History 181B - Class 40

History 181B: Modern Physics

Class 40 (4/30/03)
Renormalization

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Outline

Facing the infinities? Renormalized QED (continued)
   War work and postwar theory
       Schwinger and Tomonaga (recap)
       Feynman
           Disassembling the diagrams
           Reassembling them: Perturbation theory
           Thinking out of daily experience
           Los Alamos and modularity
    Assembling a full-fledged renormalized QED
    A conservative response to calls for radical change

Rethinking quantum field theory
Renormalization: QED and beyond
Renormalizability as a criterion for theories

New particles, new forces
    The data flood
    Strategies in the face of multiplicity
    The rise and fall (and rise again) of QFT

Names and terms

Primary	Secondary
quantum electrodynamics (QED) Sin-itiro Tomonaga (1906-1979), NP 1965 Julian Schwinger (1918-1994), NP 1965 Richard Feynman (1918-1988), NP 1965 propagator, vertex perturbation theory fine structure constant alpha = e² / h-bar c Freeman Dyson (1923 - ) S matrix 4 forces: EM, weak, strong, gravity	path-integral formulation coupling constant Fermi-field theory = 4-fermion interaction Geoffrey Chew (1924 - )

Assignment

Freeman J. Dyson, "Tomonaga, Schwinger, and Feynman Awarded Nobel Prize for Physics," Science 150 (1965): 588-589.

    What made Dyson consider QED so successful?
    How were theory and experiment related in this episode?
    Who were the radicals over which Dyson's conservatives triumphed?
    Extra: If the problems discussed here are so complicated and messy, and three different physicists tackled it in very different ways, how could people see that they were ultimately doing the same thing?