Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Generalized Quantum Theory of Recollapsing Homogeneous Cosmologies   A sum-over-histories generalized quantum theory is developed for homogeneous
minisuperspace type A Bianchi cosmological models, focussing on the particular
example of the classically recollapsing Bianchi IX universe. The decoherence
functional for such universes is exhibited. We show how the probabilities of
decoherent sets of alternative, coarse-grained histories of these model
universes can be calculated. We consider in particular the probabilities for
classical evolution defined by a suitable coarse-graining. For a restricted
class of initial conditions and coarse grainings we exhibit the approximate
decoherence of alternative histories in which the universe behaves classically
and those in which it does not. For these situations we show that the
probability is near unity for the universe to recontract classically if it
expands classically. We also determine the relative probabilities of
quasi-classical trajectories for initial states of WKB form, recovering for
such states a precise form of the familiar heuristic "J d\Sigma" rule of
quantum cosmology, as well as a generalization of this rule to generic initial
states.

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The categories of this paper are: hep-ph
2
The categories of this paper are: math
35
The categories of this paper are: mtrl-th
23
The categories of this paper are: solv-int
8
The categories of this paper are: hep-ex
22
The categories of this paper are: chao-dyn
9
The categories of this paper are: nlin
20
The categories of this paper are: acc-phys
24
The categories of this paper are: dg-ga
15
The categories of this paper are: nucl-ex
33
The categories of this paper are: plasm-ph
1
The categories of this paper are: cs
27
The categories of this paper are: comp-gas
6
The categories of this paper are: astro-ph
26
The categories of this paper are: bayes-an
28
The categories of this paper are: alg-geom