In May 2024, Physical Review D published an article by a team of scientists from the Laboratory of Theoretical Physics at JINR and the University of Zurich (Switzerland), which focuses on the study of quantum chromodynamics (QCD) equation of state in external magnetic field and nonzero baryon density. This research was conducted using lattice simulations with 2 + 1 dynamical staggered quarks at the physical masses.

The excess of pressure Δ⁢? = ?⁡(?_?) − ?⁡(?_? = 0) due to nonzero baryon density

By conducting a simulation at imaginary baryon chemical potential, scientists were able to overcome the sign problem. They expanded the pressure in the baryon imaginary chemical potential and studied three leading nonzero coefficients in this expansion. These coefficients were calculated for the following values of magnetic field: eB = 0.3, 0.6, 1.2 GeV² with the lattice sizes 8 × 32³, 10 × 40³, 12 × 48³. Using the obtained data, the continuum limit for these coefficients was taken. The results of the study indicated considerable enhancement of the expansion coefficients by the magnetic field.

Read the full text of this paper via the link. Among the authors are JINR researchers Victor Braguta, Andrey Kotov and Artem Roenko.