3,082 research outputs found

    Real time statistical field theory

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    We have written a {\it Mathematica} program that calculates the integrand corresponding to any amplitude in the closed-time-path formulation of real time statistical field theory. The program is designed so that it can be used by someone with no previous experience with {\it Mathematica}. It performs the contractions over the tensor indices that appear in real time statistical field theory and gives the result in the 1-2, Keldysh or RA basis. We have used the program to calculate the ward identity for the QED 3-point function, the QED 4-point function for two photons and two fermions, and the QED 5-point function for three photons and two fermions. In real time statistical field theory, there are seven 3-point functions, 15 4-point functions and 31 5-point functions. We produce a table that gives the results for all of these functions. In addition, we give a simple general expression for the KMS conditions between nn-point green functions and vertex functions, in both the Keldysh and RA basesComment: 25 pages, 12 figure

    Letter from W. T. Carrington

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    Letter concerning a department of Domestic Science at Missouri State University

    Spontaneous Symmetry Breaking for Scalar QED with Non-minimal Chern-Simons Coupling

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    We investigate the two-loop effective potential for both minimally and non-minimally coupled Maxwell-Chern-Simons theories. The non-minimal gauge interaction represents the magnetic moment interaction between a charged scalar and the electromagnetic field. In a previous paper we have shown that the two loop effective potential for this model is renormalizable with an appropriate choice of the non-minimal coupling constant. We carry out a detailed analysis of the spontaneous symmetry breaking induced by radiative corrections. As long as the renormalization point for all couplings is chosen to be the true minimum of the effective potential, both models predict the presence of spontaneous symmetry breaking. Two loop corrections are small compared to the one loop result, and thus the symmetry breaking is perturbatively stable.Comment: Revtex 25 pages, 9 figure

    Letter from W. [T. ?] Carrington to John Muir, [ca. 1898].

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    To my honored friend & fellow passenger on board the Kaiserin Auguste VictoriaMr. John MuirFrom a home where the latchstring is always out for you, where the hearthstone is ever warm for you, and where the music of your step and voice finds ever a waiting welcome.W.T. CarringtonGreenwich Conn.Tel. 284Port Chester N.Y.New York540 Park Ave.Tel. 53190987

    Infrared behaviour of the pressure in g\phi^3 theory in 6 dimensions

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    In an earlier paper Almeida and Frenkel considered the calculation of the pressure in g\phi^3 theory in 6 dimensions via the Schwinger--Dyson equation. They found, under certain approximations, that a finite result ensues in the infrared limit. We find this conclusion to remain true with certain variations of these approximations, suggesting the finiteness of the result to be fairly robust.Comment: 6 pages, 4 figures, uses revtex

    Abstract appeals to free speech won’t solve the debate surrounding Confederate monuments—it’s a political question

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    This month has seen the most recent push to remove Confederate statues in cities across the Southern US. Nathan T. Carrington and Logan Strother unpack the argument made by some who support the statues that their removal flies in the face of freedom of speech. They argue that questions over the fate of Confederate monuments are by their nature, political

    Multi-sensor Testing for Automated Rendezvous and Docking

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    During the past two years, many sensors have been tested in an open-loop fashion in the Marshall Space Flight Center (MSFC) Flight Robotics Laboratory (FRL) to both determine their suitability for use in Automated Rendezvous and Docking (AR&D) systems and to ensure the test facility is prepared for future multi-sensor testing. The primary focus of this work was in support of the CEV AR&D system, because the AR&D sensor technology area was identified as one of the top risks in the program. In 2006, four different sensors were tested individually or in a pair in the MSFC FRL. In 2007, four sensors, two each of two different types, were tested simultaneously. In each set of tests, the target was moved through a series of pre-planned trajectories while the sensor tracked it. In addition, a laser tracker "truth" sensor also measured the target motion. The tests demonstrated the functionality of testing four sensors simultaneously as well as the capabilities (both good and bad) of all of the different sensors tested. This paper outlines the test setup and conditions, briefly describes the facility, summarizes the earlier results of the individual sensor tests, and describes in some detail the results of the four-sensor testing. Post-test analysis includes data fusion by minimum variance estimation and sequential Kalman filtering. This Sensor Technology Project work was funded by NASA's Exploration Technology Development Program

    Energy Flow in Acoustic Black Holes

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    We present the results of an analysis of superradiant energy flow due to scalar fields incident on an acoustic black hole. In addition to providing independent confirmation of the recent results in [5], we determine in detail the profile of energy flow everywhere outside the horizon. We confirm explicitly that in a suitable frame the energy flow is inward at the horizon and outward at infinity, as expected on physical grounds.Comment: 8 pages, 9 figures, Comments added to discussion of energy flow and introductory section abbreviate
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