Coherent Waveform Consistency Test for LIGO Burst Candidates

The burst search in LIGO relies on the coincident detection of transient signals in multiple interferometers. As only minimal assumptions are made about the event waveform or duration, the analysis pipeline requires loose coincidence in time, frequency and amplitude. Confidence in the resulting events and their waveform consistency is established through a time-domain coherent analysis: the r-statistic test. This paper presents a performance study of the r-statistic test for triple coincidence events in the second LIGO Science Run (S2), with emphasis on its ability to suppress the background false rate and its efficiency at detecting simulated bursts of different waveforms close to the S2 sensitivity curve.Comment: 11 pages, 9 figures. Submitted to the Proceedings of the 8th Gravitational Wave Data Analysis Workshop, in Classic and Quantum Gravit

Performance of the WaveBurst algorithm on LIGO data

In this paper we describe the performance of the WaveBurst algorithm which was designed for detection of gravitational wave bursts in interferometric data. The performance of the algorithm was evaluated on the test data set collected during the second LIGO Scientific run. We have measured the false alarm rate of the algorithm as a function of the threshold and estimated its detection efficiency for simulated burst waveforms.Comment: proceedings of GWDAW, 2003 conference, 13 pages, 6 figure

Dynamics of noisy oscillator populations beyond the Ott-Antonsen ansatz

We develop an approach for the description of the dynamics of large populations of phase oscillators based on "circular cumulants" instead of the Kuramoto-Daido order parameters. In the thermodynamic limit, these variables yield a simple representation of the Ott-Antonsen invariant solution [E. Ott and T. M. Antonsen, CHAOS 18, 037113 (2008)] and appear appropriate for constructing the perturbation theory on top of the Ott-Antonsen ansatz. We employ this approach to study the impact of small intrinsic noise on the dynamics. As a result, a closed system of equations for the two leading cumulants, describing the dynamics of noisy ensembles, is derived. We exemplify the general theory by presenting the effect of noise on the Kuramoto system and on a chimera state in two symmetrically coupled populations.Comment: 5 pages, 2 figure

Competition of Color Ferromagnetic and Superconductive States in a Quark-Gluon System

The possibility of color ferromagnetism in an SU(2) gauge field model is investigated. The conditions allowing a stable color ferromagnetic state of the quark system in the chromomagnetic field occupying small domains are considered. A phase transition between this state and the color superconducting state is considered. The effect of finite temperature is analyzed.Comment: 21 pages, 4 Postscript figure

Constructive summation of the (2,2) quasi normal mode from a population of black holes

The quasi normal modes (QNMs) associated with gravitational-wave signals from binary black hole (BBH) mergers can provide deep insight into the remnant's properties. Once design sensitivity is achieved, present ground-based gravitational wave interferometers could detect potentially hundreds of BBH signals in the coming years. For most, the ringdown phase will have a very weak signal-to-noise ratio (SNR). Signal summation techniques allow information extraction from the weak SNR ringdowns. We propose a method to constructively sum the (2,2) QNM from different BBH signals by synchronizing and rescaling them. The parameter space adopted to test the method is presently limited to mass ratio $q\leq3$, initially non-spinning black holes with face-on orientation. Moreover, since the synchronisation procedure fails for the weakest signals, we select all ringdowns with SNR above 2.6. Under these conditions, we show that for different BBH populations, 40 to 70% of all the potential detections could be used for the summation while still ensuring a summed SNR of $\sim$80% of the maximal achievable SNR (i.e. for ideally synchronized signals).Comment: 7 pages, 10 figure

New phase structure of the Nambu -- Jona - Lasinio model at nonzero chemical potential

It is shown that in the Nambu -- Jona - Lasinio model at nonzero chemical potential there are two different massive phases with spontaneously broken chiral symmetry. In one of them particle density is identically zero, in another phase it is not equal to zero. The transition between phases is a phase transition of the second order.Comment: 8 pages, LaTeX, no figures

Трансграничное взаимодействие в системе высшего профессионального образования: цели и перспективы

The necessity of cross-border cooperation between higher education institutions of the Member States of the customs union. Addresses the general concerns and identifying possible methods of solving problems. It is proposed to establish a center of innovative technologies that will provide effective transboundary collaboration of higher education institutions of the Member States of the customs union.В статье обосновывается необходимость трансграничного сотрудничества высших учебных заведений стран-участников таможенного союза. Рассматриваются общие проблемные вопросы и определяются возможные методы решения проблем. Предлагается создать центр инновационных технологий, который обеспечит эффективное трансграничное взаимодействие высших учебных заведений стран- участников таможенного союза

On the need for informal approach to formal education or some of the arguments in defense of the traditional education system

The author questions the appropriateness of the mass distribution of elearning. Arguments in favor of the classical formal education in the training of engineers and technical specialists. It is proposed to position e-learning as a tool solution of particular problems of education.Автор подвергает сомнению целесообразность массового распространения электронного обучения. Приводятся аргументы в пользу классического формального образования при подготовке инженеров и специалистов технического профиля. Предлагается позиционировать электронное обучение, как инструментальное средство решения частных задач образования

Collective mode reductions for populations of coupled noisy oscillators

We analyze accuracy of different low-dimensional reductions of the collective dynamics in large populations of coupled phase oscillators with intrinsic noise. Three approximations are considered: (i) the Ott-Antonsen ansatz, (ii) the Gaussian ansatz, and (iii) a two-cumulant truncation of the circular cumulant representation of the original system's dynamics. For the latter we suggest a closure, which makes the truncation, for small noise, a rigorous first-order correction to the Ott-Antonsen ansatz, and simultaneously is a generalization of the Gaussian ansatz. The Kuramoto model with intrinsic noise, and the population of identical noisy active rotators in excitable states with the Kuramoto-type coupling, are considered as examples to test validity of these approximations. For all considered cases, the Gaussian ansatz is found to be more accurate than the Ott-Antonsen one for high-synchrony states only. The two-cumulant approximation is always superior to both other approximations.Comment: 7 pages, 4 figures [compared to the journal version, typo in Eq.(22) corrected