Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Hadronic and Quark-Gluon Excitations of Dense and Hot Matter   We summarize recent developments in our understanding of low-mass
quark-antiquark excitations in hadronic matter under various different
conditions. This includes the thermodynamics of the chiral condensate, pions as
Goldstone bosons in normal nuclear matter, and excursions into extreme
territory of the QCD phase diagram: lepton pair production from a fireball
expanding through the transition boundary between the quark-gluon and hadron
pha ses of QCD.

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
14
The categories of this paper are: math-ph
18
The categories of this paper are: econ
17
The categories of this paper are: q-fin
7
The categories of this paper are: hep-th
30
The categories of this paper are: q-alg
12
The categories of this paper are: nucl-th
1
The categories of this paper are: cs
4
The categories of this paper are: cond-mat
25
The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
34
The categories of this paper are: chem-ph
31
The categories of this paper are: ao-sci
32
The categories of this paper are: atom-ph