Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the Semiclassical Approach to Quantum Cosmology   The emergent semiclassical time approach to resolving the problem of time in
quantum gravity involves heavy slow degrees of freedom providing via an
approximately Hamilton-Jacobi equation an approximate timestandard with respect
to which the quantum mechanics of light fast degrees of freedom can run. More
concretely, this approach involves Born-Oppenheimer and WKB ansatze and some
accompanying approximations. In this paper, I investigate this approach for
concrete scaled relational particle mechanics models, i.e. models featuring
only relative separations, relative angles and relative times. I consider the
heavy-light interaction term in the light quantum equation - necessary for the
semiclassical approach to work, firstly as an emergent-time dependent
perturbation of the emergent-time-dependent Schrodinger equation for the light
subsystem. Secondly, I consider a scheme in which the backreaction is small but
non-negligible, so that the l-subsystem also affects the form of the emergent
time. I also suggest that the many terms involving expectation values of the
light wavefunctions in both the (unapproximated) heavy and light equations
might require treatment in parallel to the Hartree--Fock self-consistent
approach rather than merely being discarded; for the moment this paper provides
a counterexample to such terms being smaller than their unaveraged
counterparts. Investigation of these ideas and methods will give us a more
robust understanding of the suggested quantum-cosmological origin of microwave
background inhomogeneities and galaxies.

3
The categories of this paper are: physics
1
The categories of this paper are: cs
30
The categories of this paper are: q-alg
4
The categories of this paper are: cond-mat
13
The categories of this paper are: quant-ph
2
The categories of this paper are: math
22
The categories of this paper are: chao-dyn
31
The categories of this paper are: ao-sci
29
The categories of this paper are: funct-an
14
The categories of this paper are: math-ph
18
The categories of this paper are: econ
35
The categories of this paper are: mtrl-th
6
The categories of this paper are: astro-ph
34
The categories of this paper are: chem-ph
17
The categories of this paper are: q-fin
28
The categories of this paper are: alg-geom