Publications (223)717.35 Total impact
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ABSTRACT: Hypergravity is the theory in which the graviton, of spin2, has a supersymmetric partner of spin5/2. There are "nogo" theorems that prevent interactions in these higher spin theories. However, it appears that one can circumvent them by bringing in an infinite tower of higher spin fields. With this possibility in mind, we study herein the electricmagnetic duality invariance of hypergravity. The analysis is carried out in detail for the free theory of the spin(2,5/2) multiplet, and it is indicated how it may be extended to the infinite tower of higher spins. Interactions are not considered. The procedure is the same that was employed recently for the spin(3/2,2) multiplet of supergravity. One introduces new potentials ("prepotentials") by solving the constraints of the Hamiltonian formulation. In terms of the prepotentials, the action is written in a form in which its electricmagnetic duality invariance is manifest. The prepotential action is local, but the spacetime invariance is not manifest. Just as for the spin2 and spin(3/2,2) cases, the gauge symmetries of the prepotential action take a form similar to those of the free conformal theory of the same multiplet. The automatic emergence of gauge conformal invariance out of demand of manifest duality invariance, is yet another evidence of the subtle interplay between duality invariance and spacetime symmetry. We also compare and contrast the formulation with that of the analogous spin(1,3/2) multiplet.06/2014;  [Show abstract] [Hide abstract]
ABSTRACT: Threedimensional spacetime with a negative cosmological constant has proven to be a remarkably fertile ground for the study of gravity and higher spin fields. The theory is topological and, since there are no propagating field degrees of freedom, the asymptotic symmetries become all the more crucial. For pure (2+1) gravity they consist of two copies of the Virasoro algebra. There exists a black hole which may be endowed with all the corresponding charges. The pure (2+1) gravity theory may be reformulated in terms of two ChernSimons connections for sl(2,R). An immediate generalization containing gravity and a finite number of higher spin fields may be achieved by replacing sl(2,R) by sl(3,R) or, more generally, by sl(N,R). The asymptotic symmetries are then two copies of the socalled W_N algebra, which contains the Virasoro algebra as a subalgebra. The question then arises as to whether there exists a generalization of the standard pure gravity (2+1) black hole which would be endowed with all the W_N charges. The original pioneering proposal of a black hole along this line for N=3 turns out, as shown in this paper, to actually belong to the so called "diagonal embedding" of sl(2,R) in sl(3,R), and it is therefore endowed with charges of lower rather than higher spins. In contradistinction, we exhibit herein the most general black hole which belongs to the "principal embedding". It is endowed with higher spin charges, and possesses two copies of W_3 as its asymptotic symmetries. The most general diagonal embedding black hole is studied in detail as well, in a way in which its lower spin charges are clearly displayed. The extension to N>3 is also discussed. A general formula for the entropy of a generalized black hole is obtained in terms of the onshell holonomies.Journal of High Energy Physics 04/2014; 2014(5). · 5.62 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We investigate the cubic interactions of a massless higherspin fermion with gravity in flat space and present covariant 2ss vertices, compatible with the gauge symmetries of the system, preserving parity. This explicit construction relies on the BRST deformation scheme that assumes locality and Poincare invariance. Consistent nontrivial cubic deformations exclude minimal gravitational coupling and may appear only with a number of derivatives constrained in a given range. Derived in an independent manner, our results do agree with those obtained from the lightcone formulation or inspired by string theory. We also show that none of the Abelian vertices deform the gauge transformations, while all the nonAbelian ones are obstructed in a local theory beyond the cubic order.Journal of High Energy Physics 10/2013; 2014(1). · 5.62 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We indicate how to introduce chemical potentials for higher spin charges in higher spin antide Sitter gravity in a manner that manifestly preserves the original asymptotic Wsymmetry. This is done by switching on a nonvanishing component of the connection along the temporal (thermal) circles. We first recall the procedure in the pure gravity case (no higher spin) where the only "chemical potentials" are the temperature and the chemical potential associated with the angular momentum. We then generalize to the higher spin case. We find that there is no tension with the W(N) or W(infinity) asymptotic algebra, which is obviously unchanged by the introduction of the chemical potentials. Our argument is nonperturbative.Journal of High Energy Physics 09/2013; 2013(12). · 5.62 Impact Factor  Physical Review D 09/2013; 88(6). · 4.69 Impact Factor

Article: Sources for Generalized Gauge Fields
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ABSTRACT: Generalized gauge fields are tensor fields with mixed symmetries. For gravity and higher spins in dimensions greater than four, the fundamental field in the "magnetic representation" is a generalized gauge field. It is shown that the analog of a point source for a generalized gauge field is a special type of brane whose worldsheet has another brane interwoven into it: a current within a current. In the case of gravity in higher dimensions, this combined extended object is the generalization of a magnetic pole. The Dirac quantization condition for the "electric" and "magnetic" strengths holds.Physical Review D 08/2013; 88(8). · 4.69 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: Interactions of gaugeinvariant systems are severely constrained by several consistency requirements. One is the preservation of the number of gauge symmetries, another is causal propagation. For lowerspin fields, the emphasis is usually put on gauge invariance that happens to be very selective by itself. We demonstrate with an explicit example, however, that gauge invariance, albeit indispensable for constructing interactions, may not suffice as a consistency condition. The chosen example that exhibits this feature is the theory of a massless spin3/2 field coupled to electromagnetism. We show that this system admits an electromagnetic background in which the spin3/2 gauge field may move faster than light. Requiring causal propagation rules out otherwise allowed gaugeinvariant couplings. This emphasizes the importance of causality analysis as an independent test for a system of interacting gauge fields. We comment on the implications of allowing new degrees of freedom and nonlocality in a theory, on higherderivative gravity and Vasiliev's higherspin theories.Physical review D: Particles and fields 06/2013; 88(6).  [Show abstract] [Hide abstract]
ABSTRACT: The linearized Einstein equations in D spacetime dimensions can be written as twisted selfduality equations expressing that the linearized curvature tensor of the graviton described by a ranktwo symmetric tensor, is dual to the linearized curvature tensor of the "dual graviton" described by a tensor of (D3,1) Young symmetry type. In the case of 4 dimensions, both the graviton and its dual are ranktwo symmetric tensors (Young symmetry type (1,1)), while in the case of 11 spacetime dimensions relevant to Mtheory, the dual graviton is described by a tensor of (8,1) Young symmetry type. We provide in this paper an action principle that yields the twisted selfduality conditions as equations of motion, keeping the graviton and its dual on equal footing. In order to construct a local, quadratic, variational principle for the twisted linear selfduality equations, it is necessary to introduce two "prepotentials". These are also tensors of mixed Young symmetry types and are obtained by solving the Hamiltonian constraints of the Hamiltonian formulation either of the PauliFierz action for the graviton or of the Curtright action for its dual, the resulting actions being identical. The prepotentials enjoy interesting gauge invariance symmetries, which are exhibited and generalize the gauge symmetries found in D=4. A variational principle where the basic variables are the original PauliFierz field and its dual can also be given but contrary to the prepotential action, the corresponding action is nonlocal in space  while remaining local in time. We also analyze in detail the Hamiltonian structure of the theory and show that the graviton and its dual are canonically conjugate in a sense made precise in the text.Physical review D: Particles and fields 06/2013; 88(6).  [Show abstract] [Hide abstract]
ABSTRACT: A formulation of linearized gravity which is manifestly invariant under electricmagnetic duality rotations in the internal space of the metric and its dual, and which contains both metrics as basic variables (rather than the corresponding prepotentials), is derived. In this bimetric formulation, the variables have a more immediate geometrical significance, but the action is nonlocal in space, contrary to what occurs in the prepotential formulation. More specifically, one finds that: (i) the kinetic term is nonlocal in space (but local in time); (ii) the Hamiltonian is local in space and in time; (iii) the variables are subject to two Hamiltonian constraints, one for each metric.01/2013;  [Show abstract] [Hide abstract]
ABSTRACT: We consider all possible dynamical theories which evolve two transverse vector fields out of a threedimensional Euclidean hyperplane, subject to only two assumptions: (i) the evolution is local in space, and (ii) the theory is invariant under "duality rotations" of the vector fields into one another. The commutators of the Hamiltonian and momentum densities are shown to be necessarily those of the Poincaré group or its zero signature contraction. Spacetime structure thus emerges out of the principle of duality.Physical Review Letters 01/2013; 110(1):011603. · 7.73 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: The concept of electricmagnetic duality can be extended to linearized gravity. It has indeed been established that in four dimensions, the PauliFierz action (quadratic part of the EinsteinHilbert action) can be cast in a form that is manifestly invariant under duality rotations in the internal 2plane of the spacetime curvature and its dual. In order to achieve this manifestly dualityinvariant form, it is necessary to introduce two "prepotentials", which form a duality multiplet. These prepotentials enjoy interesting gauge invariance symmetries, which are, for each, linearized diffeomorphisms and linearized Weyl rescalings. The purpose of this note is twofold: (i) To rewrite the manifestlyduality invariant action obtained in previous work in a way that makes its gauge invariances also manifest. (ii) To explicitly show that the equations of motion derived from that action can be interpreted as twisted selfduality conditions on the curvature tensors of the two metrics obtained from the two prepotentials.Journal of Physics A Mathematical and Theoretical 07/2012; 46(21). · 1.77 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: For the free massless spinone and spintwo field theories one may write the action in a form which is manifestly invariant under electricmagnetic duality. This is achieved by introducing new potentials through solving the constraints of the Hamiltonian formulation. The price for making electricmagnetic duality invariance manifest through this direct procedure is losing manifest Lorentz invariance. Both theories admit supersymmetric extensions, which make the bosonic fields and their corresponding fermionic partners to be parts of the same geometrical object, a supermultiplet. We present in this paper the supersymmetric extension of the manifestly electricmagnetic duality invariant actions for the photon and the photino; and for the graviton and the gravitino. In each case the spinor fields transform under electricmagnetic duality in a chiral manner. For the spintreehalf field, which possesses a gauge invariance, it is necessary to bring in a spinor "prepotential". As in previous cases the introduction of additional potentials to solve the constraints increases the number of gauge invariances of the action, thus keeping the number of degrees of freedom unaltered. The similarity in the formulations for the photonphotino and gravitongravitino systems is remarkable.Physical review D: Particles and fields 07/2012; 86(6).  [Show abstract] [Hide abstract]
ABSTRACT: We study the electromagnetic coupling of massless higherspin fermions in flat space. Under the assumptions of locality and Poincare invariance, we employ the BRSTBV cohomological methods to construct consistent paritypreserving offshell cubic 1ss vertices. Consistency and nontriviality of the deformations not only rule out minimal coupling, but also restrict the possible number of derivatives. Our findings are in complete agreement with, but derived in a manner independent from, the lightconeformulation results of Metsaev and the stringtheoryinspired results of SagnottiTaronna. We prove that any gaugealgebrapreserving vertex cannot deform the gauge transformations. We also show that in a local theory, without additional dynamical higherspin gauge fields, the nonabelian vertices are eliminated by the lack of consistent secondorder deformations.Journal of High Energy Physics 06/2012; 2012(8). · 5.62 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We consider (2+1)dimensional (N, M)extended higherspin antide Sitter supergravity and study its asymptotic symmetries. The theory is described by the ChernSimons action based on a real, infinitedimensional higherspin superalgebra. We specify consistent boundary conditions on the higherspin supergauge connection corresponding to asymptotically antide Sitter spacetimes. We then determine the residual gauge transformations that preserve these asymptotic conditions and compute their Poisson bracket algebra. We find that the asymptotic symmetry is enhanced from the higherspin superalgebra to some (N,M)extended superW(infinity) nonlinear superalgebra. The latter has the same classical central charge as pure Einstein gravity. Special attention is paid to the (1,1)case. Truncation to the bosonic sector yields the previously found W(infinity) algebra, while truncation to the underlying finitedimensional superalgebra reproduces the Nextended superconformal algebra (in its nonlinear version for N>2). We discuss string theory realization of these higherspin antide Sitter supergravity theories as well as relations to previous treatments of superW(infinity) in the literature.03/2012;  [Show abstract] [Hide abstract]
ABSTRACT: We consider the relation between higher spin gauge fields and real KacMoody Lie algebras. These algebras are obtained by double and triple extensions of real forms g_0 of the finitedimensional simple algebras g arising in dimensional reductions of gravity and supergravity theories. Besides providing an exhaustive list of all such algebras, together with their associated involutions and restricted root diagrams, we are able to prove general properties of their spectrum of generators with respect to a decomposition of the triple extension of g_0 under its gravity subalgebra gl(D,R). These results are then combined with known consistent models of higher spin gauge theory to prove that all but finitely many generators correspond to nonpropagating fields and there are no higher spin fields contained in the KacMoody algebra.General Relativity and Gravitation 10/2011; 44(7). · 1.90 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: Asymptotically warped AdS spacetimes in topologically massive gravity with negative cosmological constant are considered in the case of spacelike stretched warping, where black holes have been shown to exist. We provide a set of asymptotic conditions that accommodate solutions in which the local degree of freedom (the "massive graviton") is switched on. An exact solution with this property is explicitly exhibited and possesses a slower falloff than the warped AdS black hole. The boundary conditions are invariant under the semidirect product of the Virasoro algebra with a u(1) current algebra. We show that the canonical generators are integrable and finite. When the graviton is not excited, our analysis is compared and contrasted with earlier results obtained through the covariant approach to conserved charges. In particular, we find agreement with the conserved charges of the warped AdS black holes as well as with the central charges in the algebra.Physical Review D 08/2011; 84. · 4.69 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: Recently, the concept of dynamical extended charged events has been introduced, and it has been argued that they should play as central a role as that played by particles or ordinary branes. In this article we show that in the presence of a ChernSimons coupling, a magnetically charged extended event emits an extended object, which geometrically is just like a Dirac string, but it is observable, obeys equations of motion, and may be electrically charged. We write a complete action principle which accounts for this effect. The action involves two ChernSimons terms, one integrated over spacetime and the other integrated over the worldvolume of the submanifold that is the union of the Dirac worldsheet and the history of the emitted physical object. By demanding that the total charge emitted by a composite extended magnetic event be quantized according to Dirac's rule, we find a quantization condition for the ChernSimons coupling. For a 1form electric potential in D=2n+1 spacetime dimensions, the composite event is formed by n elementary extended magnetic events separated in time such that the product of their transverse spaces, together with the time axis, is the entire spacetime. We show that the emitted electric charge is given by the integral of the (n1)th exterior power of the electromagnetic field strength over the last elementary event, or, equivalently, over an appropriate closed surface. The extension to more general pform potentials and higher dimensions is also discussed. For the case D=11, p=3, our result for the quantization of the ChernSimons coupling was obtained previously in the context of Mtheory, a remarkable agreement that makes the existence of events even more compelling.Physical review D: Particles and fields 08/2011; 84. 
Article: The Action for Twisted SelfDuality
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ABSTRACT: One may write the Maxwell equations in terms of two gauge potentials, one electric and one magnetic, by demanding that their field strengths should be dual to each other. This requirement is the condition of twisted selfduality. It can be extended to pforms in spacetime of D dimensions, and it survives the introduction of a variety of couplings among forms of different rank, and also to spinor and scalar fields, which emerge naturally from supergravity. In this paper we provide a systematic derivation of the action principle, whose equations of motion are the condition of twisted selfduality. The derivation starts from the standard Maxwell action, extended to include the aforementioned couplings, and proceeds via the Hamiltonian formalism through the resolution of Gauss' law. In the pure Maxwell case we recover in this way an action that had been postulated by other authors, through an ansatz based on an action given earlier by us for untwisted selfduality. Those authors also extended their ansatz to include ChernSimons couplings. In that case, we find a different result. The derivation from the standard extended Maxwell action implies of course that the theory is Lorentzinvariant and can be locally coupled to gravity. Nevertherless we include a direct compact Hamiltonian proof of these properties, which is based on the surfacedeformation algebra. The symmetry in the dependence of the action on the electric and magnetic variables is manifest, since they appear as canonical conjugates. Spacetime covariance, although present, is not manifest.Physical review D: Particles and fields 03/2011; 83.  [Show abstract] [Hide abstract]
ABSTRACT: It was established long ago that SO(2) electricmagnetic duality is an {\em offshell} symmetry of the free Maxwell theory, i.e., that it leaves invariant the action and not just the equations of motion. We review here that analysis and extend it to the Maxwell field coupled to scalar fields defined on the $SL(2,\mathbb{R})/SO(2)$ coset space, showing that $SL(2,\mathbb{R})$ is in that case an {\em offshell} symmetry. We also show how the result can be generalized to many Maxwell fields and $Sp(2n, \mathbb{R})$ duality symmetry  or a subgroup of it, recovering in particular the case of maximal supergravity in four dimensions with $E_{7,7}$ symmetry. We finally indicate further possible extensions to twisted selfduality equations for $p$forms, including ChernSimons terms and Pauli couplings, as well as linearized gravity, which will be treated in depth elsewhere.01/2011;  [Show abstract] [Hide abstract]
ABSTRACT: We consider the relation between higher spin gauge fields and real KacMoody Lie algebras. These algebras are obtained by double and triple extensions of real forms g_0 of the finitedimensional simple algebras g arising in dimensional reductions of gravity and supergravity theories. Besides providing an exhaustive list of all such algebras, together with their associated involutions and restricted root diagrams, we are able to prove general properties of their spectrum of generators w.r.t. a decomposition of the triple extension of g_0 under its gravity subalgebra gl(D,R). These results are then combined with known consistent models of higher spin gauge theory to prove that all but finitely many generators correspond to nonpropagating fields and there are no higher spin fields contained in the KacMoody algebra.01/2011;
Publication Stats
11k  Citations  
717.35  Total Impact Points  
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Institutions

2013

Max Planck Institute for Gravitational Physics (AlbertEinsteinInstitute)
Potsdam, Brandenburg, Germany


2012–2013

Universidad Andrés Bello
CiudadSantiago, Santiago, Chile


1985–2013

Centro de Estudios Cientificos (CECs)
Ciudad de Valdivía, Los Ríos, Chile


1970–2013

Université Libre de Bruxelles
 • Unit of Mathematical Physics
 • Nuclear Physics and Mathematical Physics Unit
 • Faculty of Sciences
Bruxelles, Brussels Capital Region, Belgium


2010

Ecole Normale Supérieure de Paris
 Laboratoire de Physique Théorique
Lutetia Parisorum, ÎledeFrance, France


2009

Chalmers University of Technology
 Department of Fundamental Physics
Göteborg, Vaestra Goetaland, Sweden


2007

California Institute of Technology
Pasadena, California, United States


2001

Institut des Hautes Études Scientifiques
BuresOrsay, ÎledeFrance, France


2000

University of California, Santa Barbara
 Kavli Institute for Theoretical Physics
Santa Barbara, CA, United States


1998

Brandeis University
Waltham, Massachusetts, United States


1997

University of Santiago, Chile
 Departamento de Física
CiudadSantiago, Santiago, Chile


1992

Pierre and Marie Curie University  Paris 6
Lutetia Parisorum, ÎledeFrance, France


1982–1989

University of Texas at Austin
Austin, Texas, United States


1983

University of Liège
 Department of Astrophysics, Geophysics and Oceanography
Liège, WAL, Belgium
