Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Thermal Friction as a Solution to the Hubble Tension   A new component added to the standard model of cosmology that behaves like a
cosmological constant at early times and then dilutes away as radiation or
faster can resolve the Hubble tension. We show that a rolling axion coupled to
a non-Abelian gauge group exhibits the behavior of such an extra component at
the background level and can present a natural particle-physics model solution
to the Hubble tension. We compare the contribution of this bottom-up model to
the phenomenological fluid approximation and determine that CMB observables
sensitive only to the background evolution of the Universe are expected to be
similar in both cases, strengthening the case for this model to provide a
viable solution to the Hubble tension.

35
The categories of this paper are: mtrl-th
28
The categories of this paper are: alg-geom
31
The categories of this paper are: ao-sci
10
The categories of this paper are: q-bio
9
The categories of this paper are: nlin
3
The categories of this paper are: physics
2
The categories of this paper are: math
16
The categories of this paper are: stat
8
The categories of this paper are: hep-ex
17
The categories of this paper are: q-fin
20
The categories of this paper are: acc-phys
37
The categories of this paper are: supr-con
34
The categories of this paper are: chem-ph
27
The categories of this paper are: comp-gas
29
The categories of this paper are: funct-an
1
The categories of this paper are: cs