Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: One-loop $\lambda \phi^4$ theory in Robertson-Walker spacetimes:
  adiabatic regularization and analytic approximation   The renormalization of a scalar field theory with a quartic self-coupling (a
$\lambda \phi^4$ theory) via adiabatic regularization in a general
Robertson-Walker spacetime is discussed. The adiabatic counterterms are
presented in a way that is most conducive to numerical computations. A
variation of the adiabatic regularization method is presented which leads to
analytic approximations for the energy-momentum tensor of the field and the
quantum contribution to the effective mass of the mean field. Conservation of
the energy-momentum tensor for the field is discussed and it is shown that the
part of the energy-momentum tensor which depends only on the mean field is not
conserved but the full renormalized energy-momentum tensor is conserved as
expected and required by the semiclassical Einstein's equation. It is also
shown that if the analytic approximations are used then the resulting
approximate energy-momentum tensor is conserved. This allows a self-consistent
backreaction calculation to be performed using the analytic approximations. The
usefulness of the approximations is discussed.

22
The categories of this paper are: chao-dyn
1
The categories of this paper are: cs
13
The categories of this paper are: quant-ph
9
The categories of this paper are: nlin
30
The categories of this paper are: q-alg
12
The categories of this paper are: nucl-th
18
The categories of this paper are: econ
6
The categories of this paper are: astro-ph
14
The categories of this paper are: math-ph
32
The categories of this paper are: atom-ph
27
The categories of this paper are: comp-gas
4
The categories of this paper are: cond-mat
23
The categories of this paper are: solv-int
2
The categories of this paper are: math
19
The categories of this paper are: eess
35
The categories of this paper are: mtrl-th