propagator


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Propagator (field theory)

The probability amplitude for a particle to move or propagate to some new point of space and time when its amplitude at some point of origination is known. The propagator occurs as an important part of the probability in reactions and interactions in all branches of modern physics. Its properties are best described in the framework of quantum field theory for relativistic particles, where it is written in terms of energy and momentum. Concrete examples for electron-proton and proton-proton scattering are provided in the illustration. The amplitude for these processes contains the propagators for the exchanged proton and meson, which actually specify the dominant part of the probability of each process when the scattering occurs at small angles. In similar fashion, for any electromagnetic process, a propagator for each internal line of the Feynman diagram (each line not connected directly to the outside world) enters the probability amplitude. See Feynman diagram, Quantum electrodynamics, Quantum field theory, Quantum mechanics

Feynman diagrams for scattering processesenlarge picture
Feynman diagrams for scattering processes

propagator

[′präp·ə‚gād·ər]
(quantum mechanics)
The probability amplitude for a particle to move or propagate to some new point of space and time when its amplitude at some point of origination is known.
References in periodicals archive ?
The Garland Triple Top Electric Windowsill Propagator, (pounds 26 from 01384 278 256, garlandproducts.
If you want to grow tomatoes, cucumbers and courgettes which you are expecting to grow on in the greenhouse in summer, you can sow them early in heated propagators.
Garden centres, mail order and online retailers offer a wealth of heated propagators of different sizes and prices vary enormously, so do some research into exactly what conditions the seeds you want to sow need.
If the propagator is tall enough, the seedlings can be allowed to grow on in it, but at a lower temperature.
To learn more about Talarian, the PGM propagator or other Talarian multicast transport solutions visit the website at www.
Things such as staging, propagators, watering systems and automatic vent openers, plus blinds, heaters and insulation will also rack up costs.
Sow seeds indoors in early spring in pots or modules filled with seed compost and fine vermiculite and germinate in a propagator at 15C (59F).
Seeds should be sown indoors in late winter or early spring in a heated propagator in a bright position in individual 3 1/2 in pots of moist seed compost.
Despite money being a propagator of poverty and exploitation, your Acting Witan (or Mercian Assembly) has now fashioned a coin if you fully register yourself as a Mercian.
A temperature of 65-70F is good for germination so you should consider buying a heated propagator.
As a back-up, take some cuttings about four or five inches long and root them in a heated propagator or greenhouse, or again on the window sill.