Advanced action in classical electrodynamics

The time evolution of a charged point particle is governed by a second-order integro-differential equation that exhibits advanced effects, in which the particle responds to an external force before the force is applied. In this paper we give a simple physical argument that clarifies the origin and physical meaning of these advanced effects, and we compare ordinary electrodynamics with a toy model of electrodynamics in which advanced effects do not occur.Comment: 12 pages, 5 figure

Determination of the number of atoms trapped in an optical cavity

The number of atoms trapped within the mode of an optical cavity is determined in real time by monitoring the transmission of a weak probe beam. Continuous observation of atom number is accomplished in the strong coupling regime of cavity quantum electrodynamics and functions in concert with a cooling scheme for radial atomic motion. The probe transmission exhibits sudden steps from one plateau to the next in response to the time evolution of the intracavity atom number, from Ngreater than or equal to 3 to N=2-->1-->0 atoms, with some trapping events lasting over 1 s

Cavity QED "By The Numbers"

The number of atoms trapped within the mode of an optical cavity is determined in real time by monitoring the transmission of a weak probe beam. Continuous observation of atom number is accomplished in the strong coupling regime of cavity quantum electrodynamics and functions in concert with a cooling scheme for radial atomic motion. The probe transmission exhibits sudden steps from one plateau to the next in response to the time evolution of the intracavity atom number, from N >= 3 to N = 2 to 1 to 0, with some trapping events lasting over 1 second.Comment: 5 pages, 4 figure

Trapped atoms in cavity QED: coupling quantized light and matter

On the occasion of the hundredth anniversary of Albert Einstein's annus mirabilis, we reflect on the development and current state of research in cavity quantum electrodynamics in the optical domain. Cavity QED is a field which undeniably traces its origins to Einstein's seminal work on the statistical theory of light and the nature of its quantized interaction with matter. In this paper, we emphasize the development of techniques for the confinement of atoms strongly coupled to high-finesse resonators and the experiments which these techniques enable

Orthogonal conductivity of a toroidal plasma

The orthogonal conductivity of a toroidal plasma is calculated in the fluid regime. If the damping time for toroidally directed angular momentum is tau/sub N/, the orthogonal conductivity is shown to be sigma/sub perpendicular to/ = (rhoc$sup 2$/ B$sup 2$/sub p/)/tau/sub n/ for large tau/sub N/. Here rho is the mass density, c the speed of light and B/sub p/ the poloidal component of the magnetic field. For large tau/sub N/, the flow induced by the orthogonal electric field is almost purely toroidal and of magnitude. c (E/sub r/ -- E$sup 0$/sub r/)/B/sub p/ where E$sup 0$/sub r/ is the electric field required for ambipolar diffusion. (auth