Scalar Boundary Conditions in Hyperscaling Violating Geometry

We study the possible boundary conditions of scalar field modes in a hyperscaling violation(HV) geometry with Lifshitz dynamical exponent $z (z\geqslant1)$ and hyperscaling violation exponent $\theta (\theta\neq0)$. For the case with $\theta>0$, we show that in the parameter range with $1\leq z\leq 2,~-z+d-12,~-z+d-1<\theta\leq d-1$, the boundary conditions have different types, including the Neumann, Dirichlet and Robin conditions, while in the range with $\theta\leq-z+d-1$, only Dirichlet type condition can be set. In particular, we further confirm that the mass of the scalar field does not play any role in determining the possible boundary conditions for $\theta>0$, which has been addressed in Ref. \cite{1201.1905}. Meanwhile, we also do the parallel investigation in the case with $\theta<0$. We find that for $m^2<0$, three types of boundary conditions are available, but for $m^2>0$, only one type is available.Comment: 19 page

Entanglement Entropy as a Probe of the Proximity Effect in Holographic Superconductors

We study the entanglement entropy as a probe of the proximity effect of a superconducting system by using the gauge/gravity duality in a fully back-reacted gravity system. While the entanglement entropy in the superconducting phase is less than the entanglement entropy in the normal phase, we find that near the contact interface of the superconducting to normal phase the entanglement entropy has a different behavior due to the leakage of Cooper pairs to the normal phase. We verify this behavior by calculating the conductivity near the boundary interface.Comment: 10 pages, 7 figures, extended version to be published in JHE

The Effect of the Gauss-Bonnet term to Hawking Radiation from arbitrary dimensional Black Brane

We investigate the probabilities of the tunneling and the radiation spectrums of the massive spin-1 particles from arbitrary dimensional Gauss-Bonnet-Axions (GBA) Anti-de Sitter (AdS) black brane, via using the WKB approximation to the Proca spin-1 field equation. The tunneling probabilities and Hawking temperature of the arbitrary dimensional GBA AdS black brane is calculated via the Hamilton-Jacobi approach. We also compute the Hawking temperature via Parikh-Wilczek tunneling approach. The results obtained from the two methods are consistent. In our setup, the Gauss-Bonnet (GB) coupling affects the Hawking temperature if and only if the momentum of axion fields is non-vanishing.Comment: 11 pages; version 2,references added; published versio