The EMBH model in GRB 991216 and GRB 980425

This is a summary of the two talks presented at the Rome GRB meeting by C.L. Bianco and R. Ruffini. It is shown that by respecting the Relative Space-Time Transformation (RSTT) paradigm and the Interpretation of the Burst Structure (IBS) paradigm, important inferences are possible: a) in the new physics occurring in the energy sources of GRBs, b) on the structure of the bursts and c) on the composition of the interstellar matter surrounding the source.Comment: 8 pages, 3 figures, in the Proceedings of the "Third Rome Workshop on Gamma-Ray Bursts in the Afterglow Era", 17-20 September 2002, M. Feroci, F. Frontera, N. Masetti, L. Piro (editors

On the physical processes which lie at the bases of time variability of GRBs

The relative-space-time-transformation (RSTT) paradigm and the interpretation of the burst-structure (IBS) paradigm are applied to probe the origin of the time variability of GRBs. Again GRB 991216 is used as a prototypical case, thanks to the precise data from the CGRO, RXTE and Chandra satellites. It is found that with the exception of the relatively inconspicuous but scientifically very important signal originating from the initial ``proper gamma ray burst'' (P-GRB), all the other spikes and time variabilities can be explained by the interaction of the accelerated-baryonic-matter pulse with inhomogeneities in the interstellar matter. This can be demonstrated by using the RSTT paradigm as well as the IBS paradigm, to trace a typical spike observed in arrival time back to the corresponding one in the laboratory time. Using these paradigms, the identification of the physical nature of the time variablity of the GRBs can be made most convincingly. It is made explicit the dependence of a) the intensities of the afterglow, b) the spikes amplitude and c) the actual time structure on the Lorentz gamma factor of the accelerated-baryonic-matter pulse. In principle it is possible to read off from the spike structure the detailed density contrast of the interstellar medium in the host galaxy, even at very high redshift.Comment: 11 pages, 5 figure

Scaling analysis of Schottky barriers at metal-embedded semiconducting carbon nanotube interfaces

We present an atomistic self-consistent tight-binding study of the electronic and transport properties of metal-semiconducting carbon nanotube interfaces as a function of the nanotube channel length when the end of the nanotube wire is buried inside the electrodes. We show that the lineup of the nanotube band structure relative to the metal Fermi-level depends strongly on the metal work function but weakly on the details of the interface. We analyze the length-dependent transport characteristics, which predicts a transition from tunneling to thermally-activated transport with increasing nanotube channel length.Comment: To appear in Phys.Rev.B Rapid Communications. Color figures available in PRB online versio

Experimentally obtaining the Likeness of Two Unknown Quantum States on an NMR Quantum Information Processor

Recently quantum states discrimination has been frequently studied. In this paper we study them from the other way round, the likeness of two quantum states. The fidelity is used to describe the likeness of two quantum states. Then we presented a scheme to obtain the fidelity of two unknown qubits directly from the integral area of the spectra of the assistant qubit(spin) on an NMR Quantum Information Processor. Finally we demonstrated the scheme on a three-qubit quantum information processor. The experimental data are consistent with the theoretical expectation with an average error of 0.05, which confirms the scheme.Comment: 3 pages, 4 figure

MvSSIM: A quality assessment index for hyperspectral images

Quality assessment indexes play a fundamental role in the analysis of hyperspectral image (HSI) cubes. To assess the quality of an HSI cube, the structural similarity (SSIM) index has been widely applied in a band-by-band manner, as SSIM was originally designed for 2D images, and then the mean SSIM (MeanSSIM) index over all bands is adopted. MeanSSIM fails to accommodate the spectral structure which is a unique characteristic of HSI. Hence in this paper, we propose a new and simple multivariate SSIM (MvSSIM) index for HSI, by treating the pixel spectrum as a multivariate random vector. MvSSIM maintains SSIM’s ability to assess the spatial structural similarity via correlation between two images of the same band; and adds an ability to assess the spectral structural similarity via covariance among different bands. MvSSIM is well founded on multivariate statistics and can be easily implemented through simple sample statistics involving mean vectors, covariance matrices and cross-covariance matrices. Experiments show that MvSSIM is a proper quality assessment index for distorted HSIs with different kinds of degradations

GRB 970228 Within the EMBH Model

We consider the gamma-ray burst of 1997 February 28 (GRB 970228) within the ElectroMagnetic Black Hole (EMBH) model. We first determine the value of the two free parameters that characterize energetically the GRB phenomenon in the EMBH model, that is to say the dyadosphere energy, $E_{dya}=5.1\times10^{52}$ ergs, and the baryonic remnant mass $M_{B}$ in units of $E_{dya}$, $B=M_{B}c^{2}/E_{dya}=3.0\times10^{-3}$. Having in this way estimated the energy emitted during the beam-target phase, we evaluate the role of the InterStellar Medium (ISM) number density (n$_{ISM}$) and of the ratio ${\cal R}$ between the effective emitting area and the total surface area of the GRB source, in reproducing the observed profiles of the GRB 970228 prompt emission and X-ray (2-10 keV energy band) afterglow. The importance of the ISM distribution three-dimensional treatment around the central black hole is also stressed in this analysis.Comment: 4 pages, 1 figure, to appear in the Proceedings of the Los Alamos "Gamma Ray Burst Symposium" in Santa Fe, New Mexico, September 8-12 2003 (AIP Conf. Ser.), CHAPTER: GRB Connection to Supernova

Testing the transition layer model of quasi-periodic oscillations in neutron star X-ray binarie

We compare the theoretical predictions of the transition layer model with some observational features of quasi-periodic oscillations (QPOs) in neutron star X-ray binaries. We found that the correlation between horizontal branch oscillation (HBO) frequencies and kilohertz (kHz) QPO frequencies, the difference between the low-frequency QPOs in atoll sources and HBOs in Z sources, and the correlation between the frequencies of low-frequency QPOs and break frequencies can be well explained by the transition layer model, provided the neutron star mass is around 1.4 solar mass and the angle between magnetosphere equator and accretion disk plane is around 6 degree. The observed decrease of peak separation between two kHz QPO frequencies with the increase of kHz QPO frequencies and the increase of QPO frequencies with the increase of inferred mass accretion rate are also consistent with the theoretical predictions of transition layer model. In addition, we derive a simple equation that can be adopted to estimate the angle ($\delta$) between magnetosphere equator and accretion disk plane by use of the simultaneously observed QPO frequency data. We estimate these angles, in the range of 4 to 8 degrees, for five Z sources and two atoll sources. The nearly constant $\delta$ value for each source, derived from the different sets of simultaneously observed QPO frequency data, provides a strong test of the theoretical model. Finally, we suggest that the similar transition layer oscillations may be also responsible for the observed QPOs in accretion-powered millisecond X-ray pulsar and Galactic black hole candidates.Comment: 10 pages, 5 figures, to appear in ApJ, Vol. 55

On Hypothesis Testing for Comparing Image Quality Assessment Metrics [Tips & Tricks]

In developing novel image quality assessment (IQA) metrics, researchers should compare their proposed metrics with state-of-the-art metrics. A commonly adopted approach is by comparing two residuals between the nonlinearly mapped scores of two IQA metrics and the difference mean opinion score, which are assumed from Gaussian distributions with zero means. An F-test is then used to test the equality of variances of the two sets of residuals. If the variances are significantly different, then we conclude that the residuals are from different Gaussian distributions and that the two IQA metrics are significantly different. The F-test assumes that the two sets of residuals are independent. However, given that the IQA metrics are calculated on the same database, the two sets of residuals are paired and may be correlated. We note this improper usage of the F-test by practitioners, which can result in misleading comparison results of two IQA metrics. To solve this practical problem, we introduce the Pitman test to investigate the equality of variances for two sets of correlated residuals. Experiments on the Laboratory for Image and Video Engineering (LIVE) database show that the two tests can provide different conclusions