Stability of Horava-Lifshitz Black Holes in the Context of AdS/CFT

The anti--de Sitter/conformal field theory (AdS/CFT) correspondence is a powerful tool that promises to provide new insights toward a full understanding of field theories under extreme conditions, including but not limited to quark-gluon plasma, Fermi liquid and superconductor. In many such applications, one typically models the field theory with asymptotically AdS black holes. These black holes are subjected to stringy effects that might render them unstable. Ho\v{r}ava-Lifshitz gravity, in which space and time undergo different transformations, has attracted attentions due to its power-counting renormalizability. In terms of AdS/CFT correspondence, Ho\v{r}ava-Lifshitz black holes might be useful to model holographic superconductors with Lifshitz scaling symmetry. It is thus interesting to study the stringy stability of Ho\v{r}ava-Lifshitz black holes in the context of AdS/CFT. We find that uncharged topological black holes in $\lambda=1$ Ho\v{r}ava-Lifshitz theory are nonperturbatively stable, unlike their counterparts in Einstein gravity, with the possible exceptions of negatively curved black holes with detailed balance parameter $\epsilon$ close to unity. Sufficiently charged flat black holes for $\epsilon$ close to unity, and sufficiently charged positively curved black holes with $\epsilon$ close to zero, are also unstable. The implication to the Ho\v{r}ava-Lifshitz holographic superconductor is discussed.Comment: 15 pages, 6 figures. Updated version accepted by Phys. Rev. D, with corrections to various misprints. References update

Reply to ``Comment on `Insulating Behavior of λ\lambda-DNA on the Micron Scale' "

In our experiment, we found that the resistance of vacuum-dried $\lambda$-DNA exceeds $10^{14} \Omega$ at 295 K. Bechhoefer and Sen have raised a number of objections to our conclusion. We provide counter arguments to support our original conclusion.Comment: 1 page reply to comment, 1 figur

Variations in bilingual processing of positive and negative information

Past research suggests that the emotional content of words has greater impact when presented in a bilingual's first language (L1) compared to their second language (L2). This is predicted to be a consequence of automatic processing of emotional words in L1 compared to slower, semantic processing in L2. In the current study 58 Chinese-English bilinguals from Hong Kong rated the valence and arousal of positive, neutral, and negative words presented in Chinese (L1) and English (L2). In contrast to predictions, perceived emotionality of the words was higher in L2, with positive words rated more positively and negative words rated more negatively when presented in English compared to Chinese. The findings suggest that words presented in L2 did not have lower emotional impact than L1, the results indicate that emotional processing of words may be influenced by language proficiency and language complexity

A MOS-based Dynamic Memetic Differential Evolution Algorithm for Continuous Optimization: A Scalability Test

Continuous optimization is one of the areas with more activity in the field of heuristic optimization. Many algorithms have been proposed and compared on several benchmarks of functions, with different performance depending on the problems. For this reason, the combination of different search strategies seems desirable to obtain the best performance of each of these approaches. This contribution explores the use of a hybrid memetic algorithm based on the multiple offspring framework. The proposed algorithm combines the explorative/exploitative strength of two heuristic search methods that separately obtain very competitive results. This algorithm has been tested with the benchmark problems and conditions defined for the special issue of the Soft Computing Journal on Scalability of Evolutionary Algorithms and other Metaheuristics for Large Scale Continuous Optimization Problems. The proposed algorithm obtained the best results compared with both its composing algorithms and a set of reference algorithms that were proposed for the special issue

Epidermal transient receptor potential vanilloid 1 in idiopathic small nerve fibre disease, diabetic neuropathy and healthy human subjects

10.1111/j.1365-2559.2007.02851.xHistopathology515674-68

Polarons in the radio-frequency spectrum of a quasi-two-dimensional Fermi gas

We measure radio-frequency spectra for a two-component mixture of a $^6$Li atomic Fermi gas in the quasi-two-dimensional regime. Near the Feshbach resonance, where the transverse Fermi energy is large compared to the confinement-induced dimer binding energies for the initial and final states, we find that the observed resonances do not correspond to transitions between confinement-induced dimers. The spectrum appears to be well-described by transitions between noninteracting polaron states in two dimensions.Comment: 5 pages, 4 figures and supplementary material 4 pages, 3 figure

Geometric Approach to Lyapunov Analysis in Hamiltonian Dynamics

As is widely recognized in Lyapunov analysis, linearized Hamilton's equations of motion have two marginal directions for which the Lyapunov exponents vanish. Those directions are the tangent one to a Hamiltonian flow and the gradient one of the Hamiltonian function. To separate out these two directions and to apply Lyapunov analysis effectively in directions for which Lyapunov exponents are not trivial, a geometric method is proposed for natural Hamiltonian systems, in particular. In this geometric method, Hamiltonian flows of a natural Hamiltonian system are regarded as geodesic flows on the cotangent bundle of a Riemannian manifold with a suitable metric. Stability/instability of the geodesic flows is then analyzed by linearized equations of motion which are related to the Jacobi equations on the Riemannian manifold. On some geometric setting on the cotangent bundle, it is shown that along a geodesic flow in question, there exist Lyapunov vectors such that two of them are in the two marginal directions and the others orthogonal to the marginal directions. It is also pointed out that Lyapunov vectors with such properties can not be obtained in general by the usual method which uses linearized Hamilton's equations of motion. Furthermore, it is observed from numerical calculation for a model system that Lyapunov exponents calculated in both methods, geometric and usual, coincide with each other, independently of the choice of the methods.Comment: 22 pages, 14 figures, REVTeX