Holographic superconductor on Q-lattice

Journal of High Energy Physics, Feb 2015

We construct the simplest gravitational dual model of a superconductor on Q-lattices. We analyze the condition for the existence of a critical temperature at which the charged scalar field will condense. In contrast to the holographic superconductor on ionic lattices, the presence of Q-lattices will suppress the condensate of the scalar field and lower the critical temperature. In particular, when the Q-lattice background is dual to a deep insulating phase, the condensation would never occur for some small charges. Furthermore, we numerically compute the optical conductivity in the superconducting regime. It turns out that the presence of Q-lattice does not remove the pole in the imaginary part of the conductivity, ensuring the appearance of a delta function in the real part. We also evaluate the gap which in general depends on the charge of the scalar field as well as the Q-lattice parameters. Nevertheless, when the charge of the scalar field is relatively large and approaches the probe limit, the gap becomes universal with ω g ≃ 9T c which is consistent with the result for conventional holographic superconductors.

This is a preview of a remote PDF: https://link.springer.com/content/pdf/10.1007%2FJHEP02%282015%29059.pdf

Yi Ling, Peng Liu, Chao Niu, Jian-Pin Wu, Zhuo-Yu Xian. Holographic superconductor on Q-lattice, Journal of High Energy Physics, 2015, 59, DOI: 10.1007/JHEP02(2015)059