On the variable-charged black holes embedded into de Sitter space: Hawking's radiation

In this paper we study the Hawking evaporation of masses of variable-charged Reissner-Nordstrom and Kerr-Newman, black holes embedded into the de Sitter universe by considering the charge to be function of radial coordinate of the spherically symmetric metric.Comment: LaTex, p. 2

Towards quality control of food using terahertz

Copyright © 2007 SPIE - The International Society for Optical Engineering. Copyright 2007 Society of Photo-Optical Instrumentation Engineers. This paper was published in BioMEMS and Nanotechnology III, edited by Dan V. Nicolau, Derek Abbott, Kourosh Kalantar-Zadeh, Tiziana Di Matteo, Sergey M. Bezrukov, Proc. of SPIE Vol. 6799, 67991E and is made available as an electronic reprint with permission of SPIE. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.Terahertz radiation or T-rays, show promise in quality control of food products. As T-rays are inherently sensitive to water, they are very suitable for moisture detection. This proves to be a valuable asset in detecting the moisture content of dried food, a critical area for some products. As T-rays are transparent to plastics, food additives can also be probed through the packaging, providing checks against a manufacturer's claims, such as the presence of certain substances in foods.B. S. -Y. Ung and B. M. Fischer and B. W. -H. Ng and D. Abbot

Electron-spectroscopic investigation of metal-insulator transition in Sr2Ru1-xTixO4 (x=0.0-0.6)

We investigate the nature and origin of the metal-insulator transition in Sr2Ru1-xTixO4 as a function of increasing Ti content (x). Employing detailed core, valence, and conduction band studies with x-ray and ultraviolet photoelectron spectroscopies along with Bremsstrahlung isochromat spectroscopy, it is shown that a hard gap opens up for Ti content greater than equal to 0.2, while compositions with x<0.2 exhibit finite intensity at the Fermi energy. This establishes that the metal-insulator transition in this homovalent substituted series of compounds is driven by Coulomb interaction leading to the formation of a Mott gap, in contrast to transitions driven by disorder effects or band flling.Comment: Accepted for publication in Phys. Rev.

Wavelet transform and terahertz local tomography

Copyright © 2007 SPIE - The International Society for Optical Engineering. Copyright 2007 Society of Photo-Optical Instrumentation Engineers. This paper was published in Novel Optical Instrumentation for Biomedical Applications III, edited by Christian D. Depeursinge Proc. of SPIE-OSA Biomedical Optics, SPIE Vol. 6631, 663113 and is made available as an electronic reprint with permission of SPIE. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.We use the theory of two dimensional discrete wavelet transforms to derive inversion formulas for the Radon transform of terahertz datasets. These inversion formulas with good localised properties are implemented for the reconstruction of terahertz imaging in the area of interest, with a significant reduction in the required measurements. As a form of optical coherent tomography, terahertz CT complements the current imaging techniques and offers a promising approach for achieving non-invasive inspection of solid materials, with potentially numerous applications in industrial manufacturing and biomedical engineering. © 2007 SPIE-OSA.Xiaoxia Yin and Brian W.-H. Ng and Bradley Fergusona and Derek Abbot

Affleck-Dine Baryogenesis, Split Supersymmetry, and Inflation

It is shown that, in the context of split supersymmetry, a simple model with a single complex scalar field can produce chaotic inflation and generate the observed amount of baryon asymmetry via the Affleck-Dine mechanism. While the inflaton quantum fluctuations give rise to curvature perturbation, we show that quantum fluctuations of the phase of the scalar field can produce baryonic isocurvature perturbation. Combining with constraints from WMAP data, all parameters in the model can be determined to within a narrow range.Comment: version accepted for publication in PR

Information and Particle Physics

Information measures for relativistic quantum spinors are constructed to satisfy various postulated properties such as normalisation invariance and positivity. Those measures are then used to motivate generalised Lagrangians meant to probe shorter distance physics within the maximum uncertainty framework. The modified evolution equations that follow are necessarily nonlinear and simultaneously violate Lorentz invariance, supporting previous heuristic arguments linking quantum nonlinearity with Lorentz violation. The nonlinear equations also break discrete symmetries. We discuss the implications of our results for physics in the neutrino sector and cosmology

Topological spin excitations of Heisenberg antiferromagnets in two dimensions

In this paper we discuss the construction and the dynamics of vortex-like topological spin excitations in the Schwinger-boson description of Heisenberg antiferromagnets in two dimensions. The topological spin excitations are Dirac fermions (with gap) when spin value $S$ is a half-integer. Experimental and theoretical implications of these excitations are being investigated.Comment: Latex file, no figur

Clump Distance to the Magellanic Clouds and Anomalous Colors in the Galactic Bulge

I demonstrate that the two unexpected results in the local Universe: 1) anomalous intrinsic (V-I)_0 colors of the clump giants and RR Lyrae stars in the Galactic center, and 2) very short distances to the Magellanic Clouds (LMC, SMC) as inferred from clump giants, are connected with each other. The (V-I)_0 anomaly is partially resolved by using the photometry from the phase-II of the Optical Gravitational Lensing Experiment (OGLE) rather than phase-I. The need for V- or I-magnitude-based change in the bulge (V-I)_0 is one option to explain the remaining color discrepancy. Such change may originate in a coefficient of selective extinction A_V/E(V-I) smaller than typically assumed. Application of the (V-I)_0 correction (independent of its source) doubles the slope of the absolute magnitude - metallicity relation for clump giants, so that M_I(RC) = -0.23 + 0.19[Fe/H]. Consequently, the estimates of the clump distances to the LMC and SMC are affected. Udalski's (1998c) distance modulus of mu_{LMC} = 18.18 +/- 0.06 increases to mu_{LMC} = 18.27 +/- 0.07. The distance modulus to the SMC increases by 0.12 to mu_{SMC} = 18.77 +/- 0.08. I argue that a more comprehensive assessment of the metallicity effect on M_I(RC) is needed.Comment: accepted by ApJ Letters, brief review of the short distance scale dropped, discussion of the absolute magnitude - metallicity relation for clump giants shortened and made more qualitative, results basically unchange

Support vector machine applications in terahertz pulsed signals feature sets

Copyright © 2007 IEEE. All Rights Reserved.In the past decade, terahertz radiation (T-rays) have been extensively applied within the fields of industrial and biomedical imaging, owing to their noninvasive property. Support vector machine (SVM) learning algorithms are sufficiently powerful to detect patterns hidden inside noisy biomedical measurements. This paper introduces a frequency orientation component method to extract T-ray feature sets for the application of two- and multiclass classification using SVMs. Effective discriminations of ribonucleic acid (RNA) samples and various powdered substances are demonstrated. The development of this method has become important in T-ray chemical sensing and image processing, which results in enhanced detectability useful for many applications, such as quality control, security detection and clinic diagnosis.Xiaoxia Yin, Brian W.-H. Ng, Bernd M. Fischer, Bradley Ferguson, and Derek Abbot