Renormalization of the Periodic Scalar Field Theory by Polchinski's Renormalization Group Method

The renormalization group (RG) flow for the two-dimensional sine-Gordon model is determined by means of Polchinski's RG equation at next-to-leading order in the derivative expansion. In this work we have two different goals, (i) to consider the renormalization scheme-dependence of Polchinski's method by matching Polchinski's equation with the Wegner-Houghton equation and with the real space RG equations for the two-dimensional dilute Coulomb-gas, (ii) to go beyond the local potential approximation in the gradient expansion in order to clarify the supposed role of the field-dependent wave-function renormalization. The well-known Coleman fixed point of the sine-Gordon model is recovered after linearization, whereas the flow exhibits strong dependence on the choice of the renormalization scheme when non-linear terms are kept. The RG flow is compared to those obtained in the Wegner-Houghton approach and in the dilute gas approximation for the two-dimensional Coulomb-gas.Comment: 14 pages, LaTeX, 1 figure; J. Phys. G (in press

Renormalization-Group Analysis of the Generalized sine-Gordon Model and of the Coulomb Gas for d >= 3 Dimensions

Renormalization-group (RG) flow equations have been derived for the generalized sine-Gordon model (GSGM) and the Coulomb gas (CG) in d >= 3 of dimensions by means of Wegner's and Houghton's, and by way of the real-space RG approaches. The UV scaling laws determined by the leading-order terms of the flow equations are in qualitative agreement for all dimensions d >= 3, independent of the dimensionality, and in sharp contrast to the special case d = 2. For the 4-dimensional GSGM it is demonstrated explicitly (by numerical calculations), that the blocked potential tends to a constant effective potential in the infrared (IR) limit, satisfying the requirements of periodicity and convexity. The comparison of the RG flows for the three-dimensional GSGM, the CG, and the vortex-loop gas reveals a significant dependence on the renormalization schemes and the approximations used.Comment: 19 pages, 8 figure

On the applicability of the layered sine-Gordon model for Josephson-coupled high-T_c layered superconductors

We find a mapping of the layered sine-Gordon model to an equivalent gas of topological excitations and determine the long-range interaction potentials of the topological defects. This enables us to make a detailed comparison to the so-called layered vortex gas, which can be obtained from the layered Ginzburg-Landau model. The layered sine-Gordon model has been proposed in the literature as a candidate field-theoretical model for Josephson-coupled high-T_c superconductors, and the implications of our analysis for the applicability of the layered sine-Gordon model to high-T_c superconductors are discussed. We are led to the conjecture that the layered sine--Gordon and the layered vortex gas models belong to different universality classes. The determination of the critical temperature of the layered sine-Gordon model is based on a renormalization-group analysis.Comment: 7 pages, accepted for publication in J. Phys.: Condens. Matte

Differential effect of a distractor on primary saccades and perceptual localization

AbstractA distractor presented nearby the target of a goal-directed short latency saccade leads to spatial averaging, that is, the saccade lands between the target and the distractor. This so-called global effect is a characteristic feature of the spatial processing underlying the programming of saccadic eye movements. To determine whether this effect of near distractors on saccade metrics is also reflected in perceptual localization, subjects performed a saccade task and a perceptual localization task using identical, briefly flashed visual stimuli. To make the available visual processing time for saccades and perception more similar, we followed the target with a mask.Without the mask, primary saccades with short latency landed between target and distractor. The distractor had less effect on primary saccades with longer latencies (>200 ms) and did not affect the final eye position after late secondary saccades in the dark. This indicates that the oculomotor system can correctly use information about the target location 200 ms after the target flash even if no visual stimulus is present during this period. Likewise the presence of a distractor did not affect perceptual localization.Under the masking condition a similar global effect occurred for primary saccades with short latencies, but the latency dependence of the global effect was weakened. Secondary saccades and perceptual localization still did not show a global effect. The results suggest that the primary saccade is based on a specific target acquisition process that differs from that used for spatial perception and for the programming of memory-guided corrective saccades

Interplay of fixed points in scalar models

We performed the renormalization group analysis of scalar models exhibiting spontaneous symmetry breaking. It is shown that an infrared fixed point appears in the broken symmetric phase of the models, which induces a dynamical scale, that can be identified with the correlation length. This enables one to identify the type of the phase transition which shows similarity to the one appearing in the crossover scale. The critical exponent $\nu$ of the correlation length also proved to be equal in the crossover and the infrared scaling regimes.Comment: 11 pages, 4 figure

Towards Contextual Action Recognition and Target Localization with Active Allocation of Attention

Exploratory gaze movements are fundamental for gathering the most relevant information regarding the partner during social interactions. We have designed and implemented a system for dynamic attention allocation which is able to actively control gaze movements during a visual action recognition task. During the observation of a partners reaching movement, the robot is able to contextually estimate the goal position of the partner hand and the location in space of the candidate targets, while moving its gaze around with the purpose of optimizing the gathering of information relevant for the task. Experimental results on a simulated environment show that active gaze control provides a relevant advantage with respect to typical passive observation, both in term of estimation precision and of time required for action recognition. © 2012 Springer-Verlag

Quantum Hall Resistance Overshoot in 2-Dimensional Electron Gases - Theory and Experiment

We present a systematical experimental investigation of an unusual transport phenomenon observed in two dimensional electron gases in Si/SiGe heterostructures under integer quantum Hall effect (IQHE) conditions. This phenomenon emerges under specific experimental conditions and in different material systems. It is commonly referred to as Hall resistance overshoot, however, lacks a consistent explanation so far. Based on our experimental findings we are able to develop a model that accounts for all of our observations in the framework of a screening theory for the IQHE. Within this model the origin of the overshoot is attributed to a transport regime where current is confined to co-existing evanescent incompressible strips of different filling factors.Comment: 26 pages, 10 figure

Проєкт будівництва 10-ти поверхового житлового будинку у місті Дніпро

Кваліфікаційна робота: 54 с., 5 табл., 6 Рисунок , 3 дод., 30 джерел. ЖИТЛОВИЙ БУДИНОК, ПАЛЬОВИЙ ФЦНДАМЕНТ, ПРОЕКТУВАННЯ, ТЕХНОЛОГІЯ І ОРГАНІЗАЦІЯ РОБІТ. Об’єкт роботи – багатоповерховий житловий будинок в м. Дніпро Мета роботи – запроектувати багатоквартирний житловий будинок . Результати. Обрані та обґрунтовані основні об’ємно-планувальні та конструктивні рішення. Виконане компонування конструктивної схеми, збір та розрахунок навантажень. Проведено розрахунок пальово-стрічкового фундаменту. Обрана раціональна схема суміщення технологічних процесів. Розроблено проект виконання робіт та відповідні технологічні карти. Виконано аналіз перспектив влаштування паль по імпульсній технології при будівництві багатоповерхових житлових будинків. Взаємозв’язок з іншими роботами – продовження інноваційної діяльності кафедри будівництва, геотехніки і геомеханіки НТУ «Дніпровська політехніка» в сфері будівництва та цивільної інженерії. Сфера застосування – технології спорудження об’єктів цивільного будівництва. Практичне значення роботи – підвищення техніко-економічних та культурно-соціальних аспектів цивільного будівництва.Qualification work: 54 pp., 4 tables, 6 Figure, 3 addition, 30 sources. RESIDENTIAL BUILDING, PILE FOUNDATION, DESIGN, TECHNOLOGY AND WORK ORGANIZATION. The object of work is a multistory residential building in Dnipro The purpose of the work is to design an apartment building. Results. Selected and substantiated the main spatial planning and design solutions. Completed layout of the structural scheme, collection and calculation of loads. The calculation of the pile-strip foundation was carried out. The rational scheme of combination of technological processes was chosen. The project of performance of works and the corresponding technological maps was developed. The analysis of prospects of arrangement of piles on pulse technology at construction of multistory apartment building was executed. Interconnection with other works - continuation of innovative activities of the Department of Construction, Geotechnics and Geomechanics of NTU " Dniprovs’ka Polytechnicа" in the field of construction and civil engineering. Scope - technologies of construction of civil engineering objects. The practical significance of the work is to increase the technical, economic and cultural and social aspects of civil engineering

Renormalization of composite operators

The blocked composite operators are defined in the one-component Euclidean scalar field theory, and shown to generate a linear transformation of the operators, the operator mixing. This transformation allows us to introduce the parallel transport of the operators along the RG trajectory. The connection on this one-dimensional manifold governs the scale evolution of the operator mixing. It is shown that the solution of the eigenvalue problem of the connection gives the various scaling regimes and the relevant operators there. The relation to perturbative renormalization is also discussed in the framework of the $\phi^3$ theory in dimension $d=6$.Comment: 24 pages, revtex (accepted by Phys. Rev. D), changes in introduction and summar