Answer the following about ways to simplify notation in quantum field theory, for 10 points each.
[10e] These diagrams, which represent particle interactions, are used to compactly express the expansion of S-matrix elements.
ANSWER: Feynman (“FINE-mun”) diagrams [or Stueckelberg diagrams]
[10m] Slash notation is used to express the contraction of a covariant quantity with these four matrices, which are used to form the spinor (“SPIN-or”) representation of the Clifford algebra.
ANSWER: gamma matrices [or Dirac matrices]
[10h] Freeman Dyson introduced this operation often used in the interaction picture. It precedes an exponential term in Dyson’s formula.
ANSWER: time-ordering operation [accept time-ordered product; prompt on path-ordering or path-ordered or T; reject “time evolution (operator)”]
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