Photoelectric effect
... The Physics The cathode ray tube has a source of electrons (the cathode rays) which are accelerated using an electric potential difference and “steered” using coils. When the electrons collide with phosporus atoms on the screen photons in the visible region are produced. An x-ray tube works in the s ...
... The Physics The cathode ray tube has a source of electrons (the cathode rays) which are accelerated using an electric potential difference and “steered” using coils. When the electrons collide with phosporus atoms on the screen photons in the visible region are produced. An x-ray tube works in the s ...
6pp
... • Let us consider a particle, say an electron, moving through space. We describe the electron's motion in terms of its position and momentum. • Classically we can measure both quantities to infinite precision. • However in Quantum Mechanics we can never know both quantities absolutely precisely. • T ...
... • Let us consider a particle, say an electron, moving through space. We describe the electron's motion in terms of its position and momentum. • Classically we can measure both quantities to infinite precision. • However in Quantum Mechanics we can never know both quantities absolutely precisely. • T ...
Phys. Rev
... Avoided level crossing which becomes sharp in the infinite volume limit: second-order transition ...
... Avoided level crossing which becomes sharp in the infinite volume limit: second-order transition ...
Renormalization
In quantum field theory, the statistical mechanics of fields, and the theory of self-similar geometric structures, renormalization is any of a collection of techniques used to treat infinities arising in calculated quantities.Renormalization specifies relationships between parameters in the theory when the parameters describing large distance scales differ from the parameters describing small distances. Physically, the pileup of contributions from an infinity of scales involved in a problem may then result in infinities. When describing space and time as a continuum, certain statistical and quantum mechanical constructions are ill defined. To define them, this continuum limit, the removal of the ""construction scaffolding"" of lattices at various scales, has to be taken carefully, as detailed below.Renormalization was first developed in quantum electrodynamics (QED) to make sense of infinite integrals in perturbation theory. Initially viewed as a suspect provisional procedure even by some of its originators, renormalization eventually was embraced as an important and self-consistent actual mechanism of scale physics in several fields of physics and mathematics. Today, the point of view has shifted: on the basis of the breakthrough renormalization group insights of Kenneth Wilson, the focus is on variation of physical quantities across contiguous scales, while distant scales are related to each other through ""effective"" descriptions. All scales are linked in a broadly systematic way, and the actual physics pertinent to each is extracted with the suitable specific computational techniques appropriate for each.