• S Sen

Articles written in Pramana – Journal of Physics

• Polarization and dichroism in atomic Auger spectroscopy following absorption of circularly polarized light

Spin resolved Auger current is shown to be different for the absorption of left and right circularly polarized light. This current is produced in non-radiative spontaneous decay of photoexcited atoms or of excited atomic photoions. Circular dichroism in such polarized Auger electrons exists even in the absence of spin-orbit interaction. Physical and geometrical conditions, necessary for the occurrence of dichroic effects in atomic Auger spectroscopy, have been obtained. Calculations for Ba and Xe show that the effect is substantially large and can be readily observed.

• Einstein pseudotensor and total energy of the universe

The total energy of the universe has been calculated assuming that it is the sum of the contributions from the matter part and gravitational part. The calculations involve the use of Einstein pseudotensor. Calculations have been carried out in some specific examples of spacetime geometries. In some cases the total energy is indeed zero confirming previous results but in other cases the total energy is nonzero. So Rosen’s idea that the pseudotensorial calculations will lead to the result that the total energy of the universe is zero, is very much model dependent.

• On the absence of scalar hair for charged rotating black holes in non-minimally coupled theories

In this work we check the validity of the no scalar hair theorem in charged axisymmetric stationary black holes for a wide class of scalar tensor theories.

• Working group report: Flavor physics and model building

This is the report of flavor physics and model building working group at WHEPP-9. While activites in flavor physics have been mainly focused on B-physics, those in model building have been primarily devoted to neutrino physics. We present summary of working group discussions carried out during the workshop in the above fields, and also briefly review the progress made in some projects subsequently.

• Bipartite entanglement in Auger ionisation of N${_2}$

Quantum entanglement and its paradoxical properties are of paramount importance in quantum information theory. In recent years, there has been an increasing interest in the studies of high-dimensional quantum states and their impact on quantum communication as it can encode and process more data. Photonic entanglement is usually an evanescent property as it is destroyed easily by its interaction with an external environment. Electronic qubits are stable and can store information for a long time. However, qudit systems are more efficient, stable and allow noise robustness than qubit system. In this article, we investigate bipartite entanglement between doubly ionised molecular qudit and electronic qubit in the Auger emission process for N${_2}$ molecule following the absorption of a single photon without observing spin-orbit interaction (SOI). In the absence of SOI, Russell–Saunders coupling (L-S coupling) is applicable. The entanglement properties are estimated on the basis of negativity of partial transpose of the density matrix for Auger ionisation. We find that the entanglement depends on the spins of the singly ionised excited states and doubly ionised states of the molecules as well as on the directions of spin quantisation and of ejection of Auger electrons. A significant effect on the variation of negativity due to the linear dichroism (LD) has also been observed.

• # Pramana – Journal of Physics

Volume 96, 2022
All articles
Continuous Article Publishing mode

• # Editorial Note on Continuous Article Publication

Posted on July 25, 2019