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Tunneling is readily detectable with barriers of thickness about 1–3 nm or smaller for electrons, and about 0.1 nm or smaller for heavier particles such as protons or hydrogen atoms. [1] Some sources describe the mere penetration of a wave function into the barrier, without transmission on the other side, as a tunneling effect, such as in ...
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 ]
Therefore, the transition to the true vacuum must be stimulated by the creation of high-energy particles or through quantum-mechanical tunneling. In quantum field theory, a false vacuum [1] is a hypothetical vacuum state that is locally stable but does not occupy the most stable possible ground state. [2] In this condition it is called metastable.
In physics, tunnel ionization is a process in which electrons in an atom (or a molecule) tunnel through the potential barrier and escape from the atom (or molecule). In an intense electric field, the potential barrier of an atom (molecule) is distorted drastically. Therefore, as the length of the barrier that electrons have to pass decreases ...
Gamow discovered a theoretical explanation of alpha decay by quantum tunneling, invented the liquid drop model - the first mathematical model of the atomic nucleus, worked on radioactive decay, star formation, stellar nucleosynthesis, Big Bang nucleosynthesis (which he collectively called nucleocosmogenesis), predicted the existence of the ...
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.
An alpha particle with a speed of 1.5×10 7 m/s within a nuclear diameter of approximately 10 −14 m will collide with the barrier more than 10 21 times per second. However, if the probability of escape at each collision is very small, the half-life of the radioisotope will be very long, since it is the time required for the total probability ...
The principal ray or chief ray (sometimes known as the b ray) in an optical system is the meridional ray that starts at an edge of an object and passes through the center of the aperture stop. [ 5 ] [ 8 ] [ 7 ] The distance between the chief ray (or an extension of it for a virtual image) and the optical axis at an image location defines the ...