The Källén function, also known as triangle function, is a polynomial function in three variables, which appears in geometry and particle physics. In the...

\end{aligned}}} Källén function, also known as triangle function Tent map Triangular distribution Triangle wave, a piecewise linear periodic function Trigonometric...

theory of functions of several complex variables, and collaborated on the Pauli–Källén equation. The Källén function, as well as the Källén–Yang–Feldman...

Lambda function (computer programming), or lambda abstraction AWS Lambda, a form of serverless computing Källén function, λ(x,y,z) or triangle function, a...

The Källén–Lehmann spectral representation, or simply Lehmann representation, gives a general expression for the (time ordered) two-point function of an...

myelencephalon). The spinal cord, which directly interacts with somatic functions below the head, can be considered a caudal extension of the myelencephalon...

the laboratory. If Källén–Lehmann spectral representation holds, at this stage we exclude gauge theories, the spectral density function can take a very simple...

In theoretical physics, specifically quantum field theory, a beta function, β(g), encodes the dependence of a coupling parameter, g, on the energy scale...

In quantum field theory, correlation functions, often referred to as correlators or Green's functions, are vacuum expectation values of time-ordered products...

In quantum mechanics and quantum field theory, the propagator is a function that specifies the probability amplitude for a particle to travel from one...

In quantum field theory, partition functions are generating functionals for correlation functions, making them key objects of study in the path integral...

around this, the Wightman axioms introduce the idea of smearing over a test function to tame the UV divergences, which arise even in a free field theory. Because...

as canonical quantization, in which the fields (typically as the wave functions of matter) are thought of as field operators, in a manner similar to how...

acts as a generating functional for one-particle irreducible correlation functions. The potential component of the effective action is called the effective...

two-point correlation function, two-point Green's function or two-point function for short.: 82  The free two-point function, also known as the Feynman...

itself (which is really a distribution, not a function) for the PDEs smeared over both test functions. This has the form of a CCR/CAR algebra. CCR/CAR...

products of pairs of these operators. This allows for the use of Green's function methods, and consequently the use of Feynman diagrams in the field under...

n-point correlation functions under variation of the energy scale at which the theory is defined and involves the beta function of the theory and the...

\phi (x)=B(x)+\eta (x)} . After this is done, the Green's functions are evaluated as a function of the background. This approach has the advantage that...

supercomputer. After Wick rotation, the path integral for the partition function of QCD takes the form Z = ∫ D U e − S [ U ] = ∫ ∏ x , μ d U μ ( x ) e −...

Casimir effect. This concept is important for working with correlation functions in quantum field theory. In the context of spontaneous symmetry breaking...

elements (the scattering amplitudes) from the time-ordered correlation functions of a quantum field theory. It is a step of the path that starts from the...

scalar function ψ used to change the gauge is called a gauge function.[citation needed] The existence of arbitrary numbers of gauge functions ψ(r, t)...

ISBN 0-12-617650-7. Kallen, Horace. 18–25 February 1915. "Democracy Versus the Melting Pot." The Nation 100(2590):190–94, 217–20. Kallen, Horace. 1924. Culture...

|\psi \rangle } is no longer a spatial wave function in the traditional sense of a complex-valued function that is defined on a 3-dimensional space-like...

extend the single-particle state function ψ ( r ) {\displaystyle \psi (\mathbf {r} )} to the N-particle state function ψ ( r 1 , r 2 , … , r N ) {\displaystyle...

a perturbative contribution to the transition amplitude or correlation function of a quantum mechanical or statistical field theory. Within the canonical...

}-\partial ^{\mu }f\ } where   f   {\displaystyle \ f\ } is an arbitrary function. Electromagnetic field Photon Quantum electrodynamics Quantum gravity Vector...

Higgs 't Hooft Iliopoulos Ivanenko Jackiw Jaffe Jona-Lasinio Jordan Jost Källén Kendall Kinoshita Kim Klebanov Kontsevich Kreimer Kuraev Landau Lee Lee...

In this case, the non-zero beta function tells us that the classical scale-invariance is anomalous. If a beta function is positive, the corresponding coupling...