Showing papers by "Eleftherios Papantonopoulos published in 2012"
TL;DR: In this article, the authors consider a gravitating system of vanishing cosmological constant consisting of an electromagnetic field and a scalar field coupled to the Einstein tensor and show that a Reissner-Nordstrom black hole undergoes a second-order phase transition to a hairy black hole of generally anisotropic hair at a certain critical temperature.
Abstract: We consider a gravitating system of vanishing cosmological constant consisting of an electromagnetic field and a scalar field coupled to the Einstein tensor. A Reissner–Nordstrom black hole undergoes a second-order phase transition to a hairy black hole of generally anisotropic hair at a certain critical temperature which we compute. The no-hair theorem is evaded due to the coupling between the scalar field and the Einstein tensor. Within a first-order perturbative approach, we calculate explicitly the properties of a hairy black hole configuration near the critical temperature and show that it is energetically favourable over the corresponding Reissner–Nordstrom black hole.
88 citations
TL;DR: In this article, a massive gravity theory which is Lorentz-violating all the way from ultraviolet to infrared energy scales is studied and a scalar perturbation analysis is performed, showing that the theory is healthy without ghosts, tachyons, strong coupling problems, and instabilities.
Abstract: We study a massive gravity theory which is Lorentz-violating all the way from ultraviolet to infrared energy scales. At short distances the theory breaks diffeomorphism invariance and time and space scale differently. Dynamical metric fields are introduced which, upon linearization over a Minkowski background, correspond to Lorentz-violating mass terms at large distances. We perform a scalar perturbation analysis and we show that with an appropriate choice of parameters, the theory is healthy without ghosts, tachyons, strong coupling problems, and instabilities.
12 citations
Posted Content•
TL;DR: In this article, the gravity dual of FFLO states in strongly coupled superconductors was discussed, and it was shown that in the high-field limit, an inhomogeneous solution possesses a higher critical temperature than the homogeneous case.
Abstract: We discuss the gravity dual of FFLO states in strongly coupled superconductors. The gravitational theory utilizes two U(1) gauge fields and a scalar field coupled to a charged AdS black hole. The first gauge field couples with the scalar sourcing a charge condensate below a critical temperature, and the second gauge field incorporates a magnetic field that couples to spin in the boundary theory. The scalar is neutral under the second gauge field. By turning on a magnetic interaction between the second U(1) field and the scalar, it is shown that, in the high-field limit, an inhomogeneous solution possesses a higher critical temperature than the homogeneous case, giving rise to FFLO states close to zero temperature.
6 citations