13,501 research outputs found

    New Gauged N=8, D=4 Supergravities

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    New gaugings of four dimensional N=8 supergravity are constructed, including one which has a Minkowski space vacuum that preserves N=2 supersymmetry and in which the gauge group is broken to SU(3)xU(1)2SU(3)xU(1)^2. Previous gaugings used the form of the ungauged action which is invariant under a rigid SL(8,R)SL(8,R) symmetry and promoted a 28-dimensional subgroup (SO(8),SO(p,8p)SO(8),SO(p,8-p) or the non-semi-simple contraction CSO(p,q,8pq)CSO(p,q,8-p-q)) to a local gauge group. Here, a dual form of the ungauged action is used which is invariant under SU(8)SU^*(8) instead of SL(8,R)SL(8,R) and new theories are obtained by gauging 28-dimensional subgroups of SU(8)SU^*(8). The gauge groups are non-semi-simple and are different real forms of the CSO(2p,82p)CSO(2p,8-2p) groups, denoted CSO(2p,82p)CSO^*(2p,8-2p), and the new theories have a rigid SU(2) symmetry. The five dimensional gauged N=8 supergravities are dimensionally reduced to D=4. The D=5,SO(p,6p)D=5,SO(p,6-p) gauge theories reduce, after a duality transformation, to the D=4,CSO(p,6p,2)D=4,CSO(p,6-p,2) gauging while the SO(6)SO^*(6) gauge theory reduces to the D=4,CSO(6,2)D=4, CSO^*(6,2) gauge theory. The new theories are related to the old ones via an analytic continuation. The non-semi-simple gaugings can be dualised to forms with different gauge groups.Comment: 33 pages. Reference adde

    De Sitter Space in Supergravity and M Theory

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    Two ways in which de Sitter space can arise in supergravity theories are discussed. In the first, it arises as a solution of a conventional supergravity, in which case it necessarily has no Killing spinors. For example, de Sitter space can arise as a solution of N=8 gauged supergravities in four or five dimensions. These lift to solutions of 11-dimensional supergravity or D=10 IIB supergravity which are warped products of de Sitter space and non-compact spaces of negative curvature. In the second way, de Sitter space can arise as a supersymmetric solution of an unconventional supergravity theory, which typically has some kinetic terms with the `wrong' sign; such solutions are invariant under a de Sitter supergroup. Such solutions lift to supersymmetric solutions of unconventional supergravities in D=10 or D=11, which nonetheless arise as field theory limits of theories that can be obtained from M-theory by timelike T-dualities and related dualities. Brane solutions interpolate between these solutions and flat space and lead to a holographic duality between theories in de Sitter vacua and Euclidean conformal field theories. Previous results are reviewed and generalised, and discussion is included of Kaluza-Klein theory with non-compact internal spaces, brane and cosmological solutions, and holography on de Sitter spaces and product spaces.Comment: Referneces added, 36 page

    Gauged Heterotic Sigma-Models

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    The gauging of isometries in general sigma-models which include fermionic terms which represent the interaction of strings with background Yang-Mills fields is considered. Gauging is possible only if certain obstructions are absent. The quantum gauge anomaly is discussed, and the (1,0) supersymmetric generalisation of the gauged action given.Comment: 10 pages, phyzzx, QMW-93-25 (Blank lines created by mailer removed, so this version should be TeXable

    U-Duality and BPS Spectrum of Super Yang-Mills Theory and M-Theory

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    It is shown that the BPS spectrum of Super-Yang-Mills theory on Td×RT^d\times \R, which fits into representations of the U-duality group for M-theory compactified on TdT^{d}, in accordance with the matrix-theory conjecture, in fact fits into representations of the U-duality group for M-theory on Td+1T^{d+1}, the extra dualities realised as generalised Nahm transformations. The spectrum of BPS M-branes is analysed, new branes are discussed and matrix theory applications described.Comment: 18 Pages, Tex, Phyzzx Macro. References added, minor correction

    Matrix Theory, U-Duality and Toroidal Compactifications of M-Theory

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    Using U-duality, the properties of the matrix theories corresponding to the compactification of M-theory on TdT^d are investigated. The couplings of the d+1d+1 dimensional effective Super-Yang-Mills theory to all the M-theory moduli is deduced and the spectrum of BPS branes in the SYM gives the corresponding spectrum of the matrix theory.Known results are recovered for d5d\le 5 and predictions for d>5d>5 are proposed. For d>3d>3, the spectrum includes d4d-4 branes arising from YM instantons, and U-duality interchanges momentum modes with brane wrapping modes.For d=6d=6, there is a generalised th\th -angle which couples to instantonic 3-branes and which combines with the SYM coupling constant to take values in SL(2,R)/U(1)SL(2,\R)/U(1), acted on by an SL(2,Z)SL(2,\Z) subgroup of the U-duality group E6(Z)E_6(\Z). For d=4,7,8d=4,7,8, there is an SL(d+1)SL(d+1) symmetry, suggesting that the matrix theory could be a scale-invariant d+2d+2 dimensional theory on Td+1×RT^{d+1} \times \R in these cases, as is already known to be the case for d=4d=4; evidence is found suggesting this happens for d=8d=8 but not d=7d=7.Comment: 28 Pages, Phyzzx Macro. Minor correction
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