Conservation of the stress tensor in interacting quantum field theory in curved spacetimes

Apr, 2004
87 pages
Published in:
  • Rev.Math.Phys. 17 (2005) 227-312
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Abstract: (arXiv)
We propose additional conditions (beyond those considered in our previous papers) that should be imposed on Wick products and time-ordered products of a free quantum scalar field in curved spacetime. These conditions arise from a simple ``Principle of Perturbative Agreement'': For interaction Lagrangians L1L_1 that are such that the interacting field theory can be constructed exactly--as occurs when L1L_1 is a ``pure divergence'' or when L1L_1 is at most quadratic in the field and contains no more than two derivatives--then time-ordered products must be defined so that the perturbative solution for interacting fields obtained from the Bogoliubov formula agrees with the exact solution. The conditions derived from this principle include a version of the Leibniz rule (or ``action Ward identity'') and a condition on time-ordered products that contain a factor of the free field ϕ\phi or the free stress-energy tensor TabT_{ab}. The main results of our paper are (1) a proof that in spacetime dimensions greater than 2, our new conditions can be consistently imposed in addition to our previously considered conditions and (2) a proof that, if they are imposed, then for {\em any} polynomial interaction Lagrangian L1L_1 (with no restriction on the number of derivatives appearing in L1L_1), the stress-energy tensor Θab\Theta_{ab} of the interacting theory will be conserved. Our work thereby establishes (in the context of perturbation theory) the conservation of stress-energy for an arbitrary interacting scalar field in curved spacetimes of dimension greater than 2. Our approach requires us to view time-ordered products as maps taking classical field expressions into the quantum field algebra rather than as maps taking Wick polynomials of the quantum field into the quantum field algebra.
  • Quantum field theory on curved space
  • renormalization theory
  • stress tensor
  • perturbation theory
  • field theory: scalar
  • space-time
  • tensor: energy-momentum
  • axiomatic field theory
  • anomaly
  • field theory: interaction