Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A no-go result for covariance in models of loop quantum gravity   Based on the observation that the exterior space-times of Schwarzschild-type
solutions allow two symmetric slicings, a static spherically symmetric one and
a timelike homogeneous one, modifications of gravitational dynamics suggested
by symmetry-reduced models of quantum cosmology can be used to derive
corresponding modified spherically symmetric equations. Generally covariant
theories are much more restricted in spherical symmetry compared with
homogeneous slicings, given by $1+1$-dimensional dilaton models if they are
local. As shown here, modifications used in loop quantum cosmology do not have
a corresponding covariant spherically symmetric theory. Models of loop quantum
cosmology therefore violate general covariance in the form of slicing
independence. Only a generalized form of covariance with a non-Riemannian
geometry could consistently describe space-time in models of loop quantum
gravity.

23
The categories of this paper are: solv-int
37
The categories of this paper are: supr-con
35
The categories of this paper are: mtrl-th
8
The categories of this paper are: hep-ex
33
The categories of this paper are: plasm-ph
24
The categories of this paper are: dg-ga
14
The categories of this paper are: math-ph
10
The categories of this paper are: q-bio
27
The categories of this paper are: comp-gas
3
The categories of this paper are: physics
16
The categories of this paper are: stat
12
The categories of this paper are: nucl-th
34
The categories of this paper are: chem-ph
18
The categories of this paper are: econ
29
The categories of this paper are: funct-an
0
The categories of this paper are: hep-ph