Ghanashyam Date, Institute of Mathematical Sciences, Chennai, INDIA
shyam@imsc.res.in
The fifth conference in the ICGC series, ICGC-2004, was
organized by the Cochin University of Science and Technology
(CUSAT) at the
Riviera Suites on the outskirts of Cochin
during January 5-10, 2004. It had 17 plenary talks and, as a new feature,
it also had 8 short talks which were more specialized than the plenary
talks but still accessible to a wider audience. There were three focus
themes: Cosmology, Gravitational Waves and Quantum Gravity.
About 70 contributed papers were presented in oral presentations and
poster sessions in four workshops on: Quantum
Aspects of Gravitation, Classical Aspects of Gravitation, Cosmology
and Gravitational waves and Relativistic astrophysics.
Cosmology: Robert Crittenden summarized the WMAP results
and Manoj Kaplighat discussed the early re-ionization aspect.
Jerry Ostriker gave a status summary of the `standard model' of cosmology
and emphasized the need and role of various complementary observations in
building up a comprehensive picture of cosmology. Looking some what into
the future, Subhabrata Majumdar discussed cluster surveys while
Bhuvnesh Jain discussed weak lensing. Finally, Robert
Crittenden doubled up for Edmund Copeland and surveyed a variety
of theoretical ideas being pursued, some quite desperate, regarding an
understanding of the Dark Energy.
Gravitational Waves: Talks in this theme covered various
aspects from analytical and numerical computations of wave forms to
interesting design aspects of interferometric detectors.
Gabriela González described the LIGO
experiment and the science runs. Vicky Kalogera discussed the
event rate estimations from compact binaries. Detector assembly
integration and simulations were discussed by Biplab Bhawal while
Sanjeev Dhurandhar discussed in detail data
analysis strategies required to construct efficient and effectual
templates for gravitational wave detection.
The analytical computations of the chirps within the PN
expansion framework was discussed by Luc Blanchet. Masaru
Shibata provided the current status and an optimistic future of numerical
simulations using supercomputers. Frederic Rasio discussed the
possibility of constraining the equation of state for neutron stars from
observations of gravitational wave forms.
Quantum Gravity: In this theme there was one talk on string
QG, two on loop QG, two on black hole entropy in various approaches,
one on brane cosmology and one on phenomenological QG. Sandip
Trivedi described the recent advances in getting not one but a very
large number (
) of De Sitter vacua in string theory. This
is achieved by a controlled SUSY breaking in a compactification with fluxes.
Jorge Pullin briefly described the main historical steps in the
loop quantum gravity program and then focused on the recent proposal of
a priori discretization of space-time.
In a discrete time formulation,
the evolution is achieved by finite canonical transformations. For a
constraint theory, this allows one to obtain a constraint-free
formulation. Various implications were discussed.
Martin Bojowald
detailed the loop quantum cosmology framework and presented interesting recent
results. Saurya Das presented a fairly comprehensive comparison of
the calculation of black hole entropy in various approaches such as
strings, LQG, horizon CFT, AdS/CFT etc. including the logarithmic
corrections. He also discussed the attempts to understand the Hawking effect
and the information loss issue. Parthasarathi Majumdar discussed the
universality of canonical entropy including logarithmic corrections.
Brane cosmology, particularly the possibility of inflation being
driven by a scalar field propagating in the bulk as well, was discussed
by Misao Sasaki. Jorge Pullin summarized the attempts to look
for QG signals via Lorentz invariance-violating modifications of the
dispersion relations.
Other talks: Apart from the talks devoted to the main
themes, there were five talks dealing with different aspects of
gravitation. Clifford Will summarized the current limits on the
various parameters from the traditional tests of GR and also discussed
newer possibilities from gravitational waves. Gravitational collapse and
the status of naked singularities was summarized by Tomohiro
Harada. Patrick Das Gupta discussed the so called `short'
duration GRB's and their statistics. Sayan Kar discussed the issue
of quantification of `small' violations of the averaged energy condition
and its role in traversable worm holes. The classic topic of `Kerr-Schild
geometries' was discussed by Roy Kerr. Ghanashyam Date
gave an over view of the conference.
There was also an `outreach lecture' by Clifford Will on
``Was Einstein Right?" for the undergraduate students in a city
college. The otherwise intense atmosphere of the conference was
lightened by a delightful pre-dinner talk by C. V. Vishveshwara
titled: ``Cosmos in Cartoons".
The conference had a half-a-day `cultural session' consisting of a
backwater cruise, the traditional classical dance of Kathakali
(narration of stories through dance) and the, unique to Kerala,
twelfth-century martial arts called Kalaripayat followed by the
conference banquet.
After this memorable experience, one looks forward to future
ICGC meetings.
Links to presentation as pdf/ppt/ps files can be soon found at
Presentation (pdf/ppt/ps files) will soon be available at
http://meghnad.iucaa.ernet.in/~iagrg/talks.html.
The proceedings of the conference will be published as a special issue
of Pramana - Journal of Physics.
The conference was sponsored by: The Abdus Salam ICTP, Italy; BRNS
(DAE), Mumbai; CSIR, New Delhi; DST, New Delhi; HRI, Allahabad; IIA,
Bangalore; ISRO, Bangalore; IMSc, Chennai; IOP, UK; IUCAA, Pune; RRI,
Bangalore and UGC, New Delhi.
Jorge Pullin
2004-03-12