patricio salgado | Duoc Uc (original) (raw)

Uploads

Papers by patricio salgado

Physics Letters B, 2003

A higher dimensional gravity invariant both under local Lorentz rotations and under local Anti de... more A higher dimensional gravity invariant both under local Lorentz rotations and under local Anti de Sitter boosts is constructed. It is shown that such a construction is possible both when odd dimensions and when even dimensions are considered. It is also proved that such actions have the same coefficients as those obtained in ref. .

Physics Letters B, 2009

Chern-Simons models for gravity are interesting because they provide with a truly gauge-invariant... more Chern-Simons models for gravity are interesting because they provide with a truly gauge-invariant action principle in the fiber-bundle sense. So far, their main drawback has largely been the perceived remoteness from standard General Relativity, based on the presence of higher powers of the curvature in the Lagrangian (except, remarkably, for threedimensional spacetime). Here we report on a simple model that suggests a mechanism by which standard General Relativity in five-dimensional spacetime may indeed emerge at a special critical point in the space of couplings, where additional degrees of freedom and corresponding "anomalous" Gauss-Bonnet constraints drop out from the Chern-Simons action. To achieve this result, both the Lie algebra g and the symmetric g-invariant tensor that define the Chern-Simons Lagrangian are constructed by means of the Lie algebra S-expansion method with a suitable finite abelian semigroup S. The results are generalized to arbitrary odd dimensions, and the possible extension to the case of eleven-dimensional supergravity is briefly discussed.

We propose an outgrowth of the expansion method introduced by de Azcárraga et al. [Nucl. Phys. B ... more We propose an outgrowth of the expansion method introduced by de Azcárraga et al. [Nucl. Phys. B 662 (2003) 185]. The basic idea consists in considering the direct product between an abelian semigroup S and a Lie algebra g. General conditions under which relevant subalgebras can systematically be extracted from S ×g are given. We show how, for a particular choice of semigroup S, the known cases of expanded algebras can be reobtained, while new ones arise from different choices. Concrete examples, including the M algebra and a D'Auria-Fré-like Superalgebra, are

The expansion of a Lie algebra entails finding a new, bigger algebra G, through a series of well-... more The expansion of a Lie algebra entails finding a new, bigger algebra G, through a series of well-defined steps, from an original Lie algebra g. One incarnation of the method, the so-called Sexpansion, involves the use of a finite abelian semigroup S to accomplish this task. In this paper we put forward a dual formulation of the S-expansion method which is based on the dual picture of a Lie algebra given by the Maurer-Cartan forms. The dual version of the method is useful in finding a generalization to the case of a gauge free differential algebra, which in turn is relevant for physical applications in, e.g., Supergravity. It also sheds new light on the puzzling relation between two Chern-Simons Lagrangians for gravity in 2+1 dimensions, namely the Einstein-Hilbert Lagrangian and the one for the so-called '

Journal of Physics A-mathematical and Theoretical, 2012

We show that the so-called semi-simple extended Poincaré (SSEP) algebra in D dimensions can be ob... more We show that the so-called semi-simple extended Poincaré (SSEP) algebra in D dimensions can be obtained from the anti-de Sitter algebra by means of the S-expansion procedure with an appropriate semigroup S. A general prescription is given for computing Casimir operators for S-expanded algebras, and the method is exemplified for the SSEP algebra. The S-expansion method also allows us to

Journal of Physics: Conference Series, 2008

... through Abelian Semigroups Fernando Izaurieta, Eduardo Rodr´ıguez and Patricio Salgado Depart... more ... through Abelian Semigroups Fernando Izaurieta, Eduardo Rodr´ıguez and Patricio Salgado Departamento de Fısica, Universidad de Concepción, Casilla 160-C, Concepción, Chile E-mail: fizaurie@gmail.com, edurodriguez@udec.cl and pasalgad@udec.cl Abstract. ...

Letters in Mathematical Physics, 2007

In the context of Chern–Simons (CS) Theory, a subspace separation method for the Lagrangian is pr... more In the context of Chern–Simons (CS) Theory, a subspace separation method for the Lagrangian is proposed. The method is based on the iterative use of the Extended Cartan Homotopy Formula, and allows one to (1) separate the action in bulk and boundary contributions, and (2) systematically split the Lagrangian in appropriate reflection of the subspace structure of the gauge algebra. In order to apply the method, one must regard CS forms as a particular case of more general objects known as transgression forms. Five-dimensional CS Supergravity is used as an example to illustrate the method.

A transgression form is proposed as lagrangian for a gauge field theory. The construction is firs... more A transgression form is proposed as lagrangian for a gauge field theory. The construction is first carried out for an arbitrary Lie Algebra g and then specialized to some particular cases. We exhibit the action, discuss its symmetries, write down the equations of motion and the boundary conditions that follow from it, and finally compute conserved charges. We also present a method, based on the iterative use of the Extended Cartan Homotopy Formula, which allows one to (i) systematically split the lagrangian in order to appropriately reflect the subspaces structure of the gauge algebra, and (ii) separate the lagrangian in bulk and boundary contributions. Chern-Simons Gravity and Supergravity are then used as examples to illustrate the method. In the end we discuss some further theoretical implications that arise naturally from the mathematical structure being considered.

European Physical Journal C, 2008

A new Lagrangian realizing the symmetry of the M-algebra in eleven-dimensional space-time is pres... more A new Lagrangian realizing the symmetry of the M-algebra in eleven-dimensional space-time is presented. By means of the novel technique of Abelian semigroup expansion, a link between the M-algebra and the orthosymplectic algebra mathfrakosp(32∣1)\mathfrak{osp}(32|1)mathfrakosp(32∣1) is established, and an M-algebra-invariant symmetric tensor of rank six is computed. This symmetric invariant tensor is a key ingredient in the construction of the new Lagrangian. The gauge-invariant Lagrangian is displayed in an explicitly Lorentz-invariant way by means of a subspace separation method based on the extended Cartan homotopy formula.

Physics Letters B, 2004

In the context of a gauge theoretical formulation, higher dimensional gravity invariant under the... more In the context of a gauge theoretical formulation, higher dimensional gravity invariant under the AdS group is dimensionally reduced to Euler-Chern-Simons gravity. The dimensional reduction procedure of Grignani-Nardelli [Phys. Lett. B 300, 38 (1993)] is generalized so as to permit reducing D-dimensional Lanczos Lovelock gravity to d = D − 1 dimensions.

European Physical Journal C, 2004

In the context of the formalism proposed by Stelle-West and Grignani-Nardelli, it is shown that C... more In the context of the formalism proposed by Stelle-West and Grignani-Nardelli, it is shown that Chern-Simons supergravity can be consistently obtained as a dimensional reduction of (3 + 1)dimensional supergravity, when written as a gauge theory of the Poincarè group. The dimensional reductions are consistent with the gauge symmetries, mapping (3 + 1)-dimensional Poincarè supergroup gauge transformations onto (2 + 1)-dimensional Poincarè supergroup ones.