Let us consider a single particle in an interferometer. If one of the two possible paths is blocked and the particle is detected, we know that the particle has followed the path which is not blocked. This would be an interference-free “which-path” information experiment. However, we no longer have an interferometer, since one path is blocked. An alternative is to interact with the particle, but...

The phase time in quantum tunneling can be disentangled into a dwell time plus a term arising due to the interference of the reflected and incident waves in front of the barrier. The interference term dominates at low energies and as E → 0, this term and hence the phase time becomes singular. With the s-wave motion in three dimensions being equivalent to that of a one-dimensional motion in the ...

Is light a wave or a particle? The Dutch physicist Christiann Huygens (1629-1695) advocated that light was a wave. Huygens principle is often used to describe how waves in general propagate. In 1704 Newton published the first edition of his book Optiks in which he championed the notion that light consisted of particles which we now call photons. Thomas Young performed a two slit interference ex...

We report generation of four-wave mixing enhanced by electromagnetically induced transparency and optical pumping in a ladder-type atomic system. When two pumping laser beams are used to form a conjugate small-angle static grating, both four-wave and six-wave mixing processes are shown to exist at the same time. Interference between these two nonlinear wave-mixing signals is experimentally demo...

Magnetization dynamics in nanomagnets has attracted broad interest since it was predicted that a dc current flowing through a thin magnetic layer can create spin-wave excitations. These excitations are due to spin momentum transfer, a transfer of spin angular momentum between conduction electrons and the background magnetization, that enables new types of information processing. Here we show ho...

The phenomenon of the polarization suppression of X-ray Umweg multiple waves in Renninger scans [Renninger (1937). Z. Kristallogr. 97, 107-121] of crystals, showing intensity decrease due to properly chosen wavelength and polarization of incident radiation, is observed. That is, one of the participating wave components in the multiple-wave interference is reduced considerably so that the intens...

As an important remote sensing technology, millimeter-wave radar is used for environmental in many fields due to its advantages of all-day, all-weather operation. With the increasing use radars, inter-radar interference becomes increasingly critical. Severe mutual degrades signal quality and affects performance post-processing, e.g., synthetic aperture (SAR) imaging target tracking. Aiming deal...

Propagation of energy along the sound channel axis cannot be formally described in terms of geometrical acoustics due to repeated cusped caustics along the axis. In neighborhoods of these cusped caustics, a very complicated interference pattern is observed. Neighborhoods of interference grow with range and overlap at long ranges. This results in the formation of a complex interference wave--the...