International Conference on Gravitation and Cosmology 2004

Ghanashyam Date, Institute of Mathematical Sciences, Chennai, INDIA
The International Conference on Gravitation and Cosmology is a series of conferences held approximately every four years in India. The series has been conceived as a means to provide younger researchers an exposure to latest research trends and to promote interaction between the International and the Indian research communities. Each of these conferences focuses on two or three `theme topics' and are typically attended by about a 100 participants from India and abroad. The previous conferences in this series were held at Goa (1987), Ahmedabad (1991), Pune (1995) and Kharagpur (2000) and have been quite successful in the stated objectives.

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 ($\sim 10^{100}$) 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

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