1,204 research outputs found

    On the naturality of the Mathai-Quillen formula

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    We give an alternative proof for the Mathai-Quillen formula for a Thom form using its natural behaviour with respect to fiberwise integration. We also study this phenomenon in general context.Comment: 6 page

    Electrical and Thermal Properties of PbTe Doped with Magnetic Impurities

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    Can coarse-graining introduce long-range correlations in a symbolic sequence?

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    We present an exactly solvable mean-field-like theory of correlated ternary sequences which are actually systems with two independent parameters. Depending on the values of these parameters, the variance on the average number of any given symbol shows a linear or a superlinear dependence on the length of the sequence. We have shown that the available phase space of the system is made up a diffusive region surrounded by a superdiffusive region. Motivated by the fact that the diffusive portion of the phase space is larger than that for the binary, we have studied the mapping between these two. We have identified the region of the ternary phase space, particularly the diffusive part, that gets mapped into the superdiffusive regime of the binary. This exact mapping implies that long-range correlation found in a lower dimensional representative sequence may not, in general, correspond to the correlation properties of the original system.Comment: 10 pages including 1 figur

    Lattice Gauge Fields Topology Uncovered by Quaternionic sigma-model Embedding

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    We investigate SU(2) gauge fields topology using new approach, which exploits the well known connection between SU(2) gauge theory and quaternionic projective sigma-models and allows to formulate the topological charge density entirely in terms of sigma-model fields. The method is studied in details and for thermalized vacuum configurations is shown to be compatible with overlap-based definition. We confirm that the topological charge is distributed in localized four dimensional regions which, however, are not compatible with instantons. Topological density bulk distribution is investigated at different lattice spacings and is shown to possess some universal properties.Comment: revtex4, 19 pages (24 ps figures included); replaced to match the published version, to appear in PRD; minor changes, references adde

    Recovery of Ammonium Nitrate and Reusable Acetic Acid from Effluent Generated during HMX Production

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    Production of HMX on commercial scale is mainly carried out by modified Bachmann process, and acetic acid constitutes major portion of effluenttspent liquor produced during this process. The recovery of glacial acetic acid from this spent liquor is essential to make the process commercially viable besides making it eco-friendly by minimising the quantity of disposable effluent. The recovery of glacial acetic acid from spent liquor is not advisable by simple distillation since it contains, in addition to acetic acid, a small fraction of nitric acid, traces of RDX, HMX, and undesired nitro compounds. The process normally involves neutralising the spent mother liquor with liquor ammonia and then distillating the ueutralised mother liquor under vacuum to recover dilute acetic acid (strength approx. 30 %). The dilute acetic acid, in turn, is concentrated to glacial acetic acid by counter current solvent extraction, followed by distillation. The process is very lengthy and the energy requirement is also veryhigh, rendering the process economically unviable. Hence, a novel method has been developed on bench-scale to obtain glacial acetic acid directly from the mother liquor after the second ageing process

    Brauer group of moduli spaces of pairs

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    We show that the Brauer group of any moduli space of stable pairs with fixed determinant over a curve is zero.Comment: 12 pages. Final version, accepted in Communications in Algebr

    Billiard algebra, integrable line congruences, and double reflection nets

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    The billiard systems within quadrics, playing the role of discrete analogues of geodesics on ellipsoids, are incorporated into the theory of integrable quad-graphs. An initial observation is that the Six-pointed star theorem, as the operational consistency for the billiard algebra, is equivalent to an integrabilty condition of a line congruence. A new notion of the double-reflection nets as a subclass of dual Darboux nets associated with pencils of quadrics is introduced, basic properies and several examples are presented. Corresponding Yang-Baxter maps, associated with pencils of quadrics are defined and discussed.Comment: 18 pages, 8 figure

    Geometric Phase in Eigenspace Evolution of Invariant and Adiabatic Action Operators

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    The theory of geometric phase is generalized to a cyclic evolution of the eigenspace of an invariant operator with NN-fold degeneracy. The corresponding geometric phase is interpreted as a holonomy inherited from the universal connection of a Stiefel U(N)-bundle over a Grassmann manifold. Most significantly, for an arbitrary initial state, this geometric phase captures the inherent geometric feature of the state evolution. Moreover, the geometric phase in the evolution of the eigenspace of an adiabatic action operator is also addressed, which is elaborated by a pullback U(N)-bundle. Several intriguing physical examples are illustrated.Comment: Added Refs. and corrected typos; 4 page

    The Best Laid Plans: Access to the Rajiv Aarogyasri community health insurance scheme of Andhra Pradesh

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    This paper is a qualitative assessment of a public health insurance scheme in the state of Andhra Pradesh, south India, called the Rajiv Aarogyasri Community Health Insurance Scheme (or Aarogyasri), using the case-study method. Focusing on inpatient hospital care and especially on surgical treatments leaves the scheme wanting in meeting the health care needs of and addressing the impoverishing health expenditure incurred by the poor, especially those living in rural areas. Though well-intentioned, people from vulnerable sections of society may find the scheme ultimately unhelpful for their needs. Through an in-depth qualitative approach, the paper highlights not just financial difficulties but also the non-financial barriers to accessing health care, despite the existence of a scheme such as Aarogyasri. Narrative evidence from poor households offers powerful insights into why even the most innovative state health insurance schemes may not achieve their goals and systemic corrections needed to address barriers to health care
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