NEW TRENDS IN QUANTUM GRAVITY II

PROGRAM

	TUESDAY 8	WEDNESDAY 9	THURSDAY 10	FRIDAY 11
10:00 - 11:00	C.Herzog	A.Zee	C.Herzog	10-10:45 H.Girotti
11:00 - 11:15	coffee break	coffee break	coffee break	10:45-11 coffee break
11:15 - 12:15	C.Herzog	A.Zee	C.Herzog	11-11:45 P.Mora
12:15 - 13:00	J.Zanelli	discussion	J.Alfaro	11:45-12:30 N.Hatcher
13:00 - 15:00	lunch	lunch	lunch	lunch
15:00 - 15:45	C.Nunez	C.Herzog	G.Aldazabal
16:00 - 16:45	A.Queiroz	C.Herzog	J.Gamboa
16:45 - 17:15	coffee break	coffee break	coffee break
17:15 - 18:00	M.Reisenberger	F.Toppan	discussion

• G. Aldazabal (C. A. Bariloche) - String compactifications, fluxes and supergravity



• J. Alfaro (PUC, Chile) - Gauge invariant non-linear electrodynamics motivated by a spontaneous breaking of the Lorentz symmetry
We introduce a new version of non-linear electrodynamics which is produced by a spontaneous symmetry breaking of Lorentz invariance induced by the non-zero expectation value of the gauge invariant electromagnetic field strength. All possible choices of the vacuum lead only to the remaining invariant subgroups T(2) and HOM(2). We explore in detail the plane wave solutions of the linearized sector of the model for an arbitrary vacuum. They present two types of dispersion relations. One is the usual one, with fields similar to the Maxwell fields. The other dispersion relation involves anisotropies determined by the structure of the vacuum. The corresponding fields reflect these anisotropies.Finally, we speculate on the relation of the vacuum energy of the model with the cosmological constant and propose a connection between the vacuum fields and the intergalactic magnetic fields.


• J. Gamboa (U. Santiago Chile) - Towards a Theory of Bose-Einstein Condensation for any Integer Spin
A Bose-Einstein condensation theory for any integer spin by using noncommutative quantum mechanics methods is proposed. The generalized Gross-Pitaevskii equations are found and applied to several recent experiments with ultra-cold atoms. New possible experiments are also discussed.


• H. O. Girotti (UFRGS) - Noncommutative vs gravity
We review the classical dynamics emerging from the model underlying noncommutative quantum mechanics. Of particular interest are the cases of the Kepler and the two dimensional harmonic oscillator potentials. Orbital precession occurs. By making contact with results arising from General Relativity one can obtain estimates for the parameter associated with the noncommutativity. These estimates can be analyzed at the light of the uncertainty relation deriving from the equal-time commutator involving two position observables. This allows to discuss the issue of localization and its implications.


• N. Hatcher (U. Simon Bolivar) - The uses of superprojectors
We review how to construct projectors to irreducible supermultiplets in different dimensions and different extensions of supersymmetry. We use these superprojectors to build field equations and supersymmetric Lagrangians and to find new convariant quatizations of Brink-Schwarz superparticles.


• C. Herzog (Princeton U.) - How to get a superconductor out of a black hole



• P. Mora (U. Republica) - Chern-Simons Extended Objects and the Green-Schwarz Superstring Action
Chern-Simons supersymmetric branes can be regarded as generalisations of Dixon-Duff-Sezgin heterotic branes (describing the gauge invariant coupling of extended objects and gauge fields) for space-time groups and Chern-Simons Gravities. The requirement of gauge invariance leads from the use of Chern-Simons to Transgression forms. It is possible to obtain the Green-Schwarz Superstring action from a model of this class, thus embedding that action in a gauge invariant and background independent framework. I will discuss the motivation for and some properties of Chern-Simons branes and their connections with other models.


• C. Nunez (IAFE and Universidad de Buenos Aires) - String theory on AdS3 and AdS3/CFT2
I review some recent results on fusion rules and correlation functions in the AdS3-WZNW model and their application to string theory on AdS3. I discuss some open problems in this theory and in the AdS3/CFT2 correspondence.


• A. Queiroz (UnB) - Holographic QCD in an Inflationary Braneworld Scenario
The scenario we consider is an (Euclidean) inflating braneworld AdS_4 embedded in a static Euclidean AdS_5. Our goal is to study aspects of QCD during inflation period using techniques of gauge/gravity duality. We first study heavy-quark potential in this inflationary braneworld scenario. Using gauge/gravity duality we obtain a confining phase depending on the ratio between the Hubble parameter H in the braneworld and the brane tension sigma. Next we start to study mesons in an extension of this scenario to 10D, in order to embed it in a string-theoretical framework. In this extended scenario, we consider a spinning open string attached to a stack of D7-branes (flavor branes). We then give some perspectives on the phenomenology of mesons, in particular mesons decays. Besides a rich phenomenology, this work is an example of AdS/QCD in a time dependent background.


• M. Reisenberger (U. República) - Canonical gravity without constraints
Free (unconstrained) initial data for general relativity on a pair of intersecting null hypersurfaces are well known, but the lack of a Poisson bracket and concerns about caustics have stymied the development of a constraint free canonical theory. I describe how caustics and generator crossings can be neatly avoided and a Poisson bracket on free data is presented. This work is part of an effort to understand the holographic principle of 't Hooft.


• Francesco Toppan (CBPF) - Supersymmetric Extensions of Hopf Maps



• J. Zanelli (CECS) - Chern-Simons branes in AdS spaces
Branes are naked singularities analogous to linear or planar defects in crystals. Zero-branes in AdS spacetimes are "negative mass black holes", which can be generalized to higher-dimensional branes. When these solutions are endowed with angular momentum, the extremal spinning branes correspond to BPS states.


• A. Zee (KITP, Santa Barbara) - Gravity as a field theory