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P. Rudra

Publications and source records attributed to P. Rudra.

4 recordsLinked to original sources
arXiv2022

Traversable wormhole in logarithmic $f(R)$ gravity by various shape and redshift functions

We study the traversable wormhole solutions for a logarithmic corrected $f(R)$ model by considering two different statements of shape $b(r)$ and redshift $Φ(r)$ functions. We calculate the parameters of the model including energy density $ρ$, tangential pressure $P_{t}$ and radial pressure $P_{r}$ for the corresponding forms of the functions. Then, we investigate different energy conditions such as null energy condition, weak energy condition, dominant energy condition and strong energy condition for our considered cases. Finally, we explain the satisfactory conditions of energy of the models by related plots.

gr-qc↗
arXiv2009

A Short History of Hindu Astronomy & Ephemeris

We have summarized here the astronomical knowledge of the ancient Hindu astronomers. This knowledge was accumulated from before 1500 B.C. up to around 1200 A.D. In Section \ref{equiv} we have correlated terms used by the Hindu astronomers and their equivalents in modern astronomy. In Section \ref{coord} we have defined the different astronomical coordinate systems and their transformation relations. In Sections \ref{seasons} and \ref{cycles} we have collected the main features of solar and lunar motions in terms of modern astronomical terminology. In Section \ref{stars} we have given the names of the stars mentioned by the Hindu astronomers and their modern names with the present astronomical coordinates. In Section \ref{hist} we have given a short survey of Indian history with emphasis to Hindu astronomy. In Sections \ref{vedas} and \ref{sid} we have given short descriptions of the main sources of Hindu astronomy. In Section \ref{astron} the important features of Hindu astronomy have been described. All through the article we have tried to present the content in tabular forms for ready and unambiguous perception.

physics.hist-ph↗
arXiv1999

Contact symmetry of time-dependent Schrödinger equation for a two-particle system: symmetry classification of two-body central potentials

Symmetry classification of two-body central potentials in a two-particle Schrödinger equation in terms of contact transformations of the equation has been investigated. Explicit calculation has shown that they are of the same four different classes as for the point transformations. Thus in this problem contact transformations are not essentially different from point transformations. We have also obtained the detailed algebraic structures of the corresponding Lie algebras and the functional bases of invariants for the transformation groups in all the four classes.

math-ph↗