Quantum phase transitions in holographic models of magnetism and superconductors

摘要: We study a holographic model realizing an ``antiferromagnetic'' phase in which global $SU(2)$ symmetry representing spin is broken down to $U(1)$ by the presence of finite electric charge density. This involves condensation neutral scalar field charged anti--de Sitter black hole. observe that transition for both and (as standard superconductor) order parameters can be driven zero temperature tuning UV conformal dimension parameter, resulting quantum Berezinskii-Kosterlitz-Thouless--type. also characterize antiferromagnetic externally forced ferromagnetic showing they contain expected waves with linear quadratic dispersions, respectively.