Recent content by Giuseppe Lacagnina

  1. Giuseppe Lacagnina

    Graduate Lorentz transformations and vector fields

    Hi Everyone. There is an equation which I have known for a long time but quite never used really. Now I have doubts I really understand it. Consider the unitary operator implementing a Lorentz transformation. Many books show the following equation for vector fields: U(\Lambda)^{-1}A^\mu...
    • Giuseppe Lacagnina
    • Thread
    • Fields Lorentz Lorentz transformations Qft Representation theory Transformations Vector Vector fields
    • Replies: 1
    • Forum: Quantum Physics
  2. Giuseppe Lacagnina

    Graduate Can a Lagrangian in QFT be Renormalizable?

    As far as I know, a lagrangian term is not perturbatively renormalizable if it involves a coupling with negative mass dimension. Like it happens for gravity or the Fermi model of weak interactions, which works as an effective theory with an energy cutoff.
  3. Giuseppe Lacagnina

    Graduate Can a Lagrangian in QFT be Renormalizable?

    Possibly very silly question in QFT. Consider the Lagrangian for a scalar field theory. A term like g/φ^2 should be renormalizable on power counting arguments. The mass dimension of g should be 2 (D-1) where D is the number of space-time dimensions.Does this make sense?