Theoretical Calculations of the Diffusion and Friction Coefficients for Neutral Atoms that Moving in a Laser Field

Haider Kamil Hanoon

doi:10.31257/2018/jkp/2019/110208

Abstract

This research aimed to study the friction and diffusion coefficients of neutral atoms that moving and interact with a laser field .The Mathcad 14 program used to calculate the results. The theoretical model was solved and shown the effect of different optical parameters on the diffusion and friction of neutral atoms .The different values of ellipticity (Ɛ) were used to find the friction and diffusion coefficients ,for each value of ellipticity we found that the relationship between the natural width of excited level( γ) and the difference(δ) between the frequency of laser field(ω) and the atomic resonance (ω0 ) has strong effect on the friction coefficient of atoms .The effect of Rabi frequency (Ω ) on the diffusion coefficient has been investigated .In this research the results showed that each of the parameters δ and Ω has effect on the diffusion of atom and the Rabi frequency has more influence. The dependence of the friction and diffusion coefficients on the natural width of the excited level was studied. The measuring of the friction and diffusion coefficients of atom very important to control the movement and then localize it, this have many applications in physics fields.

Highlights

Catch atoms or ions in a trap and using laser for cooling have a great developed in the field of atomic physics, and scientific projects in this field obtained many of Nobel prizes through the past 20 years [1,2,3]
And figure3b we can see there is a slight change in the diffusion coefficient D when δ increased by 10 times
Rabi frequency affect strongly on the diffusion coefficient of atom .The increasing of value of Rabi frequency leads to increase in the diffusion coefficient and the velocity of atom can be increase

Summary

Introduction

Catch atoms or ions in a trap and using laser for cooling have a great developed in the field of atomic physics, and scientific projects in this field obtained many of Nobel prizes through the past 20 years [1,2,3]. Einstein showed that a quantum of light – a photon with energy հν has an impulse p = հν/c=h/λ where h is Planck's constant, c ,v, λ is the speed, frequency and wavelength of light [17]. In this case the basis of the mechanism of light pressure is the exchange of momentum in the processes of absorption and emission of photons. The resonance cross section of photon scattering on an atom exceeds the Thomson cross section on an electron by 15 - 17 orders of magnitude. It can be said that a new intensively developing field of science has arisen connected with the mechanical action of resonant radiation on atoms

Objectives

Results

Conclusion