Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Big Bang Nucleosynthesis constraints on Barrow entropy   We use Big Bang Nucleosynthesis (BBN) data in order to impose constraints on
the exponent of Barrow entropy. The latter is an extended entropy relation
arising from the incorporation of quantum-gravitational effects on the
black-hole structure, parameterized effectively by the new parameter $\Delta$.
When considered in a cosmological framework and under the light of the
gravity-thermodynamics conjecture, Barrow entropy leads to modified
cosmological scenarios whose Friedmann equations contain extra terms. We
perform a detailed analysis of the BBN era and we calculate the deviation of
the freeze-out temperature comparing to the result of standard cosmology. We
use the observationally determined bound on $ |\frac{\delta {T}_f}{{T}_f}|$ in
order to extract the upper bound on $\Delta$. As we find, the Barrow exponent
should be inside the bound $\Delta\lesssim 1.4\times 10^{-4}$ in order not to
spoil the BBN epoch, which shows that the deformation from standard
Bekenstein-Hawking expression should be small as expected.

15
The categories of this paper are: nucl-ex
22
The categories of this paper are: chao-dyn
21
The categories of this paper are: adap-org
24
The categories of this paper are: dg-ga
20
The categories of this paper are: acc-phys
8
The categories of this paper are: hep-ex
13
The categories of this paper are: quant-ph
25
The categories of this paper are: patt-sol
18
The categories of this paper are: econ
33
The categories of this paper are: plasm-ph
31
The categories of this paper are: ao-sci
28
The categories of this paper are: alg-geom
36
The categories of this paper are: cmp-lg
3
The categories of this paper are: physics
27
The categories of this paper are: comp-gas
30
The categories of this paper are: q-alg