Massless particles, electromagnetism, and Rieffel induction

Jun, 1994
49 pages
Published in:
  • Rev.Math.Phys. 7 (1995) 923-958
e-Print:
Report number:
  • DESY-94-109

Citations per year

199419972000200320061203
Abstract: (arXiv)
The connection between space-time covariant representations (obtained by inducing from the Lorentz group) and irreducible unitary representations (induced from Wigner's little group) of the Poincar\'{e} group is re-examined in the massless case. In the situation relevant to physics, it is found that these are related by Marsden-Weinstein reduction with respect to a gauge group. An analogous phenomenon is observed for classical massless relativistic particles. This symplectic reduction procedure can be (`second') quantized using a generalization of the Rieffel induction technique in operator algebra theory, which is carried through in detail for electro- magnetism. Starting from the so-called Fermi representation of the field algebra generated by the free abelian gauge field, we construct a new (`rigged') sesquilinear form on the representation space, which is positive semi-definite, and given in terms of a Gaussian weak distribution (promeasure) on the gauge group (taken to be a Hilbert Lie group). This eventually constructs the algebra of observables of quantum electro- magnetism (directly in its vacuum representation) as a representation of the so-called algebra of weak observables induced by the trivial representation of the gauge group.
Note:
  • LaTeX, 52 pages
  • gauge field theory: U(1)
  • axiomatic field theory
  • Hamiltonian formalism
  • phase space: Hilbert space
  • operator: algebra
  • algebra: representation
  • mathematical methods