Speaker
Description
A longstanding obstacle to mapping the phase diagram of quantum chromodynamics (QCD) in the temperature–baryon density plane is the Sign Problem of lattice Monte Carlo—the only reliable nonperturbative, first-principles approach to QCD. However, it is known that nonperturbative inequalities bound the thermodynamic pressure of QCD matter by that of its phase-quenched (PQ) version—a Sign-Problem-free theory amenable to lattice treatment.
In the high-density regime, the leading perturbative difference between the pressures of the QCD and PQ theories reduces to a single four-loop Feynman diagram. This makes it possible to determine the thermodynamics of QCD from PQ lattice simulations with high precision in the regime where this difference is small.
In this talk, we report on the evaluation of this perturbative difference at finite temperature and density, discuss the role played by quark pairing, and examine the general structure of the weak-coupling expansion, enabling to determine the QCD pressure to unprecedented orders in the strong coupling constant.