Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Evading the non-continuity equation in the f(R, T) formalism   We present a new approach for the $f(R,T)$ formalism, by exploring the extra
terms of its effective energy-momentum tensor $T_{\mu\nu}^{eff}$, namely
$\tilde{T}_{\mu\nu}$. Those arise from the consideration of quantum effects,
which are usually neglected in general relativity and $f(R)$ theories, and are
summed to the usual matter energy-momentum tensor, yielding
$T_{\mu\nu}^{eff}=T_{\mu\nu}+\tilde{T}_{\mu\nu}$. Purely from the Bianchi
identities, the conservation of both parts of the effective energy-momentum
tensor is obtained, rather than the non-conservation of the matter one,
originally approached in the $f(R,T)$ theories. In this way, the intriguing
scenario of matter-creation, which still lacks observational evidences, is
evaded. One is left, then, with two sets of cosmological equations to be
solved: the Friedmann-like equations along with the conservation of
$T_{\mu\nu}$ and along with the conservation of $\tilde{T}_{\mu\nu}$. We
present a physical interpretation for the conservation of the extra terms of
the effective energy-momentum tensor, which is related to the presence of stiff
matter in the universe. The cosmological features of this approach are
presented and discussed as well as the benefits of evading the matter
energy-momentum tensor non-conservation.

1
The categories of this paper are: cs
31
The categories of this paper are: ao-sci
7
The categories of this paper are: hep-th
10
The categories of this paper are: q-bio
29
The categories of this paper are: funct-an
35
The categories of this paper are: mtrl-th
37
The categories of this paper are: supr-con
18
The categories of this paper are: econ
24
The categories of this paper are: dg-ga
22
The categories of this paper are: chao-dyn
36
The categories of this paper are: cmp-lg
0
The categories of this paper are: hep-ph
26
The categories of this paper are: bayes-an
27
The categories of this paper are: comp-gas
32
The categories of this paper are: atom-ph
15
The categories of this paper are: nucl-ex