UV Completion
Encyclopedia
In theoretical physics
, ultraviolet completion, or UV completion, of a quantum field theory
is the passing from a lower energy quantum field theory to a more general quantum field theory above a threshold value known as the cutoff. In particular, the more general high energy theory must be well-defined at arbitrarily high energies, the so-called ultraviolet
(UV) regime.
The ultraviolet theory must be renormalizable; it can have no Landau pole
s; and most typically, it enjoys asymptotic freedom
in the case that it is a quantum field theory (or at least has a nontrivial fixed point
). However, it may also be a background of string theory
whose ultraviolet behavior is at least as good as that of renormalizable quantum field theories. Besides these two known examples (QFT and string theory), it could be a completely different theory than string theory that behaves well at very high energies.
Theoretical physics
Theoretical physics is a branch of physics which employs mathematical models and abstractions of physics to rationalize, explain and predict natural phenomena...
, ultraviolet completion, or UV completion, of a quantum field theory
Quantum field theory
Quantum field theory provides a theoretical framework for constructing quantum mechanical models of systems classically parametrized by an infinite number of dynamical degrees of freedom, that is, fields and many-body systems. It is the natural and quantitative language of particle physics and...
is the passing from a lower energy quantum field theory to a more general quantum field theory above a threshold value known as the cutoff. In particular, the more general high energy theory must be well-defined at arbitrarily high energies, the so-called ultraviolet
Ultraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...
(UV) regime.
The ultraviolet theory must be renormalizable; it can have no Landau pole
Landau pole
In physics, the Landau pole is the momentum scale at which the coupling constant of a quantum field theory becomes infinite...
s; and most typically, it enjoys asymptotic freedom
Asymptotic freedom
In physics, asymptotic freedom is a property of some gauge theories that causes interactions between particles to become arbitrarily weak at energy scales that become arbitrarily large, or, equivalently, at length scales that become arbitrarily small .Asymptotic freedom is a feature of quantum...
in the case that it is a quantum field theory (or at least has a nontrivial fixed point
UV fixed point
In a quantum field theory, one may calculate an effectiveor running coupling constant that defines thecoupling of the theory measured at a given momentum scale.One example of such a coupling constantis the electric charge...
). However, it may also be a background of string theory
String theory
String theory is an active research framework in particle physics that attempts to reconcile quantum mechanics and general relativity. It is a contender for a theory of everything , a manner of describing the known fundamental forces and matter in a mathematically complete system...
whose ultraviolet behavior is at least as good as that of renormalizable quantum field theories. Besides these two known examples (QFT and string theory), it could be a completely different theory than string theory that behaves well at very high energies.
See also
- Fermi's interactionFermi's interactionIn particle physics, Fermi's interaction also known as Fermi coupling, is an old explanation of the weak force, proposed by Enrico Fermi, in which four fermions directly interact with one another at one vertex...
- Quantum mechanicsQuantum mechanicsQuantum mechanics, also known as quantum physics or quantum theory, is a branch of physics providing a mathematical description of much of the dual particle-like and wave-like behavior and interactions of energy and matter. It departs from classical mechanics primarily at the atomic and subatomic...
- String theoryString theoryString theory is an active research framework in particle physics that attempts to reconcile quantum mechanics and general relativity. It is a contender for a theory of everything , a manner of describing the known fundamental forces and matter in a mathematically complete system...