Expansion of Einstein-Yang-Mills Amplitude

In this paper, we provide a thorough study on the expansion of single trace Einstein-Yang-Mills amplitudes into linear combination of color-ordered Yang-Mills amplitudes, from various different perspectives. Using the gauge invariance principle, we propose a recursive construction, where EYM amplitude with any number of gravitons could be expanded into EYM amplitudes with less number of gravitons. Through this construction, we can write down the complete expansion of EYM amplitude in the basis of color-ordered Yang-Mills amplitudes. As a byproduct, we are able to write down the polynomial form of BCJ numerator, i.e., numerators satisfying the color-kinematic duality, for Yang-Mills amplitude. After the discussion of gauge invariance, we move to the BCFW on-shell recursion relation and discuss how the expansion can be understood from the on-shell picture. Finally, we show how to interpret the expansion from the aspect of KLT relation and the way of evaluating the expansion coefficients efficiently.Comment: 50 pages, 1 figure, Revised versio

BCS thermal vacuum of fermionic superfluids and its perturbation theory

The thermal field theory is applied to fermionic superfluids by doubling the degrees of freedom of the BCS theory. We construct the two-mode states and the corresponding Bogoliubov transformation to obtain the BCS thermal vacuum. The expectation values with respect to the BCS thermal vacuum produce the statistical average of the thermodynamic quantities. The BCS thermal vacuum allows a quantum-mechanical perturbation theory with the BCS theory serving as the unperturbed state. We evaluate the leading-order corrections to the order parameter and other physical quantities from the perturbation theory. A direct evaluation of the pairing correlation as a function of temperature shows the pseudogap phenomenon results from the perturbation theory. The BCS thermal vacuum is shown to be a generalized coherent and squeezed state. The correspondence between the thermal vacuum and purification of the density matrix allows a unitary transformation, and we found the geometric phase in the parameter space associated with the transformation.Comment: 14 pages, 2 figure

PhEDEx Data Service

The PhEDEx Data Service provides access to information from the central PhEDEx database, as well as certificate-authenticated managerial operations such as requesting the transfer or deletion of data. The Data Service is integrated with the SiteDB service for fine-grained access control, providing a safe and secure environment for operations. A plug-in architecture allows server-side modules to be developed rapidly and easily by anyone familiar with the schema, and can automatically return the data in a variety of formats for use by different client technologies. Using HTTP access via the Data Service instead of direct database connections makes it possible to build monitoring web-pages with complex drill-down operations, suitable for debugging or presentation from many aspects. This will form the basis of the new PhEDEx website in the near future, as well as providing access to PhEDEx information and certificate-authenticated services for other CMS dataflow and workflow management tools such as CRAB, WMCore, DBS and the dashboard. A PhEDEx command-line client tool provides one-stop access to all the functions of the PhEDEx Data Service interactively, for use in simple scripts that do not access the service directly. The client tool provides certificate-authenticated access to managerial functions, so all the functions of the PhEDEx Data Service are available to it. The tool can be expanded by plug-ins which can combine or extend the client-side manipulation of data from the Data Service, providing a powerful environment for manipulating data within PhEDEx

Tracking Control of Uncertain Nonholonomic Mobile Robots: Smooth Switching Approach

ABSTRACT Backstepping based adaptive tracking control of nonholonomic mobile robots in the presence of both kinematic and dynamic parametric uncertainty is presented. The major challenge is the possible singularity phenomenon due to the approach of zero of the estimated input vector field entering the denominator of the control input, a common drawback of adaptive linearization-based schemes. A hybrid control approach, which switches between an adaptive and a robust control schemes, is developed for solving such a problem. It retains the advantage of an adaptive control approach to a greatest extent while avoiding the possible blowup of the torque inputs simultaneously. A case study on a specific Type (2; 0) mobile robot is provided in the final to verify the usefulness of the proposed design

Idiopathic Superior Mesenteric Vein Thrombosis Resulting in Small Bowel Ischemia in a Pregnant Woman

Background. Small bowel ischemia due to superior mesenteric vein thrombosis (MVT) is rare during pregnancy. However, additional precipitating factors should usually be identified. Case. A 31-year-old woman, pregnant at 34 weeks, was sent to the emergency department because of acute peritonitis. An emergency exploration revealed a segmental gangrene of the small intestine without any mechanical obstruction. Together with the termination of pregnancy, resection of the damaged small bowel was performed, and an end-to-end enterostomy was followed. Based on the operative and pathological findings, small bowel ischemia might be attributed to superior mesenteric vein thrombosis. Conclusion. Hypercoagulation state normally found in pregnant women is believed to lead to this catastrophic condition without other precipitating factors