Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A New Guest in the Third Quantized Multiverse   In the present article we point out a conceptual issue of the Third
Quantization formalism for Canonical Quantum Gravity. Based on earlier results
on interuniversal entanglement, the picture of noninteracting
universe-antiuniverse pairs is incomplete. In particular, the variation of the
entanglement entropy with the scale factor, understood as a measure of time,
implies either an interaction between pairs of universes or universes with a
heat bath, i.e. an external field. We propose a simple solution to the problem
by adding a new quantum field to the formalism. Correspondingly, particles of
this field mediate interactions between universes -- depending on the model at
tree level or one loop -- and may further provide a heat bath in the
background.

12
The categories of this paper are: nucl-th
15
The categories of this paper are: nucl-ex
29
The categories of this paper are: funct-an
1
The categories of this paper are: cs
14
The categories of this paper are: math-ph
10
The categories of this paper are: q-bio
9
The categories of this paper are: nlin
27
The categories of this paper are: comp-gas
11
The categories of this paper are: hep-lat
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The categories of this paper are: chao-dyn
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The categories of this paper are: patt-sol
35
The categories of this paper are: mtrl-th
34
The categories of this paper are: chem-ph
24
The categories of this paper are: dg-ga
3
The categories of this paper are: physics
33
The categories of this paper are: plasm-ph