https://doi.org/10.1140/epjp/s13360-023-03696-w
Regular Article
Speed of sound in QCD matter at finite temperature and density
1
School of Physics, Xi’an Jiaotong University, 710049, Xi’an, Shaaxi, China
2
School of Physics, Peking University, 100871, Beijing, China
Received:
19
October
2022
Accepted:
10
January
2023
Published online:
18
January
2023
The speed of sound in QCD matter at finite temperature and density is investigated within the Polyakov loop improved Nambu–Jona-Lasinio model. The spinodal structure associated with the first-order chiral phase transition is considered to describe the continuous variation of the speed of sound. The behaviors of the squared sound speed in different phases, including the stable, metastable and unstable phases, are derived. The relation between speed of sound and QCD phase transitions is systematically explored. In particular, the boundary of vanishing sound velocity is derived in the temperature-density phase diagram, and the region where the sound wave equation being broken is pointed out. Some interesting features of speed of sound under different definitions are also discussed.
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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2023. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
