Quantum field theory

three variables 𝑠, 𝑡, 𝑢 used to parametrize the kinematics of two particle scattering

In physics, the '''S-matrix or scattering matrix''' is a matrix that relates the initial state and the final state of a physical system undergoing a scattering process. It is used in quantum mechanics, scattering theory and quantum field theory (QFT).

quantum field theory whose correlation functions do not depend on the spacetime metric

massless boson that must be present in a quantum system with spontaneously broken symmetry

a quantum state that is an element of a Fock space with a well-defined number of particles (or quanta)

In physics, the Zitterbewegung (, ) is the theoretical prediction of a rapid oscillatory motion of elementary particles that obey relativistic wave equations. This prediction was first discussed by Gregory Breit in 1928. The word was first applied to the relativistic motion of free electrons by Erwin Schrödinger in 1930 in his analysis of wave packet solutions of the Dirac equation for relativistic electrons in free space. These exhibit interference between positive and negative energy states, which produces an apparent fluctuation (up to the speed of light) of the position of an electron aro

relativistic wave equation

interaction in particle physics

type of approximation to an underlying physical theory

theory of particle physics

process of converting a classical physical theory into one compatible with quantum mechanics

theorem that states that a particular situation is not physically possible

formal analytic continuation of the time coordinate that changes a Lorentzian metric signature to a Euclidean one

anticommutating number

2^{⌊n/2⌋}-dimensional complex representation of the spin group Spin(n)

scale

expectation value of a local operator at a vacuum of a quantum field theory, whose nonzero value may effect the Higgs mechanism

three-dimensional topological quantum field theory whose action is the Chern–Simons form

In quantum field theory, the energy that a particle has as a result of changes that it causes in its environment defines its self-energy \Sigma. The self-energy represents the contribution to the particle's energy, or effective mass, due to interactions between the particle and its environment. In electrostatics, the energy required to assemble the charge distribution takes the form of self-energy by bringing in the constituent charges from infinity, where the electric force goes to zero. In a condensed matter context, self-energy is used to describe interaction induced renormalization of quas

mathematical notation used in quantum field theory for contractions with the Dirac gamma matrices

procedure to render finite infinite integrals arising in perturbation theory

summability method in physics

theorem about the impossibility of spontaneous symmetry breaking in two-dimensional systems at finite temperature

physical model treating some aspects in terms of quantum mechanics and others by classical physics

field theory of scalar fields

configurations of a system that do or do not satisfy classical equations of motion

equation for two-body bound states

equations for correlation functions in QFT

matrix element computed by inserting a product of operators between two states in quantum field theory

deviations from local realism characteristic of quantum mechanics

procedure of putting a quantum field theory on fewer spatial dimensions than before

framework to describe phase transitions

manifestation of nothingness

class of quantum field theory models

theorem transforming derivatives into combinatorics problems applied in quantum field theory

properties underlying modern physics

physical quantities that take discrete values because of topological quantum physical effects

procedure of coping with redundant degrees of freedom in physical field theories

type of operator ordering in quantum field theory

expression for two-point correlation functions

perturbative expansion of the time evolution operator in the interaction picture

relativistic wave equation describing the propagation of a free spin 1½ particle

Physics theorem for symmetries of action

quantum field theory

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interpretation of quantum mechanics according to which retarded (forward in time) and advanced (backward in time) waves form a quantum interaction as a Wheeler–Feynman handshake

fields without physical meaning to introduce mathematical consistency

coulomb potential with vacuum polarization corrections

nonlinear generalization of electrodynamics with a maximum field strength

symmetry breaking in physics

formula stating that S-matrix elements are residues of on-shell poles of the Fourier transform of time-ordered correlation functions

type of quantum field

describing the interaction between a photon and an electron

a transformation that maps spin operators onto fermionic creation and annihilation operators

expansion of the product of two local operators inserted close to each other as an asymptotic series with local-operator coefficients

methods to calculate expectation values of physical observables of a quantum field theory at finite temperature

theorem that spacetime symmetries cannot mix with internal ones in a relativistic quantum field theory

classification of topological quantum field theories

possible outcome of renormalization in physics