propagator
Sign in to saveIn quantum mechanics and quantum field theory, the propagator is a function that specifies the probability amplitude for a particle to travel from one place to another in a given period of time, or to travel with a certain energy and momentum. In Feynman diagrams, which serve to calculate the rate of collisions in quantum field theory, virtual particles contribute their propagator to the rate of the scattering event described by the respective diagram. Propagators may also be viewed as the inverse of the wave operator appropriate to the particle, and are, therefore, often called ''(causal) Gre
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Article
28 sectionsContents
- Non-relativistic propagators
- Examples
- Relativistic propagators
- Scalar propagator
- Position space
- Causal propagators
- Retarded propagator
- Advanced propagator
- Feynman propagator
- Dirac propagator
- Momentum space propagator
- Faster than light?
- Explanation using limits
- Propagators in Feynman diagrams
- Other theories
- Spin {{frac|1|2}}
- Spin 1
- Graviton propagator
- Related singular functions
- Solutions to the Klein–Gordon equation
- Pauli–Jordan function
- Positive and negative frequency parts (cut propagators)
- Auxiliary function
- Green's functions for the Klein–Gordon equation
- See also
- Notes
- References
- External links
In quantum mechanics and quantum field theory, the propagator is a function that specifies the probability amplitude for a particle to travel from one place to another in a given period of time, or to travel with a certain energy and momentum. In Feynman diagrams, which serve to calculate the rate of collisions in quantum field theory, virtual particles contribute their propagator to the rate of the scattering event described by the respective diagram. Propagators may also be viewed as the inverse of the wave operator appropriate to the particle, and are, therefore, often called ''(causal) Green's functions (called "causal''" to distinguish it from the elliptic Laplacian Green's function).
==Non-relativistic propagators== In non-relativistic quantum mechanics, the propagator gives the probability amplitude for a particle to travel from one spatial point (x') at one time (t') to another spatial point (x) at a later time (t).