Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Reconstructing the dark energy equation of state with varying couplings   We revisit the idea of using varying couplings to probe the nature of dark
energy, in particular by reconstructing its equation of state. We show that
this method can be far superior to the standard methods (using type Ia
supernovae or weak lensing). We also show that the simultaneous use of
measurements of the fine-structure constant $\alpha$ and the electron-to-proton
mass ratio $\mu$ allows a direct probe of grand unification scenarios. We
present forecasts for the sensitivity of this method, both for the near future
and for the next generation of spectrographs -- for the latter we focus on the
planned CODEX instrument for ESO's Extremely Large Telescope (formerly known as
OWL). A high-accuracy reconstruction of the equation of state may be possible
all the way up to redshift $z\sim4$.

1
The categories of this paper are: cs
33
The categories of this paper are: plasm-ph
15
The categories of this paper are: nucl-ex
2
The categories of this paper are: math
23
The categories of this paper are: solv-int
25
The categories of this paper are: patt-sol
17
The categories of this paper are: q-fin
11
The categories of this paper are: hep-lat
8
The categories of this paper are: hep-ex
3
The categories of this paper are: physics
0
The categories of this paper are: hep-ph
36
The categories of this paper are: cmp-lg
22
The categories of this paper are: chao-dyn
10
The categories of this paper are: q-bio
35
The categories of this paper are: mtrl-th
19
The categories of this paper are: eess