Semiclassical Approximation for Gravity and the Issue of Back Reaction

  title={Semiclassical Approximation for Gravity and the Issue of Back Reaction},
  author={T. Padmanabhan},
  journal={Classical and Quantum Gravity},
Semiclassical approximations, which are useful in the study of a quantum system interacting with a classical system, are studied and compared. A toy quantum mechanical model with two degrees of freedom (which mimics the features of gravity interacting with quantum fields) is used for illustration. In particular, the author considers the Born-Oppenheimer approximation (BOA) (corresponding to G to 0 at fixed h(cross)), the effective action approach (h(cross) to 0 at fixed G) and their… Expand
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