## Person: Garay Elizondo, Luis Javier

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##### First Name

Luis Javier

##### Last Name

Garay Elizondo

##### Affiliation

Universidad Complutense de Madrid

##### Faculty / Institute

Ciencias Físicas

##### Department

Física Teórica

##### Area

Física Teórica

##### Identifiers

5 results

## Search Results

Now showing 1 - 5 of 5

Publication Black holes turn white fast, otherwise stay black: no half measures(Springer, 2016-01-26) Barceló, Carlos; Carballo Rubio, Raúl; Garay Elizondo, Luis JavierRecently, various authors have proposed that the dominant ultraviolet effect in the gravitational collapse of massive stars to black holes is the transition between a black-hole geometry and a white-hole geometry, though their proposals are radically different in terms of their physical interpretation and characteristic time scales [1, 2]. Several decades ago, it was shown by Eardley that white holes are highly unstable to the accretion of small amounts of matter, being rapidly turned into black holes [3]. Studying the crossing of null shells on geometries describing the black-hole to white-hole transition, we obtain the conditions for the instability to develop in terms of the parameters of these geometries. We conclude that transitions with long characteristic time scales are pathologically unstable: occasional perturbations away from the perfect vacuum around these compact objects, even if being imperceptibly small, suffocate the white-hole explosion. On the other hand, geometries with short characteristic time scales are shown to be robust against perturbations, so that the corresponding processes could take place in real astrophysical scenarios. This motivates a conjecture about the transition amplitudes of different decay channels for black holes in a suitable ultraviolet completion of general relativity.Publication Emergent gauge symmetries: Yang-Mills theory(Springer, 2021-05-02) Barceló, Carlos; Carballo Rubio, Raúl; Garay Elizondo, Luis Javier; García Moreno, GerardoIn this article, subleading (in 1/N) corrections to the action of the one loop dilatation operator in the su(3) sector of N = 4 super Yang-Mills theory are studied. We focus on the system of operators dual to two giant graviton systems, which have a bare dimension ∼ O(N) and are a linear combination of restricted Schur polynomials with p = 2 long columns. At the leading order the dilatation operator gives rise to the free part of an emergent Yang-Mills theory, arising from the open string excitations of the giant gravitons. We verify that the terms we study describe interactions between these open string excitations. The interactions have the U(1)×U(1) gauge invariance expected for a pair of separated branes.Publication From physical symmetries to emergent gauge symmetries(Springer, 2016-10-17) Barceló, Carlos; Carballo Rubio, Raúl; Di Filippo, Francesco; Garay Elizondo, Luis JavierGauge symmetries indicate redundancies in the description of the relevant degrees of freedom of a given field theory and restrict the nature of observable quantities. One of the problems faced by emergent theories of relativistic fields is to understand how gauge symmetries can show up in systems that contain no trace of these symmetries at a more fundamental level. In this paper we start a systematic study aimed to establish a satisfactory mathematical and physical picture of this issue, dealing first with abelian field theories. We discuss how the trivialization, due to the decoupling and lack of excitation of some degrees of freedom, of the Noether currents associated with physical symmetries leads to emergent gauge symmetries in specific situations. An example of a relativistic field theory of a vector field is worked out in detail in order to make explicit how this mechanism works and to clarify the physics behind it. The interplay of these ideas with well-known results of importance to the emergent gravity program, such as the Weinberg-Witten theorem, are discussed.Publication Unimodular gravity and general relativity from graviton self-interactions(American Physical Society, 2014-06-16) Barceló, Carlos; Carballo Rubio, Raúl; Garay Elizondo, Luis JavierIt is commonly accepted that general relativity is the only solution to the consistency problem that appears when trying to build a theory of interacting gravitons (massless spin-2 particles). Padmanabhan’s 2008 thought-provoking analysis raised some concerns that are having resonance in the community. In this paper we present the self-coupling problem in detail and explicitly solve the infinite-iterations scheme associated with it for the simplest theory of a graviton field, which corresponds to an irreducible spin-2 representation of the Poincaré group. We make explicit the nonuniqueness problem by finding an entire family of solutions to the self-coupling problem. Then we show that the only resulting theory which implements a deformation of the original gauge symmetry happens to have essentially the structure of unimodular gravity. This makes plausible the possibility of a natural solution to the first cosmological constant problem in theories of emergent gravity. Later on, we change for the sake of completeness the starting free-field theory to Fierz-Pauli theory, an equivalent theory but with a larger gauge symmetry. We indicate how to carry out the infinite summation procedure in a similar way. Overall, we conclude that as long as one requires the (deformed) preservation of internal gauge invariance, one naturally recovers the structure of unimodular gravity or general relativity but in a version that explicitly shows the underlying Minkowski spacetime, in the spirit of Rosen’s flat-background bimetric theory.Publication Gravitational wave echoes from macroscopic quantum gravity effects(Springer, 2017-05-10) Barceló, Carlos; Carballo Rubio, Raúl; Garay Elizondo, Luis JavierNew theoretical approaches developed in the last years predict that macroscopic quantum gravity effects in black holes should lead to modifications of the gravitational wave signals expected in the framework of classical general relativity, with these modifications being characterized in certain scenarios by the existence of dampened rep-etitions of the primary signal. Here we use the fact that non-perturbative corrections to the near-horizon external geometry of black holes are necessary for these modifications to exist, in order to classify different proposals and paradigms with respect to this criterion and study in a neat and systematic way their phenomenology. Proposals that lead naturally to the existence of echoes in the late-time ringdown of gravitational wave signals from black hole mergers must share the replacement of black holes by horizonless configurations with a physical surface showing reflective properties in the relevant range of frequencies. On the other hand, proposals or paradigms that restrict quantum gravity effects on the external geometry to be perturbative, such as black hole complementarity or the closely related firewall proposal, do not display echoes. For the sake of completeness we exploit the interplay between the timescales associated with the formation of firewalls and the mechanism behind the existence of echoes in order to conclude that even unconventional distortions of the firewall concept (such as naked firewalls) do not lead to this phenomenon.