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The QCD equation of state in background magnetic fields

  • G. S. Bali
  • F. Bruckmann
  • G. EndrődiEmail author
  • S. D. Katz
  • A. Schäfer
Open Access
Article

Abstract

We determine the equation of state of 2+1-flavor QCD with physical quark masses, in the presence of a constant (electro)magnetic background field on the lattice. To determine the free energy at nonzero magnetic fields we develop a new method, which is based on an integral over the quark masses up to asymptotically large values where the effect of the magnetic field can be neglected. The method is compared to other approaches in the literature and found to be advantageous for the determination of the equation of state up to large magnetic fields. Thermodynamic observables including the longitudinal and transverse pressure, magnetization, energy density, entropy density and interaction measure are presented for a wide range of temperatures and magnetic fields, and provided in ancillary files. The behavior of these observables confirms our previous result that the transition temperature is reduced by the magnetic field. We calculate the magnetic susceptibility and permeability, verifying that the thermal QCD medium is paramagnetic around and above the transition temperature, while we also find evidence for weak diamagnetism at low temperatures.

Keywords

Quark-Gluon Plasma Lattice QCD Phase Diagram of QCD 

Notes

Open Access

This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited.

Supplementary material

13130_2014_8782_MOESM1_ESM.dat (286 kb)
ESM 1 (DAT 285 kb)
13130_2014_8782_MOESM2_ESM.dat (8 kb)
ESM 2 (DAT 8 kb)

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Copyright information

© The Author(s) 2014

Authors and Affiliations

  • G. S. Bali
    • 1
    • 2
  • F. Bruckmann
    • 1
  • G. Endrődi
    • 1
    Email author
  • S. D. Katz
    • 3
    • 4
  • A. Schäfer
    • 1
  1. 1.Institute for Theoretical PhysicsUniversität RegensburgRegensburgGermany
  2. 2.Tata Institute of Fundamental ResearchMumbaiIndia
  3. 3.Eötvös University, Theoretical PhysicsBudapestHungary
  4. 4.MTA-ELTE Lendület Lattice Gauge Theory Research GroupBudapestHungary

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