Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Model for a time-symmetric Milne-like universe without big bang
  curvature singularity   We present a physics model for a time-symmetric Milne-like universe. The
model is based on the $q$-theory approach to the cosmological constant problem,
supplemented by an assumed vacuum-matter energy exchange possibly due to
quantum-dissipative effects. Without fine-tuning of the initial vacuum energy
density, we obtain a harmless big bang singularity (with finite values of the
Ricci and Kretschmann curvature scalars) and attractor behavior towards
Minkowski spacetime. The time-symmetric spacetime manifold of our model may
provide the proper setting for a possible CPT-symmetric universe.

19
The categories of this paper are: eess
0
The categories of this paper are: hep-ph
25
The categories of this paper are: patt-sol
18
The categories of this paper are: econ
8
The categories of this paper are: hep-ex
13
The categories of this paper are: quant-ph
6
The categories of this paper are: astro-ph
11
The categories of this paper are: hep-lat
4
The categories of this paper are: cond-mat
3
The categories of this paper are: physics
10
The categories of this paper are: q-bio
27
The categories of this paper are: comp-gas
24
The categories of this paper are: dg-ga
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
2
The categories of this paper are: math