Carmen Nuñez, IAFE, Buenos Aires

carmen@iafe.uba.ar

The second edition of the Quantum Gravity in the Southern Cone workshop was held at the Centro Atómico Bariloche, Argentina on January 7-10, 1998. It brought together 50 researchers from South America as well as experts from the northern hemisphere, working on different aspects of quantum gravity and related topics. The plenary lectures enabled the participants to obtain a global picture of the status of the field in the various approaches. The meeting was further enriched by poster sessions. The following list summarizes the topics covered by the lecturers.

* Canonical Quantum Gravity*

* J.Pullin* overviewed of the attempts to apply the rules of canonical
quantization to GR. He stressed the important role played by spin networks
and by Thiemann's Hamiltonian. The problems presented by this Hamiltonian
(it commutes on non diffeomorfism invariant states) were addressed by
* R. Gambini,* who reported on progress made to solve them.
Midi-superspace models of canonical quantum gravity were considered by
* C. Torre* who indicated that one can satisfactorily quantize quantum
parameterized field theories on a two-dimensional spacetime, but that the
quantization of such theories in higher dimensions is still an open problem.
A framework for modelling quantum gravitational collapse was discussed by
* K. Kuchar *who considered the canonical dynamics of matter shells.
Both the dynamics of the shell and of the surrounding spacetime were shown
to follow from a single variational principle.
By formulating GR as a theory of surfaces, * C. Kozameh* showed how to
construct a quantum spacetime using only Scri equipped with free functions
as the kinematical structure

* String theory and higher dimensional objects*

* J. Maldacena* discussed the large N limit of certain field theories
and its relation to gravity. In a similar context, * A. Schwimmer*
referred to N=1 (Seiberg) duality in field theory and its realization
through branes.
Phenomenological aspects of string theory were covered by * G.
Aldazabal* who discussed non-perturbative orbifold vacua.
Branes in supergravities, string theory and M theory were
discussed by * M. Cederwall*. * M. Henneaux* referred to dyons,
charge quantization and electric-magnetic duality for **p**-form theories in spacetime dimensions with arbitrary gauge invariant
self-interactions. * B. Carter* discussed the geometry of non null **p**
surfaces embedded in **n** dimensions. Electric 2 branes were presented by
* R. Aros*. * J. Zanelli* reviewed Chern-Simons supergravity in
dimensions, showing that they contain non trivial dynamics leading to
interesting classical solutions such as black holes, solitons, membranes,
etc.

* Black hole physics, semiclassical theories and cosmology*

In the context of a two dimensional exactly solvable model, *
J. Russo* outlined the construction of an S-matrix and showed that
black holes will radiate out an energy of Planck order, stabilizing
after a transitory period. A similar picture appears in 3+1 Einstein
gravity with spherical symmetry. * R. Bousso* discussed the
evaporation of Schwarzschild-De Sitter black holes including the
one-loop effective action. * B.Hu* addressed the problem of
fluctuations and backreaction in semiclassical cosmology and black
holes by presenting a complete history of the subject and conjectured
that a stochastic description in terms of Einstein-Langevin equation
becomes relevant at the Planck scale. Semiclassical theories were
also considered by * C. Molina-Paris* and * S. Ramsey*. *
H. Rubinstein *reviewed the status of the big bang standard model and
the latest data available from observations.

Sun Feb 8 20:46:09 EST 1998