The laws of reflection and refraction are typically derived using a dispersion relation that assumes that the angular frequency stays the same across a vacuum–dielectric interface and that the angular wave number increases. At the single photon level, this means that the total energy of the photon is conserved but the linear momentum is not. Here I derive the laws of reflection and refraction f...

The conservation of energy, linear momentum, and angular momentum of the electromagnetic field in linear dielectric media with arbitrary dispersion and absorption is studied in the framework of an auxiliary field approach in which the electric and magnetic fields are complemented by a material field. This material field depends on a continuous variable omega, and describes harmonic motions of t...

The present work involves numerical simulation of a steady, incompressible forcedconvection fluid flow through a matrix of porous media between two parallel plates at constanttemperature. A Darcy model for the momentum equation was employed. The mathematical model forenergy transport was based on single phase equation model which assumes local thermal equilibriumbetween fluid and solid phases. ...

For the upgrade of the SIS-18 synchrotron it is of importance that the initial momentum spread of the injected coasting beam does not exceed the limit set by the rf bucket area. The lower limit is determined by microwave instabilities which cause a sudden increase of the momentum spread below a threshold momentum spread. For a coasting Ar beam in the SIS-18 the measured momentum spread as a fun...

We explore a possible connection between two aspects of Loop Quantum Gravity which have been extensively studied in the recent literature: the black-hole area-entropy law and the energymomentum dispersion relation. We observe that the original Bekenstein argument for the areaentropy law implicitly requires information on the energy-momentum dispersion relation. Recent results show that in first...

We present new constraints for the transportation behaviour of low-momentum electronic excitations in condensed matter systems, and demonstrate that these have both a fundamental physical interpretation and a significant impact on the description of low-energy inelastic electron scattering. The dispersion behaviour and characteristic lifetime properties of plasmon and single-electron excitation...

An electromagnetic gyrokinetic formulation is utilized to calculate the turbulent radial flux of parallel momentum for a strongly magnetized plasma in the large aspect ratio limit. For low-! plasmas, excluding regions of steep density gradients, the level of momentum transport induced by microturbulence is found to be well described within the electrostatic approximation. However, near regions ...

Sodium, which has long been regarded as one of the simplest metals, displays a great deal of structural, optical, and electronic complexities under compression. We compressed pure Na in the body-centered cubic structure to 52 GPa and in the face-centered cubic structure from 64 to 97 GPa, and studied the plasmon excitations of both structures using the momentum-dependent inelastic X-ray scatter...

Electron momentum spectroscopy (EMS) is a scattering experiment that determines the spectral function of a sample, i.e. the density of electrons as a function of binding energy and momentum. Here, it is used to study the spectral function of silicon single crystals in the extended zone scheme. Two symmetry directions and four intermediate directions are measured. The relation between the band i...