Metal-insulator transition and magnetism in correlated band insulator: FeSi and Fe1−x_{1-x}Cox_{x}Si

The LDA+DMFT (local density approximation combined with dynamical mean-field theory) computation scheme has been used to study spectral and magnetic properties of FeSi and Fe$_{1-x}$Co$_{x}$Si. Having compared different models we conclude that a correlated band insulator scenario in contrast to Kondo insulator model agrees with FeSi band structure as well as experimental data. Coulomb correlation effects lead to band narrowing of the states near the Fermi level with mass renormalization parameter $m^*\approx 2$ in agreement with the results of angle-resolved photoemission spectroscopy (ARPES). Temperature dependence of spectral functions and magnetic susceptibility calculated in DMFT reproduces transition from nonmagnetic semiconductor to metal with local magnetic moments observed experimentally. Cobalt doping leads to ferromagnetism that has itinerant nature and can be successfully described by LDA+DMFT method.Comment: 10 pages, 15 figure

Metal-Insulator Transitions and Magnetism in Correlated Band Insulators: FeSi and Fe1-x CoxSi

The LDA+DMFT (local density approximation combined with dynamical mean-field theory) computation scheme has been used to study spectral and magnetic properties of FeSi and Fe1-x Cox Si. Having compared different models, we conclude that a correlated band insulator scenario in contrast to Kondo insulator model agrees well with FeSi band structure and experimental data. Coulomb correlation effects lead to band narrowing of the states near the Fermi level with mass renormalization parameter m *≈.2 in agreement with the results of angle-resolved photoemission spectroscopy. Temperature dependence of spectral functions and magnetic susceptibility calculated in DMFT reproduces transition from nonmagnetic semiconductor to metal with local magnetic moments observed experimentally. Cobalt doping leads to ferromagnetism that has itinerant nature and can be successfully described by the LDA+DMFT method. © 2010 The American Physical Society.The hospitality of the Institute of Theoretical Physics of Hamburg University (Grant No. SFB 668) and the Institute of Theoretical Physics of ETH-Zurich is gratefully acknowledged. We would like to thank T. M. Rice, M. Sigrist, A. Läuchli, Y. Yamashita, D. van der Marel, and I. Solovyev for helpful discussions, and Y. O. Kvashnin for his assistance with Wannier function analysis. This work is supported by the grant program of President of Russian Federation under Grant No. MK-1162.2009.2, by the scientific program “Development of scientific potential of universities” under Grant No. N 2.1.1/779, by the scientific program of the Russian Federal Agency of Science and Innovation under Grant No. N 02.740.11.0217, President of Russian Federation fund for support for scientific schools under Grants No. NSH 1941.2008.2, No. RFFI 07-02-00041, and No. RFFI-09-02-00431a, grants of the Ural Division of the Russian Academy of Sciences N7 and N28. The calculations were performed on the computer cluster of “University Center of Parallel Computing” of USTU-UPI

Formation of Centauro and Strangelets in Nucleus-Nucleus Collisions at the LHC and their Identification by the ALICE Experiment

We present a phenomenological model which describes the formation of a Centauro fireball in nucleus-nucleus interactions in the upper atmosphere and at the LHC, and its decay to non-strange baryons and Strangelets. We describe the CASTOR detector for the ALICE experiment at the LHC. CASTOR will probe, in an event-by-event mode, the very forward, baryon-rich phase space 5.6 < \eta < 7.2 in 5.5 A TeV central Pb + Pb collisions. We present results of simulations for the response of the CASTOR calorimeter, and in particular to the traversal of Strangelets.Comment: 4 pages, 4 figures, to appear in the proceedings of the 26th ICR

Test of an LED Monitoring System for the PHOS Spectrometer

Preprint submitted to Elsevier Print on 26th January 2000A prototype monitoring system for the Photon Spectrometer (PHOS) of the ALICE experiment at LHC is described in detail. The prototype consists of Control and Master modules. The first one is 8x8 matrix of Light Emitting Diodes coupled with stable generators of current pulses. The system provides an individual control for each of the 64 channels of PHOS prototype based on lead-tungstate crystals. A long term stability of order of 10-3 has been achieved in integral beam tests of the monitoring system and PHOS prototypes

Степень влияния кинетической речи на восприятие представителя другой культуры (на примере политической речи)

This article focused on the question about the influence of non-verbal part of speech in perception an interlocutor as a person. In the framework of the study the experiment was done. The purpose of this experiment was studying of the impact of kinetic speech of French politics during the campaign for the presidential election in France in 2017 in perception their as persons by Russian students. The participants were asked to say about their emotions after watching two short videos, which were parts from speeches of two candidates for president. During this experiment it was detected that the speaker, who use facial expressions and gestures in not big quantities, are permitted by our mind as pleasured for communication and trustful person. Also, it was founded that overemotional kinetic speech has an opposite effect. The Lüscher eight-colour test was used to examine students in addition. It helped to found that students whose answers were opposite to answers of the main part of participants had negative emotions. It is necessary to do more complicated studies with special machines to get more detailed information about the impact of kinetic speech.Данная статья посвящена вопросу о роли невербальной составляющей речи при восприятии собеседника как личности. В рамках исследования был проведен эксперимент, целью которого было изучение степени влияния кинетической речи французских политиков во время предвыборной кампании на восприятие их как личности русскими студентами. Испытуемым было необходимо описать свои эмоции после просмотра двух коротких видеофрагментов, которые являлись отрывками из выступлений кандидатов в президенты во время выборов во Франции в 2017 году. В ходе данного эксперимента было выявлено, что ораторы, сопровождающие речь умеренной мимикой и жестикуляцией, воспринимаются нашим сознанием приятными для общения и внушающими доверие. Также было установлено, что чрезмерная жестикуляция несет обратный эффект: у аудитории происходит процесс «отторжения». В качестве инструмента дополнительной оценки испытуемых был использован восьмицветовой тест Люшера. С его помощью было выявлено, что те студенты, чьи ответы были отличны от большинства, во время проведения эксперимента испытывали негативные эмоции, причиной чего служило подавление биологических потребностей. Для более детального изучения вопроса о степени влияния невербальной коммуникации необходимы дальнейшие более сложные исследования при помощи специальной аппаратуры

The Physics of Ultraperipheral Collisions at the LHC

We discuss the physics of large impact parameter interactions at the LHC: ultraperipheral collisions (UPCs). The dominant processes in UPCs are photon-nucleon (nucleus) interactions. The current LHC detector configurations can explore small $x$ hard phenomena with nuclei and nucleons at photon-nucleon center-of-mass energies above 1 TeV, extending the $x$ range of HERA by a factor of ten. In particular, it will be possible to probe diffractive and inclusive parton densities in nuclei using several processes. The interaction of small dipoles with protons and nuclei can be investigated in elastic and quasi-elastic $J/\psi$ and $\Upsilon$ production as well as in high $t$ $\rho^0$ production accompanied by a rapidity gap. Several of these phenomena provide clean signatures of the onset of the new high gluon density QCD regime. The LHC is in the kinematic range where nonlinear effects are several times larger than at HERA. Two-photon processes in UPCs are also studied. In addition, while UPCs play a role in limiting the maximum beam luminosity, they can also be used a luminosity monitor by measuring mutual electromagnetic dissociation of the beam nuclei. We also review similar studies at HERA and RHIC as well as describe the potential use of the LHC detectors for UPC measurements.Comment: 229 Pages, 121 figure

Photon Physics in Heavy Ion Collisions at the LHC

Various pion and photon production mechanisms in high-energy nuclear collisions at RHIC and LHC are discussed. Comparison with RHIC data is done whenever possible. The prospect of using electromagnetic probes to characterize quark-gluon plasma formation is assessed.Comment: Writeup of the working group "Photon Physics" for the CERN Yellow Report on "Hard Probes in Heavy Ion Collisions at the LHC", 134 pages. One figure added in chapter 5 (comparison with PHENIX data). Some figures and correponding text corrected in chapter 6 (off-chemical equilibrium thermal photon rates). Some figures modified in chapter 7 (off-chemical equilibrium photon rates) and comparison with PHENIX data adde