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We demonstrate that AdS_5 x T^{pq} is unstable, in the sense of Breitenlohner and Freedman, for unequal p and q. This settles, negatively, the long-standing question of whether the T^{pq} manifolds for unequal p and q might correspond to non-supersymmetric fixed points of the renormalization group. We also show that the AdS_3 x S^7 vacuum of Sugimotos USp(32) open string theory is unstable. This explains, at a heuristic level, the apparent absence of a heterotic string dual.
In 4D general relativity, the angular momentum of a black hole is limited by the Kerr bound. We suggest that in string theory, this bound can be breached and compact black-hole-like objects can spin faster. Near such superspinars, the efficiency of e
In this paper, we introduce some interesting features of a memristor CNN (Cellular Neural Network). We first show that there is the similarity between the dynamics of memristors and neurons. That is, some kind of flux-controlled memristors can not re
This is a review of some of the interesting properties of the Riemann Zeta Function.
In this work we briefly review the Kovtun-Son-Starinet (KSS) computation of the ratio eta/s for quantum field theories with gravitational dual and the related conjecture that it is bound from below by 1/(4 pi). We discuss the validity of the bound an
The Lorentz- and CPT-violating Chern-Simons extension of electrodynamics is considered. In the context of N=4 supergravity in four spacetime dimensions, it is argued that cosmological solutions can generate this extension. Within Chern-Simons electro