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Browsing by Author "O'Loughlin, Martin"

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Browsing by Author "O'Loughlin, Martin"

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  • 1/8 BPS States in Ads/CFT
    Gava, Edi; Milanesi, Giuseppe; Narain, Kumar S.; O'Loughlin, Martin (2006-11-09)
    We study a class of exact supersymmetric solutions of type IIB Supergravity. They have an SO(4) x SU(2) x U(1) isometry and preserve generically 4 of the 32 supersymmetries of the theory. Asymptotically AdS_5 x S^5 solutions ...
  • Aspects of plane wave (matrix) string dynamics
    Blau, Matthias; O'Loughlin, Martin; Seri, Lorenzo (Springer, 2012-04)
    We analyse two issues that arise in the context of (matrix) string theories in plane wave backgrounds, namely (1) the use of Brinkmann- versus Rosen-variables in the quantum theory for general plane waves (which we ...
  • Aspects of time-dependent backgrounds in String Theory
    Borunda, Monica (2005-07-01)
  • Boundary description of planckian scattering in curved spacetimes
    Arcioni, Giovanni; de Haro, Sebastian; O'Loughlin, Martin (IOP Publishing, 2001)
    We show that for an eikonal limit of gravity in a space-time of any dimension with a non-vanishing cosmological constant, the Einstein -- Hilbert action reduces to a boundary action. This boundary action describes the ...
  • BPS solutions in AdS/CFT
    Milanesi, Giuseppe; Gava, Edi; Narain, Kumar S.; O'Loughlin, Martin (2007-09-10)
    We study a class of exact supersymmetric solutions of type IIB Supergravity. They have an SO(4) x SU(2) x U(1) isometry and preserve generically 4 of the 32 supersymmetries of the theory. Asymptotically AdS_5 x S^5 solutions ...
  • Gödel, Penrose, anti-Mach: extra supersymmetries of time-dependent plane waves
    Blau, Matthias; Meessen, Patrick; O'Loughlin, Martin (IOP Publishing, 2003)
    We prove that M-theory plane waves with extra supersymmetries are necessarily homogeneous (but possibly time-dependent), and we show by explicit construction that such time-dependent plane waves can admit extra supersymmetries. ...
  • Half BPS states in AdS_5 x Y^{p,q}
    Gava, Edi; Narain, Kumar S.; Milanesi, Giuseppe; O'Loughlin, Martin (2007-09-19)
    We study a class of solutions of IIB Supergravity which are asymptotically AdS_5 x Y^{p,q}. They have an R x SO(4) x SU(2) x U(1) isometry and preserve half of the 8 supercharges of the background geometry. They are described ...
  • Homogeneous plane waves
    Blau, Matthias; O'Loughlin, Martin (SISSA Library, 2002)
  • Implementing holographic projections in Ponzano-Regge gravity
    Arcioni, Giovanni; Carfora, Mauro; Marzuoli, Annalisa; O'Loughlin, Martin (Elsevier, 2001)
    We consider the path-sum of Ponzano-Regge with additional boundary contributions in the context of the holographic principle of Quantum Gravity. We calculate an holographic projection in which the bulk partition function ...
  • The non-Abelian gauge theory of matrix big bangs
    O'Loughlin, Martin; Seri, Lorenzo (Springer, 2010-07-16)
    We study at the classical and quantum mechanical level the time-dependent Yang-Mills theory that one obtains via the generalisation of discrete light-cone quantisation to singular homogeneous plane waves. The non-Abelian ...
  • On the boundary dynamics of Chern-Simons gravity
    Arcioni, Giovanni; Blau, Matthias; O'Loughlin, Martin (SISSA Library, 2002)
  • On the Hagedorn behaviour of singular scale-invariant plane waves
    Blau, Matthias; Borunda, Monica; O'Loughlin, Martin (IOP Publishing, 2005-10-17)
    As a step towards understanding the properties of string theory in time-dependent and singular spacetimes, we study the divergence of density operators for string ensembles in singular scale-invariant plane waves, ...
  • Penrose limits and spacetime singularities
    Blau, Matthias; Borunda, Monica; O'Loughlin, Martin; Papadopoulos, George (IOP Publishing, 2004)
    We give a covariant characterisation of the Penrose plane wave limit: the plane wave profile matrix $A(u)$ is the restriction of the null geodesic deviation matrix (curvature tensor) of the original spacetime metric to the ...
  • Singularities and Closed Timelike Curves in type IIB 1/2 BPS Geometries
    Milanesi, Giuseppe; O'Loughlin, Martin (2006-02-20)
    We study in detail the moduli space of solutions discovered in LLM relaxing the constraint that guarantees the absence of singularities. The solutions fall into three classes, non-singular, null-singular and time machines ...
  • Solvable models of strings in homogeneous plane-wave backgrounds
    Blau, Matthias; O'Loughlin, Martin; Papadopoulos, George; Tseytlin, Arkady A. (Elsevier, 2003)
    We solve closed string theory in all regular homogeneous plane-wave backgrounds with homogeneous NS three-form field strength and a dilaton. The parameters of the model are constant symmetric and anti-symmetric matrices ...
  • Supersymmetric Solutions in AdS/CFT
    Milanesi, Giuseppe (SISSA, 2008-02-01)
    At present, microscopical physics is well described by Quantum Field Theory. In the Standard Model of particle physics, three of the four fundamental forces of nature are described by the dynamics of quantum fields. The ...
  • Two and three loop sigma-model corrections to T-duality: Kasner and Schwarzschild
    Exirifard, Ghasem; O'Loughlin, Martin (2007-11-05)
    Two and three loop alpha' corrections are calculated for Kasner and Schwarzschild metrics, and their T-duals, in the bosonic string theory. These metrics are used to obtain the two and three loop alpha' corrections to ...
  • The universality of Penrose limits near space-time singularities
    Blau, Matthias; Borunda, Monica; O'Loughlin, Martin; Papadopoulos, George (2007-11-05)
    We prove that Penrose limits of metrics with arbitrary singularities of power-law type show a universal leading u^{-2}-behaviour near the singularity provided that the dominant energy condition is satisfied and not saturated. ...