$, on the magnetization dynamics of a ferromagnetic metal. We find that the magnon energy $\epsilon(\vec{q})$ has a current-induced contribution proportional to $\vec{q}\cdot \vec{\cal J}$, where $\vec{\cal J}$ is the spin-current, and predict that collective dynamics will be more strongly damped at finite ${\vec j}$. We obtain similar results for models with and without local moment participation in the magnetic order. For transition metal ferromagnets, we estimate that the uniform magnetic state will be destabilized for $j \gtrsim 10^{9} {\rm A} {\rm cm}^{-2}$. We discuss the relationship of this effect to the spin-torque effects that alter magnetization dynamics in inhomogeneous magnetic systems.Comment: 12 pages, 2 figure

Quantum fields in disequilibrium: neutral scalar bosons with long-range, inhomogeneous perturbations

Using Schwinger's quantum action principle, dispersion relations are obtained for neutral scalar mesons interacting with bi-local sources. These relations are used as the basis of a method for representing the effect of interactions in the Gaussian approximation to field theory, and it is argued that a marked inhomogeneity, in space-time dependence of the sources, forces a discrete spectrum on the field. The development of such a system is characterized by features commonly associated with chaos and self-organization (localization by domain or cell formation). The Green functions play the role of an iterative map in phase space. Stable systems reside at the fixed points of the map. The present work can be applied to self-interacting theories by choosing suitable properties for the sources. Rapid transport leads to a second order phase transition and anomalous dispersion. Finally, it is shown that there is a compact representation of the non-equilibrium dynamics in terms of generalized chemical potentials, or equivalently as a pseudo-gauge theory, with an imaginary charge. This analogy shows, more clearly, how dissipation and entropy production are related to the source picture and transform a flip-flop like behaviour between two reservoirs into the Landau problem in a constant `magnetic field'. A summary of conventions and formalism is provided as a basis for future work.Comment: 23 pages revte

Chiral Anomaly and Spin Gap in One-Dimensional Interacting Fermions

Semiclassical approach has been developed for the one-dimensional interacting fermion systems. Starting from the incommensurate spin density wave (SDW) mean field state for the repulsive Hubbard model in 1D, the non-Abelian bosonized Lagrangian describing the spin-charge separation is obtained. The Berry phase term is derived from the chiral anomaly, and we obtain the massless Tomonaga-Luttinger liquid in the single chain case while the spin gap opens in the double-chain system. This approach offers a new method to identify the strong-coupling fixed point, and its relation to the Abelian bosonization formalism is discussed on the spin gap state. The generalization to higher dimensions is also discussed.Comment: Revised and enlarged version. 16 pages in REVTE

Macroscopic Quantum Tunneling of a Domain Wall in a Ferromagnetic Metal

The macroscopic quantum tunneling of a planar domain wall in a ferromagnetic metal is studied based on the Hubbard model. It is found that the ohmic dissipation is present even at zero temperature due to the gapless Stoner excitation, which is the crucial difference from the case of the insulating magnet. The dissipative effect is calculated as a function of width of the wall and is shown to be effective in a thin wall and in a weak ferromagnet. The results are discussed in the light of recent experiments on ferromagnets with strong anisotropy. PACS numbers:75.60.Ch, 03.65.Sq, 75.10.LpComment: 13page