Abstract
The equation of state of QCD matter at high densities is relevant for neutron star structure and for neutron star mergers and has been a focus of recent work. We show how lattice QCD simulations, free of sign problems, can provide an upper bound on the pressure as a function of quark chemical potentials. We show that at large chemical potentials this bound should become quite sharp; the difference between the upper bound on the pressure PPQ and the true pressure P is of order PPQ − P = \( \mathcal{O} \)(\( {\alpha}_{\textrm{s}}^3 \)P). The corrections arise from a single Feynman diagram; its calculation would render remaining corrections \( \mathcal{O} \)(\( {\alpha}_{\textrm{s}}^4 \)P).
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Acknowledgments
We would like to thank Gergely Endrődi and Saga Säppi for useful discussions. We acknowledge support by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) through the CRC-TR 211 “Strong-interaction matter under extreme conditions”– project number 315477589 – TRR 211, the DFG-Project ID 279384907-SFB 1245, and by the State of Hesse within the Research Cluster ELEMENTS (Project ID 500/10.006).
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Moore, G.D., Gorda, T. Bounding the QCD Equation of State with the Lattice. J. High Energ. Phys. 2023, 133 (2023). https://doi.org/10.1007/JHEP12(2023)133
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DOI: https://doi.org/10.1007/JHEP12(2023)133