Testing a Fourier Accelerated Hybrid Monte Carlo Algorithm

We describe a Fourier Accelerated Hybrid Monte Carlo algorithm suitable for dynamical fermion simulations of non-gauge models. We test the algorithm in supersymmetric quantum mechanics viewed as a one-dimensional Euclidean lattice field theory. We find dramatic reductions in the autocorrelation time of the algorithm in comparison to standard HMC.Comment: 9 pages, 3 figure

Testing a Fourier Accelerated Hybrid Monte Carlo Algorithm

We describe a Fourier Accelerated Hybrid Monte Carlo algorithm suitable for dynamical fermion simulations of non-gauge models. We test the algorithm in supersymmetric quantum mechanics viewed as a one-dimensional Euclidean lattice field theory. We find dramatic reductions in the autocorrelation time of the algorithm in comparison to standard HMC

A Two-Dimensional Lattice Model with Exact Supersymmetry

Starting from a simple discrete model which exhibits a supersymmetric invariance we construct a local, interacting, two-dimensional Euclidean lattice theory which also admits an exact supersymmetry. This model is shown to correspond to the Wess-Zumino model with extended N=2 supersymmetry in the continuum. We have performed dynamical fermion simulations to check the spectrum and supersymmetric Ward identities and find good agreement with theory

Exact Lattice Supersymmetry: the Two-Dimensional N=2 Wess-Zumino Model

We study the two-dimensional Wess-Zumino model with extended N=2 supersymmetry on the lattice. The lattice prescription we choose has the merit of preserving {\it exactly} a single supersymmetric invariance at finite lattice spacing $a$. Furthermore, we construct three other transformations of the lattice fields under which the variation of the lattice action vanishes to $O(ga^2)$ where $g$ is a typical interaction coupling. These four transformations correspond to the two Majorana supercharges of the continuum theory. We also derive lattice Ward identities corresponding to these exact and approximate symmetries. We use dynamical fermion simulations to check the equality of the massgaps in the boson and fermion sectors and to check the lattice Ward identities. At least for weak coupling we see no problems associated with a lack of reflection positivity in the lattice action and find good agreement with theory. At strong coupling we provide evidence that problems associated with a lack of reflection positivity are evaded for small enough lattice spacing.Comment: 29 pages, 10 figures. New results at strong coupling added. Minor corrections to text and one reference added. Version to appear in Phys. Rev.

A lattice study of the two-dimensional Wess Zumino model

We present results from a numerical simulation of the two-dimensional Euclidean Wess-Zumino model. In the continuum the theory possesses N=1 supersymmetry. The lattice model we employ was analyzed by Golterman and Petcher in \cite{susy} where a perturbative proof was given that the continuum supersymmetric Ward identities are recovered without finite tuning in the limit of vanishing lattice spacing. Our simulations demonstrate the existence of important non-perturbative effects in finite volumes which modify these conclusions. It appears that in certain regions of parameter space the vacuum state can contain solitons corresponding to field configurations which interpolate between different classical vacua. In the background of these solitons supersymmetry is partially broken and a light fermion mode is observed. At fixed coupling the critical mass separating phases of broken and unbroken supersymmetry appears to be volume dependent. We discuss the implications of our results for continuum supersymmetry breaking.Comment: 32 pages, 12 figure

Media as an Administrative Resource in the Electoral Process (following the Example of the Sverdlovsk Region)

Статья поступила в редакцию 23.11.2022 г.Рассматривается участие средств массовой информации (СМИ) в избирательном процессе. Анализируется известная политико-правовая проблема, когда правоприменение ведется на уровне отдельных кейсов, а научное обобщение нарушений закона поднимается до уровня абстракции. На примере Свердловской области медиа рассматриваются не только как политический актор избирательного процесса. На основе Избирательного кодекса Свердловской области показаны формально-юридические основания статуса СМИ. Используется метод компаративистики — сравниваются электоральные технологии кандидатов на должность губернатора Свердловской области. Как результат компаративистского исследования показаны официальная, оппозиционная и нейтрально-отстраненная позиции СМИ по отношению к кандидатам. Впервые выведена типология электоральных СМИ.The participation of mass media in the electoral process is considered. A well known political and legal problem is resolved: law enforcement is conducted at the level of individual cases, and the scientific generalization of violations of the law soars to the level of abstraction. Using the example of the Sverdlovsk region, the media are considered not only as a political actor in the electoral process. On the basis of the Electoral Code of the Sverdlovsk region (ECSR), the formal and legal grounds for the status of the media are shown. The method of comparative studies is used — electoral technologies of candidates for the post of Governor of the Sverdlovsk region are compared. As a result of the comparative study, the official, oppositional and neutral estranged positions of the media in relation to the candidates are shown. For the first time, the typology of electoral media is derived

Observation of New States Decaying into Λc+π−π+\Lambda_{c}^{+}\pi^{-}\pi^{+}

Using 13.7 fb^{-1} of data recorded by the CLEO detector at CESR, we investigate the spectrum of charmed baryons which decay into Lambda_c^+ pi^- pi^+ and are more massive than the Lambda_{c1} baryons. We find evidence for two new states: one is broad and has an invariant mass roughly 480 MeV above that of the Lambda_c^+; the other is narrow with an invariant mass of 596 +- 1 +- 2 MeV above the Lambda_c^+ mass. These results are preliminary.Comment: 11 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

Search for a Scalar Bottom Quark with Mass 3.5-4.5 GeV/c2c^{2}

We report on a search for a supersymmetric $\tilde{B}$ meson with mass between 3.5 and 4.5 GeV/$c^2$ using 4.52 ${\rm fb}^{-1}$ of integrated luminosity produced at $\sqrt{s}=10.52$ GeV, just below the $e^+e^-\to B\bar{B}$ threshold, and collected with the CLEO detector. We find no evidence for a light scalar bottom quark.Comment: 10 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN