Research Publications
Permanent URI for this communityhttp://localhost:4000/handle/11007/1
Browse
2 results
Search Results
Item Probes of vacuum structure of quantum fields in classical backgrounds(World Scientific Publishing Company, 2000-10-04) Sriramkumar, L.; Padmanabhan, T.We compare the different approaches presently available in literature to probe the vacuum structure of quantum fields in classical electromagnetic and gravitational back- grounds. We compare the results from the Bogolubov transformations and the effective Lagrangian approach with the response of monopole detectors (of the Unruh - DeWitt type) in noninertial frames in flat spacetime and in inertial frames in different types of classical electromagnetic backgrounds. We also carry out such a comparison in inertial and rotating frames when boundaries are present in flat spacetime. We find that the results from these different approaches do not, in general, agree with each other. We attempt to identify the origin of these differences and then go on to discuss its implications for classical gravitational backgrounds.Item Nontrivial classical backgrounds with vanishing quantum corrections(American Physical Society, 1996-11-15) Sriramkumar, L.; Mukund, R.; Padmanabhan, T.Vacuum polarization and particle production effects in classical electromagnetic and gravitational back-grounds can be studied by the effective Lagrangian method. Background field configurations for which the effective Lagrangian is zero are special in the sense that the lowest order quantum corrections vanish for such configurations. We propose here the conjecture that there will be neither particle production nor vacuum polarization in classical field configurations for which all the scalar invariants are zero. We verify this conjec-ture, by explicitly evaluating the effective Lagrangian, for nontrivial electromagnetic and gravitational back-grounds with vanishing scalar invariants. The implications of this result are discussed.