Spectacular Role of Electron Correlation in the Hyperfine Interactions in 2D5/2^2D_{5/2} States in Alkaline Earth Ions

The low-lying n(=3,4,5)d $^2D_{5/2}$ states alkaline earth ions are of vital importance in a number of different physical applications. The hyperfine structure constants of these states are characterized by unusually strong electron correlation effects. Relativistic coupled-cluster theory has been employed to carry out {\it ab initio} calculations of these constants. The role of the all order core-polarization effects was found to be decisive in obtaining good agreement of the results of our calculations with accurate measurements. The present work is an apt demonstration of the power of the coupled-cluster method to cope with strongly interacting configurations.Comment: Submitted to Physical Review Letters, 3 figures and 5 table

Comparative studies of the magnetic dipole and electric quadrupole hyperfine constants for the ground and low lying excited states of ^{25}Mg^{+}

We have employed the relativistic coupled cluster theory to calculate the magnetic dipole and electric quadrupole hyperfine constants for the ground and low lying excited states of singly ionized magnesium. Comparison with experimental and the other theoretical results are done and predictions are also made for a few low lying excited states which could be of interest. We have made comparative studies of the important many body effects contributing to the hyperfine constants for the different states of the ion.Comment: 3 figures, Late

Observable signals in a string inspired axion-dilaton background and Randall-Sundrum scenario

Rotation angle of the plane of polarization of the distant galactic radio waves has been estimated in a string inspired axion-dilaton background. It is found that the axion,dual to the field strength of the second rank antisymmetric massless Kalb-Ramond field in the string spectrum, produces a wavelength independent optical rotation which is much larger than that produced by the dilaton. Detection of such rotation has been reported in some recent cosmological experiments. The observed value has been compared with our estimated theoretical value following various cosmological constraints. The effects of warped extra dimensions in a braneworld scenario on such an optical rotation have been investigated.Comment: 17 Pages, Latex, article revised, To appear in Physical Review

Relativistic and correlation effects in atoms

This review article deals with some case studies of relativistic and correlation effects in atomic systems. After a brief introduction to relativistic many-electron theory, a number of applications ranging from correlation energy to parity non-conservation in atoms are considered. There is a special emphasis on relativistic coupled-cluster theory as most of the results presented here are based on it.Comment: Review article, 4 eps figures, latex 2

The Dutch East India Company through the Local Lens: Exploring the Dynamics of Indo-Dutch Relations in Seventeenth Century Bengal

Colonial and Global Histor

Keeping corruption at bay: A study of the VOC's administrative encounter with the Mughals in seventeenth-century Bengal

The VOC received complaints of corruption about its officials in Bengal. Accordingly, they sent a special committee to investigate its factories in this region in 1684. The committee’s reports exposed several illegal practices of the officials and the growth of Dutch nabobs who lived elite lifestyles under the Mughal administration in Bengal. Consequently, a few officials were charged with corruption and put to trial at the Company’s court. But instances of corrupt behaviour were not reduced in the subsequent years. What was the purpose of sending the committee then and what was the conduct that the VOC directors expected of their officials, both in the Dutch Republic and its factories in Mughal Bengal? This dissertation answers such questions by studying the committee’s operations in Bengal, located at the interface of two very different political settings: the Dutch Republic and the Mughal Empire. It concludes that the socio-political developments in the Dutch Republic and the regional politics in Mughal Bengal affected the situation in the VOC and its policies against corruption of its officials. Interdisciplinary Bridges for Indo-European Studies (IBIES) Erasmus MundusColonial and Global Histor