Sotnikov A. Theory of ultraslow electromagnetic waves with low intensity in a Bose-Einstein condensate of a gas of alkali-metal atoms

The thesis is devoted to the construction of the microscopic theory that describes slowing of electromagnetic pulses in dilute gases of alkali-metal atoms with Bose-Einstein condensates. Green-functions formalism is generalized on the case of the response of a low-temperature hydrogenlike plasma to the perturbation by an external electromagnetic field. The dependence of the transition temperature to the state with a Bose-Einstein condensate on the parameters of the energy spectrum of hydrogenlike atoms is found. The conditions for slowing of optical and microwave signals in a Bose condensate of alkali-metal atoms are defined. The dependence of propagation parameters of an electromagnetic pulse in a condensate on the intensity of an external static homogeneous magnetic field is investigated. The influence of temperature effects on the optical properties of dilute gases in the condensed state is studied.