Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The structure in warm dense carbon   The structure of the fluid carbon phase in the pressure region of the
graphite, diamond, and BC8 solid phase is investigated. We find increasing
coordination numbers with an increase in density. From zero to $30$ GPa, the
liquid shows a decrease of packing efficiency with increasing temperature.
However, for higher pressures, the coordination number increases with
increasing temperature. Up to $1.5$ eV and independent of the pressure up to
$1000$ GPa, a double-peak structure in the ion structure factors exists,
indicating persisting covalent bonds. Over the whole pressure range from zero
to $1000$ GPa, the fluid structure and properties are strongly determined by
such covalent bonds.

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The categories of this paper are: quant-ph
32
The categories of this paper are: atom-ph
8
The categories of this paper are: hep-ex
6
The categories of this paper are: astro-ph
36
The categories of this paper are: cmp-lg
28
The categories of this paper are: alg-geom
17
The categories of this paper are: q-fin
25
The categories of this paper are: patt-sol
27
The categories of this paper are: comp-gas
10
The categories of this paper are: q-bio
24
The categories of this paper are: dg-ga
7
The categories of this paper are: hep-th
5
The categories of this paper are: gr-qc
30
The categories of this paper are: q-alg
9
The categories of this paper are: nlin
20
The categories of this paper are: acc-phys