Abstract:
QFT in curved spacetime is a semi classical approximation to any theory
of quantum gravity which as of date remains elusive to nd. Though the
foundations of this subject were rmly established as early as 1970, there is
still a lot of debate and discussion which has sometimes culminated in 'wars'
on topics such as information paradox, the violation of basic symmetries in
black holes, the nal stages of evaporation of a black hole and many others
even as of today.
We work in a paradigm where gravity is considered as a classical theory
and the matter elds are quantum in nature. Also we work at energy scales
much less than the Plank scale so that we are justi ed in neglecting the non
perturbative e ects of the quantum nature of gravity. As we shall see non
trivial e ects of gravitation occur in the quantum eld modes only then the
wavelength of the modes is of the order of characteristic length scales of the
background metric which implies we can verify the predicted results only at
large energies which were prevalent at early times just after the big bang.
As a consequence most of the results remain theoretical and experimental
checks are rare.
Hawking's result of thermal radiation from black holes and the connection
between quantum black holes and thermodynamics has shed some light for
new fundamental physics in which gravity, thermodynamics and QFT pull
all the strings. This could in turn lead to looking at physics with new eyes
and making advances that have some experimental checks. It is with this
motivation that we embark on a journey of understanding these historical
and path breaking results.
The motivation to study curved space QFT is multidimensional as a case
about it being a rst approximation to quantum gravity has been made.
The study of black holes and e ects like Hawking radiation are consistency
checks for many new theories like DBI theory, AdS/CFT duality thus anyone
interested exploring these elds must have a rm knowledge of curved space
QFT. Also the study of anomalies is central to the understanding of low
energy limit of string theories as well as statistical physics. This subject
consolidates previous knowledge and brings one to the doorstep of new and
exciting physics which is reason enough to pursue it.
