4,955 research outputs found

    S-matrices of non-simply laced affine Toda theories by folding

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    The exact factorisable quantum S-matrices are known for simply laced as well as non-simply laced affine Toda field theories. Non-simply laced theories are obtained from the affine Toda theories based on simply laced algebras by folding the corresponding Dynkin diagrams. The same process, called classical `reduction', provides solutions of a non-simply laced theory from the classical solutions with special symmetries of the parent simply laced theory. In the present note we shall elevate the idea of folding and classical reduction to the quantum level. To support our views we have made some interesting observations for S-matrices of non-simply laced theories and give prescription for obtaining them through the folding of simply laced ones.Comment: 26 pages, Latex2e, 4 figure

    Sputtered gold mask for deep chemical etching of silicon

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    Sputtered mask resists chemical attack from acid and has adherence to withstand prolonged submergence in etch solution without lifting from silicon surface. Even under prolonged etch conditions with significant undercutting, gold mask maintained excellent adhesion to silicon surface and imperviousness to acid

    Organizing and Conducting an Accounting Practice

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    On the high coherence of kilo-Hz Quasi-Periodic Oscillations

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    We have carried out a systematic study of the properties of the kilo-Hertz quasi-periodic oscillations (QPO) observed in the X-ray emission of the neutron star low-mass X-ray binary 4U1608-52, using archival data obtained with the Rossi X-ray Timing Explorer. We have investigated the quality factor, Q, of the oscillations (defined as the ratio of the frequency of the QPO peak to its full width at half maximum). In order to minimise the effect of long-term frequency drifts, power spectra were computed over the shortest times permitted by the data statistics. We show that the high Q of ~200 reported by Berger et al. (1996) for the lower frequency kilo-Hz QPO in one of their observations is by no means exceptional, as we observe a mean Q value in excess of 150 in 14 out of the 21 observations analysed and Q can remain above 200 for thousands of seconds. The frequency of the QPO varies over the wide range 560--890 Hz and we find a systematic trend for the coherence time of the QPO, estimated as tau=Q /(pi nu), to increase with the frequency, up to a maximum level at ~ 800 Hz, beyond which it appears to decrease, at frequencies where the QPO weakens. There is a more complex relationship between tau and the QPO root mean squared amplitude (RMS), in which positive and negative correlations can be found. A higher-frequency QPO, revealed by correcting for the frequency drift of the 560-890 Hz one, has a much lower Q (~10) which does not follow the same pattern. We discuss these results in the framework of competing QPO models and show that those involving clumps orbiting within or above the accretion disk are ruled out.Comment: Accepted for publication in MNRAS, 8 pages, 6 figures, 3 Table

    Reporting to Clients

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    Effects of a fundamental mass term in two-dimensional super Yang-Mills theory

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    We show that adding a vacuum expectation value to a gauge field left over from a dimensional reduction of three-dimensional pure supersymmetric Yang-Mills theory generates mass terms for the fundamental fields in the two-dimensional theory while supersymmetry stays intact. This is similar to the adjoint mass term that is generated by a Chern-Simons term in this theory. We study the spectrum of the two-dimensional theory as a function of the vacuum expectation value and of the Chern-Simons coupling. Apart from some symmetry issues a straightforward picture arises. We show that at least one massless state exists if the Chern-Simons coupling vanishes. The numerical spectrum separates into (almost) massless and very heavy states as the Chern-Simons coupling grows. We present evidence that the gap survives the continuum limit. We display structure functions and other properties of some of the bound states.Comment: 17 pp., 10 figs; substantially revised version to be published in Phys. Rev.

    ‘In shape and mind transformed’? Televised teaching and learning Shakespeare

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    Reality television offers the BBC the opportunity to fulfil its dual imperatives of education and entertainment, frequently constructed as anathematic. This article considers three recent examples of televised teaching and learning Shakespeare: When Romeo Met Juliet, Macbeth, the movie star and me, and Off By Heart: Shakespeare. It demonstrates the programmes’ fit with the reality genre through their common ingredients of authenticity, contained locations, hybridity, experts, fallible and flawed participants, articulation and reconciliation of social difference. Moreover, all three share an emphasis on a reality television staple: transformation, in terms of the participants’ knowledge, skills and personal growth, but also in relation to television audiences and the British education system. The programmes might thus usefully be understood as part of a reality television subgenre, evolving in Britain since the late 1970s, of Shmake-over. This article is published as part of a collection to commemorate the 400th anniversary of William Shakespeare’s death
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