Talk:Quantum field theory in curved spacetime

This page still needs major revision. The last section should be added as the opening part. The first section should be moved to a section as justification from standard model. The methods should be added in detail. The prediction and shortcomings of the theory must be written at the end of the article.

Particles Depend on Observer

This is said a lot, and it is misleading. The definition of "particle" here is the occupation number for a global field mode, an asymptotic definition. There is a second definition of particle which is local, where the particle is what you get when you apply a local field operator to the vacuum.

Then the excitations of the quantum field theory are represented as a sum over these local particle paths. The local particles are not different in different frames. The new particles in Unruh's and Hawking's calculation can, in the local particle picture, be traced back to the horizon, and they get to the detector by meandering around in the usual way.

The source of the confusion is the fact that the local-particle interpretation was confined to Feynman and a few others until the seventies. Everybody else followed Wigner and defined a particle as a global excitation which serves as an in or out state. This changed when quarks became particles, which was a catalyst for a linguistic transformation that caused people to redefine particles as local constructions in Feynman diagrams or in path integrals which follow particle trajectories, not as asymptotic excitations of global field modes.

I tried to make the distinction clear.Likebox (talk) 23:07, 8 January 2008 (UTC)

Experimental evidence

Has Quantum field theory in curved spacetime been confirmed by experimental evidence ? and which experiment? 222.252.111.226 (talk) 06:43, 22 November 2010 (UTC)