Sudhakar Panda

Research Summary:

We studied a String theory inspired model for hybrid inflation in the context of a brane-antibrane system partially compactified on a compact submanifold of a Calabi-Yau manifold.Inthis scenario, the time dependent scalar field representing the interbrane separation plays the role of an inflaton field, whereas, the end of the inflationary epoch is brought about by the rapid rolling of the tachyon field. The number of e-foldings is sufficiently large and is controlled by the initial conditions. However, the slow-roll parameters are determined by the geometry. The primordial density fluctuation is found to be consistent with current observational data for reduced string scale. (work with D. Choudhury, D. Ghoshal and D.P. Jatkar).

We continued our investigation on De Sitter solution by analysing the scalar potential and mass-matrix of gauged N=4 supergravity with matter (with six matter multiplets), extending our previous work by including the dependence of all the scalars describing the scalar manifold of the theory. We considered various semi-simple groups for gauging and studied the corresponding potential, its first and second derivatives at the origin of the scalar manifold. For a number of gauge groups, we found extrema with positive cosmological constant. (work with M. deRoo, D. B. Westra and M. Trigiante).

Publications:

• Choudhury D., Ghoshal D, Jatkar D.P. and Panda S., Hybrid Inflation and Brane-Antibrane System, JCAP 07 (2003) 009.

• de Roo M., Panda S., Trigiante M. and Westra D.B., Potential and mass-matrix in gauged N=4 supergravity, JHEP 11 (2003) 022.

Preprints:

• Hybrid Inflation and Brane-antibrane system, D. Choudhury, D. Ghoshal, D.P. Jatkar and S. Panda, hep-th/0305104.

• Potential and mass-matrix in gauged N=4 supergravity, M. de Roo, S. Panda, D.B. Westra and M.Trigiante, hep-th/0310187.

Conference/Workshops Attended:

• Field Theory Aspects of Gravity, Pelling, Sikim India (2004).

• "Dirac Centenary Seminar" on Contemporary Trend in Physics, Sambalpur Univ. Orissa, India (2004).

Visits to other Institutes:

• TIFR, Mumbai (2003).

• University of Groningen, The Netherlands (2003).

• Abdus Salam ICTP, Trieste, Italy (2003)

• Sambalpur Univ, Orissa (2004).

Invited Lectures/Seminars:

• De Sitter Solution in four dimensional SUGRA Theory; TIFR, Mumbai.

• De Sitter solution in gauged N=4 supergravity; ICTP, Trieste.

• In Search of Unified Theory; Sambalpur University, Orissa.

Other Activities:

Taught Advanced Quantum Mechanics, 2nd Sem. Course at HRI.