Hagedorn spectrum and thermodynamics of SU(2) and SU(3) Yang-Mills theories

Understand

We present a high-precision lattice calculation of the equation of state in the confining phase of SU(2) Yang-Mills theory.

• We show that the results are described very well by a gas of massive, non-interacting glueballs, provided one assumes an exponentially growing Hagedorn spectrum.
• The latter can be derived within an effective bosonic closed-string model, leading to a parameter-free theoretical prediction, which is in perfect agreement with our lattice results.
• Furthermore, when applied to SU(3) Yang-Mills theory, this effective model accurately describes the lattice results reported by Bors\'anyi et al.