Transport properties of single channel quantum wires with an impurity: Influence of finite length and temperature on average current and noise

The inhomogeneous Tomonaga Luttinger liquid model describing an interacting quantum wire adiabatically coupled to non-interacting leads is analyzed in the presence of a weak impurity within the wire. Due to strong electronic correlations in the wire, the effects of impurity backscattering, finite bias, finite temperature, and finite length lead to characteristic non-monotonic parameter dependencies of the average current. We discuss oscillations of the non-linear current voltage characteristics that arise due to reflections of plasmon modes at the impurity and quasi Andreev reflections at the contacts, and show how these oscillations are washed out by decoherence at finite temperature. Furthermore, the finite frequency current noise is investigated in detail. We find that the effective charge extracted in the shot noise regime in the weak backscattering limit decisively depends on the noise frequency $\omega$ relative to $v_F/gL$, where $v_F$ is the Fermi velocity, $g$ the Tomonaga Luttinger interaction parameter, and $L$ the length of the wire. The interplay of finite bias, finite temperature, and finite length yields rich structure in the noise spectrum which crucially depends on the electron-electron interaction. In particular, the excess noise, defined as the change of the noise due to the applied voltage, can become negative and is non-vanishing even for noise frequencies larger than the applied voltage, which are signatures of correlation effects.Comment: 28 pages, 19 figures, published version with minor change

Fractional charge in transport through a 1D correlated insulator of finite length

Transport through a one channel wire of length $L$ confined between two leads is examined when the 1D electron system has an energy gap $2M$: $M > T_L \equiv v_c/L$ induced by the interaction in charge mode ($v_c$: charge velocity in the wire). In spinless case the transformation of the leads electrons into the charge density wave solitons of fractional charge $q$ entails a non-trivial low energy crossover from the Fermi liquid behavior below the crossover energy $T_x \propto \sqrt{T_L M} e^{-M /[T_L(1-q^2)]}$ to the insulator one with the fractional charge in current vs. voltage, conductance vs. temperature, and in shot noise. Similar behavior is predicted for the Mott insulator of filling factor $\nu = integer/(2 m')$.Comment: 5 twocolumn pages in RevTex, no figure

Threshold features in transport through a 1D constriction

Suppression of electron current $\Delta I$ through a 1D channel of length $L$ connecting two Fermi liquid reservoirs is studied taking into account the Umklapp electron-electron interaction induced by a periodic potential. This interaction causes Hubbard gaps $E_H$ for $L \to \infty$. In the perturbative regime where $E_H \ll v_c/L$ ($v_c:$ charge velocity), and for small deviations $\delta n$ of the electron density from its commensurate values $- \Delta I/V$ can diverge with some exponent as voltage or temperature $V,T$ decreases above $E_c=max(v_c/L,v_c \delta n)$, while it goes to zero below $E_c$. This results in a nonmonotonous behavior of the conductance.Comment: Final variant published in PRL, 79, 1714; minor correction

German Youth Language: Word-Formation Types of Suffix Nouns and Their Semantic Relations

The article is devoted to the study of word-formation types in modern German youth slang and a description of their systemic paradigmatic relations. The research material was a large group of suffix nouns, presented in the dictionaries of youth slang, as well as on youth literature sites. The suffix nouns formed by the word-formation type “producing basis + suffix” are analyzed in the article. The deep connections of motivating and motivated units are revealed, which reflect the logic of the connections of objects of reality in the linguistic consciousness, and the implementation of these relations in word-formation types is also traced. As a result of the analysis of word-formation meanings in the group of German nouns, which are youth slangisms constructed according to the “base + suffix” model, 4 main word-formation types were identified. The analysis proves that the thematic associations of the same word-formation type are in a variety of paradigmatic relationships, which at the lexical level are manifested in the form of synonymy, hypo- and hyperonymy, antonymy and polysemy. The word-formation types of suffix nouns studied in this work allowed to conclude that the intra-type and inter-type semantic relations are manifested most variably in the lexical-semantic field “Human designation”

Using an Autograft from the Fibula Diaphysis in the Surgical Treatment of Patients with Fractures of the Proximal Humerus on the Background of Critical Osteoporosis

The frequency of unsatisfactory results of surgical treatment of patients with a fracture of the proximal humerus remains high and is up to 40 %. This is primarily due to the early instability of the metal structure against the background of osteoporosis and as a consequence of non-fusion of the fracture and the formation  of a false joint. The aim of the study was to evaluate the effectiveness and safety of a new surgical method for treating patients with a fracture of the proximal humerus against the background of critical osteoporosis. After the approval of the local ethics Committee, 2 groups of 10 patients were formed in the clinic: the patients of  main group were operated by the proposed method; the group of clinical comparison was operated by the standard method. In all clinical cases, fractures of the proximal humerus were consolidated on control radiographs. VAS assessment the pain syndrome in the early postoperative period showed that there were no  statistically significant differences in the shoulder joint area in the groups. Three months after surgery, when assessing the volume of movement in the shoulder joint (without the participation of the scapula), there was a statistically significant improvement in the main group: abduction – by 35° and external  rotation – by 25° (p<0.05). When assessing the range of motion of the operated shoulder joint using the ASES scale, a  statistically significant improvement was observed in the main group by 11.6 points after 3 months after  surgery. According to the assessment of the patient›s functional recovery according to the DASH scale, the indicators in the main group were statistically significantly better, which indicates a complete recovery of the shoulder joint function. Thus, the use of the proposed new method, in comparison with other known technologies for surgical treatment of fractures of the proximal humerus, allows achieving a more rigid and stable fixation of bone fragments in the aftermath of trauma and the presence of regional osteoporosis

Using a New Method for Preparing an Autograft for Anterior Cruciate Ligament Plasty

Background. Currently, work continues to improve the methods of arthroscopic reconstruction of the anterior cruciate ligament with an autograft, aimed at reducing the risk of postoperative failure.Aim of the study. To assess the immediate results of using a new method of preparing an autograft for anterior cruciate ligament plasty.Materials and methods. The analysis of the results of surgical treatment of 28 patients with old complete traumatic rupture of the anterior cruciate ligament, who were treated in the Department of traumatology and orthopedics of the Irkutsk Scientific Center of Surgery and Traumatology, was carried out. The patients were men aged 18 to 40 years. The common thing for all patients was the All-inside arthroscopic plasty of the anterior cruciate ligament. Two groups of patients were formed depending on the method of preparation of the autograft. The first group consisted of 18 patients in whom a well-known technique was used, including the formation of a four-bundle autograft from one tendon of the semitendinosus muscle. In 10 patients of the second group, a new method of preparing an autograft was used, including the stage of preliminary determination of the required length and thickness of the autograft, and the stage of forming an autograft from the tendon of the semitendinosus and gracilis muscles on the common tendon pedicle.Results. Comparative analysis of the immediate results of arthroscopic plasty of the anterior cruciate ligament with an autograft in case of its old complete traumatic injury revealed a significantly lower number of undesirable consequences when using a new method of preparing an autograft. In two cases, persistence of  the pain syndrome associated with arthritic changes in the joint was observed, in one patient there was a  restriction of movements in the knee joint, no synovitis, a sensation of instability of the knee joint, ruptures  and detachments of the autograft were found. All patients were satisfied with the achieved result.Conclusion. A new method of preparing an autograft for plasty of the anterior cruciate ligament allows  achieving anatomical reconstruction of the anterior cruciate ligament, optimal function of the knee joint,  reducing pain, significantly reducing the risk of developing knee instability, ruptures and abruptions of the autograft in the postoperative period due to an individual approach, increasing the strength of the autograft and the strength of its fixation in the bone canals

Current Helicity and Twist as Two Indicators of The Mirror Asymmetry of solar Magnetic Fields

A comparison between the two tracers of magnetic field mirror asymmetry in solar active regions, twist and current helicity, is presented. It is shown that for individual active regions these tracers do not possess visible similarity while averaging by time over the solar cycle, or by latitude, reveals similarities in their behaviour. The main property of the dataset is anti-symmetry over the solar equator. Considering the evolution of helical properties over the solar cycle we find signatures of a possible sign change at the beginning of the cycle, though more systematic observational data are required for a definite confirmation. We discuss the role of both tracers in the context of the solar dynamo theory.Comment: 14 pages, 6 figure

Electron transport through a mesoscopic metal-CDW-metal junction

In this work we study the transport properties of a finite Peierls-Fr\"ohlich dielectric with a charge density wave of the commensurate type. We show that at low temperatures this problem can be mapped onto a problem of fractional charge transport through a finite-length correlated dielectric, recently studied by Ponomarenko and Nagaosa [Phys. Rev. Lett {\bf 81}, 2304 (1998)]. The temperature dependence of conductance of the charge density wave junction is presented for a wide range of temperatures.Comment: Latex, Revtex 3.0, 7 pages, 2 EPS figures (uses epfs