Temperature and Disorder Chaos in Three-Dimensional Ising Spin Glasses

We study the effects of small temperature as well as disorder perturbations on the equilibrium state of three-dimensional Ising spin glasses via an alternate scaling ansatz. By using Monte Carlo simulations, we show that temperature and disorder perturbations yield chaotic changes in the equilibrium state and that temperature chaos is considerably harder to observe than disorder chaos.Comment: 4 pages, 3 figures, 1 tabl

Reconstruction of Random Colourings

Reconstruction problems have been studied in a number of contexts including biology, information theory and and statistical physics. We consider the reconstruction problem for random $k$-colourings on the $\Delta$-ary tree for large $k$. Bhatnagar et. al. showed non-reconstruction when $\Delta \leq \frac12 k\log k - o(k\log k)$ and reconstruction when $\Delta \geq k\log k + o(k\log k)$. We tighten this result and show non-reconstruction when $\Delta \leq k[\log k + \log \log k + 1 - \ln 2 -o(1)]$ and reconstruction when $\Delta \geq k[\log k + \log \log k + 1+o(1)]$.Comment: Added references, updated notatio

5-Regular graphs are 3-colorable with positive probability

Abstract. We show that uniformly random 5-regular graphs of n vertices are 3-colorable with probability that is positive independently of n.

Modification of a Ti-Mo alloy surface via plasma electrolytic oxidation in a solution containing calcium and phosphorus

Investigations into the surface modification of a Ti-15Mo alloy via plasma electrolytic oxidation are reported. The oxidation process was conducted in a solution containing Ca(H2PO2)2, H 3PO4, or (HCOO)2Ca. Anodisation was performed at voltages in the range of 100-400 V. The morphology of the sample surface did not change during alloy oxidation at lower voltages. Higher voltages led to the incorporation of calcium and phosphorus or of calcium only into the formed oxide layer and to significant modification of the surface morphology. Based on the SEM and EDX analysis results, a set of samples was selected for further investigations. To study the surface of the Ti-Mo alloy after anodic oxidation, we used scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), thin-layer X-ray diffraction (TL-XRD), and X-ray photoelectron spectroscopy (XPS). The electrochemical characteristics of the modified alloy in Ringer's solution were determined. Anodisation results in a considerable increase in the corrosion resistance of the Ti-15Mo alloy. © 2013 Elsevier Ltd