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Esaki, Giaever and Josephson shared the 1973 Nobel Prize in Physics for their works on quantum tunneling in solids. [18] [7] In 1981, Gerd Binnig and Heinrich Rohrer developed a new type of microscope, called scanning tunneling microscope, which is based on tunnelling and is used for imaging surfaces at the atomic level. Binnig and Rohrer were ...
The Born approximation has also been used to calculate conductivity in bilayer graphene [5] and to approximate the propagation of long-wavelength waves in elastic media. [ 6 ] The same ideas have also been applied to studying the movements of seismic waves through the Earth.
In relativistic quantum mechanics, the Klein paradox (also known as Klein tunneling) is a quantum phenomenon related to particles encountering high-energy potential barriers. It is named after physicist Oskar Klein who discovered in 1929. [ 1 ]
The operation of a scanning tunneling microscope (STM) relies on this tunneling effect. In that case, the barrier is due to the gap between the tip of the STM and the underlying object. Since the tunnel current depends exponentially on the barrier width, this device is extremely sensitive to height variations on the examined sample.
A finite ray or real ray is a ray that is traced without making the paraxial approximation. [12] [13] A parabasal ray is a ray that propagates close to some defined "base ray" rather than the optical axis. [14] This is more appropriate than the paraxial model in systems that lack symmetry about the optical axis.
This is particularly useful in laser physics, where one is interested in the populations of different atomic states in a gas when a time-dependent electric field is applied. These probabilities are also useful for calculating the "quantum broadening" of spectral lines (see line broadening) and particle decay in particle physics and nuclear physics.
In mathematical physics, the WKB approximation or WKB method is a method for finding approximate solutions to linear differential equations with spatially varying coefficients. It is typically used for a semiclassical calculation in quantum mechanics in which the wavefunction is recast as an exponential function, semiclassically expanded, and ...
Ray tracing of a beam of light passing through a medium with changing refractive index.The ray is advanced by a small amount, and then the direction is re-calculated. Ray tracing works by assuming that the particle or wave can be modeled as a large number of very narrow beams (), and that there exists some distance, possibly very small, over which such a ray is locally straight.