359 research outputs found

    M-theory, the signature theorem, and geometric invariants

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    The equations of motion and the Bianchi identity of the C-field in M-theory are encoded in terms of the signature operator. We then reformulate the topological part of the action in M-theory using the signature, which leads to connections to the geometry of the underlying manifold, including positive scalar curvature. This results in a variation on the miraculous cancellation formula of Alvarez-Gaum\'e and Witten in twelve dimensions and leads naturally to the Kreck-Stolz s-invariant in eleven dimensions. Hence M-theory detects diffeomorphism type of eleven-dimensional (and seven-dimensional) manifolds, and in the restriction to parallelizable manifolds classifies topological eleven-spheres. Furthermore, requiring the phase of the partition function to be anomaly-free imposes restrictions on allowed values of the s-invariant. Relating to string theory in ten dimensions amounts to viewing the bounding theory as a disk bundle, for which we study the corresponding phase in this formulation.Comment: 17 page

    Quantum discontinuity between zero and infinitesimal graviton mass with a Lambda term

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    We show that the recently demonstrated absence of the usual discontinuity for massive spin 2 with a Lambda term is an artifact of the tree approximation, and that the discontinuity reappears at one loop.Comment: 8 pages, revtex 3.1, title changed (version to appear in Phys. Rev. Lett.

    The Elliptic curves in gauge theory, string theory, and cohomology

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    Elliptic curves play a natural and important role in elliptic cohomology. In earlier work with I. Kriz, thes elliptic curves were interpreted physically in two ways: as corresponding to the intersection of M2 and M5 in the context of (the reduction of M-theory to) type IIA and as the elliptic fiber leading to F-theory for type IIB. In this paper we elaborate on the physical setting for various generalized cohomology theories, including elliptic cohomology, and we note that the above two seemingly unrelated descriptions can be unified using Sen's picture of the orientifold limit of F-theory compactification on K3, which unifies the Seiberg-Witten curve with the F-theory curve, and through which we naturally explain the constancy of the modulus that emerges from elliptic cohomology. This also clarifies the orbifolding performed in the previous work and justifies the appearance of the w_4 condition in the elliptic refinement of the mod 2 part of the partition function. We comment on the cohomology theory needed for the case when the modular parameter varies in the base of the elliptic fibration.Comment: 23 pages, typos corrected, minor clarification

    Duality symmetry and the form fields of M-theory

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    In previous work we derived the topological terms in the M-theory action in terms of certain characters that we defined. In this paper, we propose the extention of these characters to include the dual fields. The unified treatment of the M-theory four-form field strength and its dual leads to several observations. In particular we elaborate on the possibility of a twisted cohomology theory with a twist given by degrees greater than three.Comment: 12 pages, modified material on the differentia

    Quantum M^2 -> 2Lambda/3 discontinuity for massive gravity with a Lambda term

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    In a previous paper we showed that the absence of the van Dam-Veltman-Zakharov discontinuity as M^2 -> 0 for massive spin-2 with a Lambda term is an artifact of the tree approximation, and that the discontinuity reappears at one loop, as a result of going from five degrees of freedom to two. In this paper we show that a similar classical continuity but quantum discontinuity arises in the "partially massless" limit M^2 -> 2Lambda/3, as a result of going from five degrees of freedom to four.Comment: 8 pages, REVTe

    Principal infinity-bundles - General theory

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    The theory of principal bundles makes sense in any infinity-topos, such as that of topological, of smooth, or of otherwise geometric infinity-groupoids/infinity-stacks, and more generally in slices of these. It provides a natural geometric model for structured higher nonabelian cohomology and controls general fiber bundles in terms of associated bundles. For suitable choices of structure infinity-group G these G-principal infinity-bundles reproduce the theories of ordinary principal bundles, of bundle gerbes/principal 2-bundles and of bundle 2-gerbes and generalize these to their further higher and equivariant analogs. The induced associated infinity-bundles subsume the notions of gerbes and higher gerbes in the literature. We discuss here this general theory of principal infinity-bundles, intimately related to the axioms of Giraud, Toen-Vezzosi, Rezk and Lurie that characterize infinity-toposes. We show a natural equivalence between principal infinity-bundles and intrinsic nonabelian cocycles, implying the classification of principal infinity-bundles by nonabelian sheaf hyper-cohomology. We observe that the theory of geometric fiber infinity-bundles associated to principal infinity-bundles subsumes a theory of infinity-gerbes and of twisted infinity-bundles, with twists deriving from local coefficient infinity-bundles, which we define, relate to extensions of principal infinity-bundles and show to be classified by a corresponding notion of twisted cohomology, identified with the cohomology of a corresponding slice infinity-topos. In a companion article [NSSb] we discuss explicit presentations of this theory in categories of simplicial (pre)sheaves by hyper-Cech cohomology and by simplicial weakly-principal bundles; and in [NSSc] we discuss various examples and applications of the theory.Comment: 46 pages, published versio

    Integral group actions on symmetric spaces and discrete duality symmetries of supergravity theories

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    For G(R)G(\mathbb{R}) a split, simply connected, semisimple Lie group of rank nn and KK the maximal compact subgroup of GG, we give a method for computing Iwasawa coordinates of G/KG/K using the Chevalley generators and the Steinberg presentation. When G/KG/K is a scalar coset for a supergravity theory in dimensions 3\geq 3, we determine the action of the integral form G(Z)G(\mathbb{Z}) on G/KG/K. We give explicit results for the action of the discrete UU--duality groups SL2(Z)SL_2(\mathbb{Z}) and E7(Z)E_7(\mathbb{Z}) on the scalar cosets SL2(R)/SO2(R)SL_2(\mathbb{R})/SO_2(\mathbb{R}) and E7(+7)(R)/[SU(8,R)/{±Id}]E_{7(+7)}(\mathbb{R})/[SU(8,\mathbb{R})/\{\pm Id\}] for type IIB supergravity in ten dimensions and 11--dimensional supergravity in D=4D=4 dimensions, respectively. For the former, we use this to determine the discrete U--duality transformations on the scalar sector in the Borel gauge and we describe the discrete symmetries of the dyonic charge lattice. We determine the spectrum--generating symmetry group for fundamental BPS solitons of type IIB supergravity in D=10D=10 dimensions at the classical level and we propose an analog of this symmetry at the quantum level. We indicate how our methods can be used to study the orbits of discrete U--duality groups in general

    Effects of Moringa (Moringa oleifera Lam.) Leaf Meal on Performance, Carcass, Organs, Eggs and Meat of Japanese Quails

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    There are several reports on the utilisation of Moringa oleifera in poultry diets due to its essential bioactive compounds yet,little is known about its influence on Japanese quail eggs and meat qualities. Hence, the need to examine performance, eggs and meat qualities of Japanese quail hens fed M.oleifera leaf. To achieve this, 240 Japanese quail chicks were allocated to three dietary treatments: D1: control, 0.0% (without M. oleifera leaf meal),D2: (0.5% M. oleifera leaf meal) and D3: (1% M.oleifera leaf meal). Data on performance, carcass, organs, eggs and meat qualities were collected and subjected to ANOVA at 0.05. Results revealed that feed consumption was lowest (2,701g) in D1 and highest (2,800g) in D2, carcass weight varied from 100 - 100.67g, thigh weight (12.66 - 13.58g) and breast weight was highest (40.41g) in D3. Liver weight was lowest (3.25g) in D1, kidney was largest (0.91g) in D3 whereas, the heart, gizzard and spleen weights ranged from 1.00 - 1.16g, 3.08 - 3.50g and 0.04 - 0.08g, respectively. In the eggs, crude protein (10.94%), crude fat (6.71%), ash (1.36%), high-density lipoprotein (96.12mg/100g) and low-density lipoprotein (120.67mg/100g) were highest in D1. Total cholesterol (364.08mg/100g) and triglycerides (147.27mg/100g) were least in D1 and the caloric value varied from 1.46 -1.47kcal/g. In the meat, crude protein (17.14%) and energy value (1.96kcal/g) were best in D2 but, crude fat (12.62%), ash (2.85%) and carbohydrates(1.31%) were superior in D3. In both eggs and meat, no crude fibre (0.0%) was detected. In any case, all the parameter values were within the normal ranges given in healthy Japanese quails at similar age. Consequently,addition of M. oleifera leaf meal at 1.0% to Japanese quail diets might not depress performance, affect carcass quality, cause organs dysfunctions but may improve nutritional quality of the eggs and meat
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