arXiv subjects

V. A. Poghosyan

Publications and source records attributed to V. A. Poghosyan.

2 recordsLinked to original sources

arXiv2005

Package for Calculations and Simplifications of Expressions with Dirac Matrixes (MatrixExp)

This paper describes a package for calculations of expressions with Dirac matrixes. Advantages to existing similar packages are described. MatrixExp package is intended for simplification of complex expressions involving $γ$-matrixes, providing such tools as automatic Feynman parameterization, integration in $d$-dimensional space, sorting and grouping of results in a given order. Also, in comparison with existing similar package Tracer, presented package MatrixExp has more enhanced input possibility. User-available functions of MatrixExp package are described in detail. Also an example of calculation of Feynman diagram for process $b\to sγg$ with application of functions of MatrixExp package is presented.

hep-ph↗

arXiv2000

Optical Transition and Momentum Transfer in Atomic Wave Packets

It is shown that the population Rabi-floppings in a lossless two-level atom, interacting with a monochromatic electromagnetic field, in general are convergent in time. The well-known continuous floppings take place because the restricted choosing of initial conditions, that is when the atom initially is chosen on ground or excited level before the interaction, simultaneously having a definite value of momentum there. The convergence of Rabi-floppings in atomic wave-packet-states is a direct consequence of Doppler effect on optical transition rates (Rabi-frequencies): it gradually leads to ''irregular'' chaotic-type distributions of momentum in ground and excited energy levels, smearing the amplitudes of Rabi-floppings. Conjointly with Rabi-floppings, the coherent accumulation of momentum on each internal energy level monotonically diminishes too.

quant-ph↗