The focusing of the vacuum modes of a quantized field by a parabolic mirror is investigated. We use a geometric optics approximation to calculate the energy density and mean squared field averages for scalar and electromagnetic fields near the focus. We find that these quantities grow as an inverse power of the distance to the focus. There is an attractive Casimir-Polder force on an atom which ...

We observed quantum reflection of ultracold atoms from the attractive potential of a solid surface. Extremely dilute Bose-Einstein condensates of 23Na, with peak density 10(11)-10(12) atoms/cm(3), confined in a weak gravitomagnetic trap were normally incident on a silicon surface. Reflection probabilities of up to 20% were observed for incident velocities of 1-8 mm/s. The velocity dependence ag...

We explore the feasibility of probing atom-wall interaction with atomic clocks based on atoms trapped in engineered optical lattices. Optical lattice is normal to the wall. By monitoring the wall-induced clock shift at individual wells of the lattice, one would measure the dependence of the atom-wall interaction on the atom-wall separation. We find that the induced clock shifts are large and ob...

We demonstrate that a very recently obtained formula for the force on a slab in a material planar cavity based on the calculation of the vacuum Lorentz force [C. Raabe and D.-G. Welsch, Phys. Rev. A, 71, 013814 (2005)] describes a (medium) screened Casimir force and, in addition to it, a medium-assisted force. The latter force also describes the force on the cavity medium. For dilute media, it ...

In this paper we introduce a shadowing model for the volume scattering kernel component by land targets, such as vegetation, sand and soil. . The proposed BRDF model for heterogeneous land surfaces consists of three kernels, namely, an isotropic, a geometric and a volume scattering components and the new BRDF models with the shadowing volume kernel has been tested against the POLDER-1 BRDF data...

This paper addresses the design of the machinery of collective bargaining from the perspective of microeconomic and macroeconomic flexibility. In the former context, somewhat greater attention is given over to enterprise flexibility than external adjustment. In the latter context, close attention is also paid to changes in collective bargaining along the dimensions of bargaining coverage, struc...