Atomic collisions mediated by photons

Author(s)

Yuri Alexandrovish Barbosa

• Document type: Doctoral Thesis
• Press: São Carlos.
• Institution: Universidade de São Paulo (USP). Instituto de Física de São Carlos (IFSC/BT)
• Defense date: 2004-02-17

Examining board members

Reginaldo de Jesus Napolitano; Esmerindo de Sousa Bernardes; Bernhard Joachim Mokross; Gilberto Aparecido Prataviera; José Antonio Roversi

• Advisor: Reginaldo de Jesus Napolitano

Abstract

We study atomic collisions mediated by photons. Due to the presence of remnant light, we consider atomic decay and excitation processes. In particular, the atomic decay is important to the study of magneto-optical traps, because this process is one of the factors limiting the time of atomic confinement in these devices. We present a new formulation to solve numerically the equations describing the populations and coherences involved in the collision process of a pair of two-level atoms. This is a numerically exact approach; hence we have been able to check the semi-classical results. We verify that the validity of this approximation is restricted to certain ranges of momentum and wave-packet width, both associated with the reduced particle. Based on current optical-lattice technology, we also present a thought experiment in which it is possible to prepare an initial state of the two colliding atoms in the presence of a probe laser beam. Another study concerns the verification of the existent of an effective potential which gives the correct asymptotic quantum collision output in a classical Liouvillian framework (AU)