Speaker
Description
Major progress has been made in recent years toward computing the four-loop perturbative pressure of cold and dense quark matter (QM) [1,2], a key ingredient in constraining the equation of state of neutron-star matter. What remains to be computed is the contribution from hard-momentum gluons in dense QCD, encoded in the sum of 52 four-loop vacuum Feynman diagrams at finite baryon chemical potential.
In this talk, we present recent advances in tackling this challenging calculation [3]. Our approach involves classifying the distinct contributions, isolating a subset of graphs responsible for infrared divergences, and demonstrating the feasibility of the novel dense Loop-Tree Duality (dLTD) method in the numerical evaluation of dense integrals at the four-loop level [4]. This will ultimately lead to the first completed loop order in almost five decades, a milestone result with significant impact in constraining the neutron-star-matter equation of state.
[1] Phys.Rev.Lett. 127 (2021) 16, 162003
[2] Phys.Rev.Lett. 131 (2023) 18, 181902
[3] arXiv:2501.17921
[4] Phys.Rev.D 110 (2024) 9, 094033
