arXiv subjects

Annu Batra

Publications and source records attributed to Annu Batra.

4 recordsLinked to original sources

arXiv1999

Nucleosynhthesis in a Simmering Universe

Primordial nucleosynthesis is a success story of the standard big bang (SBB) cosmology. We explore nucleosynthesis in possible models very different from SBB in which the cosmological scale factor increases linearly with time right through the period during which nucleosynthesis occurs till the present.It turns out that weak interactions remain in thermal equilibrium upto temperatures which are two orders of magnitude lower than the corresponding (weak interaction decoupling) temperatures in SBB. Inverse beta decay of the proton ensures adequate production of helium while producing primordial metallicity much higher than that produced in SBB. Attractive features of such models are the absence of the horizon, flatness and age problems and consistency with classical cosmological tests.

nucl-th↗

arXiv1998

Nucleosynthesis in a simmering univeerse

Primordial nucleosynthesis is considered a success story of the standard big bang (SBB) cosmology. The cosmological and elementary particle physics parameters are believed to be severely constrained by the requirement of correct abundances of light elements. We explore nucleosynthesis in a class of models very different from SBB. In these models the cosmological scale factor increases linearly with time right through the period during which nucleosynthesis occurs till the present. It turns out that weak interactions remain in thermal equilibrium upto temperatures which are two orders of magnitude lower than the corresponding (weak interaction decoupling) temperature in SBB. Inverse beta decay of the proton can ensure adequate production of several light elements while producing primordial metalicity much higher than that produced in SBB. Other attractive features of these models are the absence of the horizon, flatness and the age problems and consistency with classical cosmological tests.

gr-qc↗

arXiv1996

Nucleosynthesis in a Simmering Universe

Primordial nucleosynthesis is considered a success story of the standard big bang (SBB) cosmology. The cosmological and elementary particle physics parameters are believed to be severely constrained by the requirement of correct abundances of light elements. We demonstrate nucleosynthesis in a class of models very different from SBB. In these models the cosmological scale factor increases linearly with time from the period during which nucleosynthesis occurs. It turns out that weak interactions remain in thermal equilibrium upto temperatures which are two orders of magnitude lower than the corresponding temperatures in SBB. Inverse beta decay of the proton can ensure adequate production of several light elements while producing primordial metallicity much higher than that produced in SBB. Other attractive features of these models are the absence of the horizon, flatness and initial singularity problems, consistency with the age of globular clusters and consistent relationships between redshift and luminosity distance, angular diameter distance and the galaxy number count.

astro-ph↗

arXiv1996

Studies in Structure Formation in theories with a repulsive long range gravitational force

This article reports on emergence of structures in a class of alternative theories of gravity. These theories do not have any horizon, flatness, initial cosmological singularity and (possibly) quantization problems. The model is characterised by a dynamically induced gravitational constant with a ``wrong'' sign corresponding to repulsive gravitation on the large scale. A non - minimal coupling of a scalar field in the model can give rise to non - topological solitons in the theory. This results in domains (gravity - balls) inside which an effective, canonical, attractive gravitational constant is induced. We consider simulations of the formation and evolution of such solutions. Starting with a single gravity - ball, we consider its fragmentation into smaller (lower mass) balls - evolving by mutual repulsion. After several runs, we have been able to identify two parameters: the strength of the long range gravitational constant and the size of the gravity balls, which can be used to generate appropriate two point correlations of the distribution of these balls.

gr-qc↗