We define and discuss measures of coherence for matter waves. These characterize the interference pattern arising from the overlap of one point of a matter wave with another. We identify two coherence quantities, one related to the distance between the interfering parts of a matter wave, and one describing the influence of the position within the wave. We show that our coherence properties are ...

Amplitude modulation and packet formation of Langmuir waves are commonly observed during a nonlinear interaction between electron beams and plasmas. In this paper, we briefly review the history of Langmuir wave packets as developed by recent spacecraft observations and computer simulations. New one-dimensional electrostatic Vlasov simulations are performed to study their formation processes. It...

Two parallel, relativistic electron streams with different velocities support unstable, exponentially growing space-charge waves, and efficient electron bunching may be achieved in the submillimeter wavelength range. Injection of the prebunched streams into a static, periodic (wiggler) magnetic field enhances the intensity of the parametrically excited, back-scattered electromagnetic wave. Calc...

We show theoretically that the shape of a beam of matter waves cold atoms emerging from one subwavelength aperture pierced in a film can be collimated within a few degrees. By means of an external laser field, a potential well for the atoms in the direction perpendicular to the surface is created. In this way, a running surface matter wave can be excited when atoms diffract from the aperture. I...

A corrugated magnetic reflector is realized by adding a bias field to a static magnetic mirror. This permits real-time manipulation of a cold-atom cloud on time scales down to 100 ms. We show that rotation of the bias field generates a traveling corrugation of adjustable depth and velocity. Momentum is transferred from the traveling wave to the atoms, resulting in a displacement of the cloud th...

The two-dimensional wave-breaking of relativistic plasma waves driven by a ultrashort high-power lasers, is described within a framework of cold 2-D fluid theory. It is shown that the transverse nonlinearity of the plasma wave results in temporally increasing transverse plasma oscillation in the wake of the laser pulse, inevitably inducing wave-breaking below the 1-D threshold. A condition for ...

Two-dimensional (p(x)+ip(y)) superfluids or superconductors offer a playground for studying intriguing physics such as quantum teleportation, non-Abelian statistics, and topological quantum computation. Creating such a superfluid in cold fermionic atom optical traps using p-wave Feshbach resonance is turning out to be challenging. Here we propose a method to create a p(x)+ip(y) superfluid direc...

To facilitate the construction of the high-power magnetron, the entire output section, including the quarter wave transformer and window, has been redesigned. The new design is based on standard S band waveguide. The quarter wave transformer was changed to increase the external loading of the tube. Cold test measurements on a tube with the redesigned output section give an external Q of 230. Wo...

Chiral p-wave superfluids are fascinating topological quantum states of matter that have been found in the liquid (3)He-A phase and arguably in the electronic Sr2RuO4 superconductor. They are fundamentally related to the fractional 5/2 quantum Hall state, which supports fractional exotic excitations. Past studies show that they require spin-triplet pairing of fermions by p-wave interaction. Her...

[1] A well-mixed water column is observed over a 20 m ridge in the central Bohai Sea, surrounded by stratified water of much colder temperatures. We use a three-dimensional model to investigate its formation mechanisms. The results show that both tidal and surface wave mixing are important for homogenizing the water column, the former reaching 10 m above the bottom and the latter penetrating 10...