2002/11/30 by K. Splittorff, J. T. Lenaghan, Jonathan Lenaghan +1
Mathematics · Physics and Astronomy · #Black Holes and Theoretical Physics #Chiral symmetry breaking #Critical phenomena #Effective field theory #High-Energy Particle Collisions Research #Homogeneous space #Isospin #Lorentz covariance #Lorentz transformation #Mathematics #Particle physics #Phase transition #Physics #Quantum Chromodynamics and Particle Interactions #Quantum chromodynamics #Quantum gravity #Quantum mechanics #Spontaneous symmetry breaking #Symmetry breaking #Theoretical physics #Thermal quantum field theory #hep-ph
paper · pdf · doi:10.1103/physrevd.67.105011
published as Phys.Rev. D67 (2003) 105011 · latex, 11 page, 1 figure, 1 table. Clarifications and one ref added. Version to appear in PRD
arxiv created 2003/04/18 · openalex publication_date 2003/05/21 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We discuss phase transitions in relativistic systems as a function of both the chemical potential and temperature. The presence of a chemical potential explicitly breaks Lorentz invariance and may additionally break other internal symmetries. This introduces new subtleties in the determination of the critical properties. We discuss separately three characteristic effects of a nonzero chemical potential. First, we consider only the explicit breaking of Lorentz invariance using a scalar field theory with a global U(1) symmetry. Second, we study the explicit breaking of an internal symmetry in addition to Lorentz invariance using two-color QCD at nonzero baryonic chemical potential. Finally, we consider the spontaneous breaking of a symmetry using three-color QCD at nonzero baryonic and isospin chemical potential. For each case, we derive the appropriate three-dimensional effective theory at criticality and study the effect of the chemical potential on the fixed point structure of the \ensuremathβ functions. We find that the order of the phase transition is not affected by the explicit breaking of Lorentz invariance but is sensitive to the breaking of additional symmetries by the chemical potential.