Passage Of Atoms Research Articles

Laser pumping and magneto-optical rotation of the light polarization plane in a cell with an antirelaxation coating of the walls: I. Statement and solution of the problem

A general solution of the Boltzmann kinetic equations for the atomic density matrix in a long cylindrical cell with an antirelaxation coating of the walls under conditions of laser pumping in a magnetic field is obtained. The theory involves only one relaxation parameter—the coefficient K refl of the diffusion reflection of polarized atoms from the cell walls. The solution consists of two terms. The first term is proportional to K refl and describes the contribution to the atomic polarization made by multiple passages of atoms through the pumping beam after their reflection from the walls with the antirelaxation coating. The second term does not depend on K refl and describes the polarization formed during a single passage of atoms through the pumping beam. This solution allows one to calculate the Stokes parameters for the pumping beam transmitted through the cell that are measured in experiments on magneto-optical rotation of the light polarization plane.

Adiabatic state preparation in a cavity

The paper discusses the single-mode Jaynes-Cummings model with time-dependent parameters. Solvable models for two-level systems are utilized to consider the changes in the photon distribution effected by the passage of atoms through the cavity. It is suggested that such systems may be used as filters to modify the photon distribution. The effect can be enhanced by repeatedly sending new atoms through the cavity. We show that such filters can cut out either small or large photon numbers. It is also shown that the method can be used to narrow down photon distributions and in this way achieve highly non-classical sub-Poissonian states. Some limitations and applications of the method are presented.

Adiabatic state preparation in a cavity

The paper discusses the single-mode Jaynes-Cummings model with time-dependent parameters. Solvable models for two-level systems are utilized to consider the changes in the photon distribution effected by the passage of atoms through the cavity. It is suggested that such systems may be used as filters to modify the photon distribution. The effect can be enhanced by repeatedly sending new atoms through the cavity. We show that such filters can cut out either small or large photon numbers. It is also shown that the method can be used to narrow down photon distributions and in this way achieve highly non-classical sub-Poissonian states. Some limitations and applications of the method are presented.

Tunneling and traversal of ultracold atoms through vacuum-induced potentials

We examine the passage of ultra-cold two-level atoms through the potential produced by the vacuum of the cavity field. The peak of the transmitted wave packet generally occurs at the instant given by the expression for phase time even if that instant is earlier than the instant at which incident wave packet's peak enters the cavity and thus the phase time can be considered as the appropriate measure of the time required for the atom to traverse the cavity. We show that the phase tunneling time for ultra-cold atoms could be both super - and sub - classical time and we show how this behaviour can be understood in terms of the momentum dependence of the phase of transmission amplitude. The passage of the atom through the cavity is unique as it involves a coherent addition of the transition amplitudes corresponding to both barrier and well. New features such as the splitting of the wave packet arise from the entanglement between the center of mass motion and the electronic as well as field states in the cavity.