Search results
Results from the WOW.Com Content Network
A delta ray is a secondary electron with enough energy to escape a significant distance away from the primary radiation beam and produce further ionization. [1]: 25 The term is sometimes used to describe any recoil particle caused by secondary ionization. The term was coined by J. J. Thomson.
In quantum mechanics, the particle in a one-dimensional lattice is a problem that occurs in the model of a periodic crystal lattice.The potential is caused by ions in the periodic structure of the crystal creating an electromagnetic field so electrons are subject to a regular potential inside the lattice.
The Thomas–Fermi (TF) model, [1] [2] named after Llewellyn Thomas and Enrico Fermi, is a quantum mechanical theory for the electronic structure of many-body systems developed semiclassically shortly after the introduction of the Schrödinger equation. [3]
Dynamical mean-field theory, a non-perturbative treatment of local interactions between electrons, bridges the gap between the nearly free electron gas limit and the atomic limit of condensed-matter physics. [1] DMFT consists in mapping a many-body lattice problem to a many-body local problem, called an impurity model. [2]
In particle physics, the Dirac equation is a relativistic wave equation derived by British physicist Paul Dirac in 1928. In its free form, or including electromagnetic interactions, it describes all spin-1/2 massive particles, called "Dirac particles", such as electrons and quarks for which parity is a symmetry.
The delta potential is the potential = (), where δ(x) is the Dirac delta function. It is called a delta potential well if λ is negative, and a delta potential barrier if λ is positive. The delta has been defined to occur at the origin for simplicity; a shift in the delta function's argument does not change any of the following results.
Let ^,, denote a translation operator that shifts every wave function by the amount n 1 a 1 + n 2 a 2 + n 3 a 3 (as above, n j are integers). The following fact is helpful for the proof of Bloch's theorem:
This article describes the mathematics of the Standard Model of particle physics, a gauge quantum field theory containing the internal symmetries of the unitary product group SU(3) × SU(2) × U(1). The theory is commonly viewed as describing the fundamental set of particles – the leptons , quarks , gauge bosons and the Higgs boson .