QCD equation of state at nonzero baryon density in an external magnetic field
Nikita Astrakhantsev, V. V. Braguta, A. Yu. Kotov, A. A. Roenko
Abstract
This paper is devoted to the study of quantum chromodynamics (QCD) equation of state in external magnetic field and nonzero baryon density. Our study is carried out by means of lattice simulation with <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mn>2</a:mn><a:mo>+</a:mo><a:mn>1</a:mn></a:mrow></a:math> dynamical staggered quarks at the physical masses. The simulation is conducted at imaginary baryon chemical potential what allowed us to overcome the sign problem. We expand the pressure in the baryon imaginary chemical potential and study three leading nonzero coefficients in this expansion. These coefficients were calculated for the following values of magnetic field: <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mi>e</c:mi><c:mi>B</c:mi><c:mo>=</c:mo><c:mn>0.3</c:mn></c:math>, 0.6, <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:mrow><e:mn>1.2</e:mn><e:mtext> </e:mtext><e:mtext> </e:mtext><e:msup><e:mrow><e:mi>GeV</e:mi></e:mrow><e:mrow><e:mn>2</e:mn></e:mrow></e:msup></e:mrow></e:math> with the lattice sizes <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"><g:mn>8</g:mn><g:mo>×</g:mo><g:mn>3</g:mn><g:msup><g:mn>2</g:mn><g:mn>3</g:mn></g:msup></g:math>, <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"><i:mn>10</i:mn><i:mo>×</i:mo><i:mn>4</i:mn><i:msup><i:mn>0</i:mn><i:mn>3</i:mn></i:msup></i:math>, <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"><k:mn>12</k:mn><k:mo>×</k:mo><k:mn>4</k:mn><k:msup><k:mn>8</k:mn><k:mn>3</k:mn></k:msup></k:math>. Using these data we take continuum limit for the coefficients. Our results indicate considerable enhancement of the expansion coefficients by the magnetic field. Published by the American Physical Society 2024