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arXiv · 1003.0010

Quantum phase transitions in holographic models of magnetism and superconductors

Nabil Iqbal·Hong Liu·Márk Mezei·Qimiao Si
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Abstract

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

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Nabil Iqbal, Hong Liu, Márk Mezei, Qimiao Si. 2010-03-04. Quantum phase transitions in holographic models of magnetism and superconductors. https://doi.org/10.1103/physrevd.82.045002

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