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1,243
Existence of generalized Kodama states. IV. The search for a quantization of 4dimensional gravity
, 2008
"... This is the fourth in a series of papers outlining an algorithm to consistently construct a finite quantum theory of gravity in Ashtekar variables. This paper continues essentially from where papers II and III left off, treating the kinematic constraints in greater depth and moving on to a higher le ..."
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level of complexity with regard to the Hamiltonian constraint of the full, unrestricted, theory. First we identify some of the traditional obstacles to the consistent quantization of fourdimensional gravity, then provide suggestions for how these obstacles may possibly be surmounted within the context
The hierarchy problem and new dimensions at a millimeter
, 2008
"... We propose a new framework for solving the hierarchy problem which does not rely on either supersymmetry or technicolor. In this framework, the gravitational and gauge interactions become united at the weak scale, which we take as the only fundamental short distance scale in nature. The observed wea ..."
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Cited by 664 (5 self)
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propagate in the new dimensions, at subweak energies the Standard Model (SM) fields must be localized to a 4dimensional manifold of weak
Spin Foam Models for Quantum Gravity
, 2008
"... In this article we review the present status of the spin foam formulation of nonperturbative (background independent) quantum gravity. The article is divided in two parts. In the first part we present a general introduction to the main ideas emphasizing their motivations from various perspectives. R ..."
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Cited by 123 (7 self)
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. Riemannian 3dimensional gravity is used as a simple example to illustrate conceptual issues and the main goals of the approach. The main features of the various existing models for 4dimensional gravity are also presented here. We conclude with a discussion of important questions to be addressed in four
Relativistic Spin Networks and Quantum Gravity
 J. Math Phys
, 1998
"... Abstract. Relativistic spin networks are defined by considering the spin covering of the group SO(4), SU(2) × SU(2). Relativistic quantum spins are related to the geometry of the 2dimensional faces of a 4simplex. This extends the idea of Ponzano and Regge that SU(2) spins are related to the geome ..."
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Cited by 180 (17 self)
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to the geometry of the edges of a 3simplex. This leads us to suggest that there may be a 4dimensional state sum model for quantum gravity based on relativistic spin networks which parallels the construction of 3dimensional quantum gravity from ordinary spin networks.
Renormalization group flows from holography  Supersymmetry and a ctheorem
 ADV THEOR. MATH. PHYS
, 1999
"... We obtain first order equations that determine a supersymmetric kink solution in fivedimensional N = 8 gauged supergravity. The kink interpolates between an exterior antide Sitter region with maximal supersymmetry and an interior antide Sitter region with one quarter of the maximal supersymmetry. ..."
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Cited by 294 (25 self)
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sector of N = 2 gauge theories based on quiver diagrams. We consider more general kink geometries and construct a cfunction that is positive and monotonic if a weak energy condition holds in the bulk gravity theory. For evendimensional boundaries, the cfunction coincides with the trace anomaly
GRAVITY
, 1998
"... We discuss the relation between canonical and Schrödinger quantization of the CGHS model. We also discuss the situation when background charges are added to cancel the Virasoro anomaly. New physical states are found when the square of the background charges vanishes. 1 The quantization of reparametr ..."
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of reparametrization invariant theories. In particular the string inspired CGHS (Callan, Giddings, Harvey and Strominger) model [1] was intensively investigated. The CHGS model consists of a particular coupling of two–dimensional gravity and a dilaton field. It is described by the action S = d 2 x √ −g e −2φ (R + 4g
gravity
, 1998
"... We derive a first order formalism for solving the scattering of point sources in (2+1) gravity with negative cosmological constant. We show that their physical motion can be mapped, with a polydromic coordinate transformation, to a trivial motion, in such a way that the point sources move as timeli ..."
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we would like to study the problem of treating the interaction between particles and AdS gravity, generalizing our previous investigation in (2+1) gravity and its supergravity extension, which has also been considered by many other authors [1][2][3][4][5][6][7][8][9][10]. The problem from a
gravity
, 1995
"... We use gravitational lagrangians R✷kR √ −g and linear combinations of them; we ask under which circumstances the de Sitter spacetime represents an attractor solution in the set of spatially flat Friedman models. Results are: For arbitrary k, i.e., for arbitrarily large order 2k + 4 of the field equa ..."
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equation, on can always find examples where the attractor property takes place. Such examples necessarily need a nonvanishing R2term. The main formulas do not depend on the dimension, so one 1 gets similar results also for 1+1dimensional gravity and for KaluzaKlein cosmology. PACS number: 0450 Unified
4dimensional BF Gravity on the Lattice
, 1999
"... We propose the lattice version of BF gravity action whose partition function leads to the product of a particular form of 15j symbol which corresponds to a 4simplex. The action is explicitly constructed by lattice B field defined on triangles and link variables defined on dual links and is shown t ..."
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Cited by 1 (0 self)
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We propose the lattice version of BF gravity action whose partition function leads to the product of a particular form of 15j symbol which corresponds to a 4simplex. The action is explicitly constructed by lattice B field defined on triangles and link variables defined on dual links and is shown
Spin Gauge Theory of Gravity in Clifford Space 1
, 2005
"... A theory in which 16dimensional curved Clifford space (Cspace) provides a realization of KaluzaKlein theory is investigated. No extra dimensions of spacetime are needed: “extra dimensions ” are in Cspace. We explore the spin gauge theory in Cspace and show that the generalized spin connection c ..."
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contains the usual 4dimensional gravity and YangMills fields of the U(1)×SU(2)×SU(3) gauge group. The representation space for the latter group is provided by 16component generalized spinors composed of four usual 4component spinors, defined geometrically as the members of four independent minimal left
Results 1  10
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1,243