Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Reproduction of the charge density wave phase diagram in
  $1T$-$\mathrm{TiSe}_2$ exposes its excitonic character   Recent experiments suggest that excitonic degrees of freedom play an
important role in precipitating the charge density wave (CDW) transition in
$1T$-$\mathrm{TiSe}_2$. Through systematic calculations of the electronic and
phonon spectrum based on density functional perturbation theory, we show that
the predicted critical doping of the CDW phase overshoots the experimental
value by 1 order of magnitude. In contrast, an independent self-consistent
many-body calculation of the excitonic order parameter and renormalized band
structure is able to capture the experimental phase diagram in extremely good
qualitative and quantitative agreement. This demonstrates that
electron-electron interactions and the excitonic instability arising from
direct electron-hole coupling are pivotal to accurately describe the nature of
the CDW in this system. This has important implications to understand the
emergence of superconductivity within the CDW phase of this and related
systems.

2
The categories of this paper are: math
29
The categories of this paper are: funct-an
23
The categories of this paper are: solv-int
21
The categories of this paper are: adap-org
15
The categories of this paper are: nucl-ex
28
The categories of this paper are: alg-geom
34
The categories of this paper are: chem-ph
18
The categories of this paper are: econ
6
The categories of this paper are: astro-ph
20
The categories of this paper are: acc-phys
17
The categories of this paper are: q-fin
9
The categories of this paper are: nlin
10
The categories of this paper are: q-bio
7
The categories of this paper are: hep-th
31
The categories of this paper are: ao-sci
19
The categories of this paper are: eess