2,538 research outputs found

    On the Relativistic Formulation of Matter

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    A critical analysis of the relativistic formulation of matter reveals some surprising inconsistencies and paradoxes. Corrections are discovered which lead to the long-sought-after equality of the gravitational and inertial masses, which are otherwise different in general relativity. Realizing the potentially great impact of the discovered corrections, an overview of the situation is provided resulting from the newly discovered crisis, amid the evidences defending the theory.Comment: In press with Astrophys. Space Sci. (The final publication can be seen at springerlink.com

    A Machian Model of Dark Energy

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    Einstein believed that Mach's principle should play a major role in finding a meaningful spacetime geometry, though it was discovered later that his field equations gave some solutions which were not Machian. It is shown, in this essay, that the kinematical Λ\Lambda models, which are invoked to solve the cosmological constant problem, are in fact consistent with Mach's ideas. One particular model in this category is described which results from the microstructure of spacetime and seems to explain the current observations successfully and also has some benefits over the conventional models. This forces one to think whether the Mach's ideas and the cosmological constant are interrelated in some way.Comment: Received an Honorable mention in the Essay Contest-2002 sponsored by the Gravity Research Foundation; A paragraph added on how the model can explain the CMB anisotropy observations; To appear in the Classical and Quantum Gravit

    Modeling Repulsive Gravity with Creation

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    There is a growing interest in the cosmologists for theories with negative energy scalar fields and creation, in order to model a repulsive gravity. The classical steady state cosmology proposed by Bondi, Gold and Hoyle in 1948, was the first such theory which used a negative kinetic energy creation field to invoke creation of matter. We emphasize that creation plays very crucial role in cosmology and provides a natural explanation to the various explosive phenomena occurring in local (z<0.1) and extra galactic universe. We exemplify this point of view by considering the resurrected version of this theory - the quasi-steady state theory, which tries to relate creation events directly to the large scale dynamics of the universe and supplies more natural explanations of the observed phenomena. Although the theory predicts a decelerating universe at the present era, it explains successfully the recent SNe Ia observations (which require an accelerating universe in the standard cosmology), as we show in this paper by performing a Bayesian analysis of the data.Comment: The paper uses an old SNeIa dataset. With the new improved data, for example the updated gold sample (Riess et al, astro-ph/0611572), the fit improves considerably (\chi^2/DoF=197/180 and a probability of goodness-of-fit=18%

    Comparative Analysis of Free Space Optics and Single Mode Fiber

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    In this paper we have done comparative analysis of free space optics and single mode fibre optical channels system. Performance study is done for variable ranges 1km, 50km and 100km for the FSO and SMF channels. Single Mode Fiber and Free Space Optical Channel is observed that maximum Q factor, minimum bit error rate and signal power. FSO requires no licensing or frequency synchronization. It also provides the transmission of data with unlimited bandwidth. Results expose the ability of improving the Q factor by using these channels and the optimum effect concluded at (1km) length of optical rang by using the FSO channel i.e. the quality factor and signal power were increased to reach (1943 ) and (22.46dBm) respectively and MIN. BER is zero

    Converging Cylindrical Shock Waves in a Nonideal Gas With an Axial Magnetic Field

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    This paper analyses the propagation of converging cylindrical shock waves in a nonidealgas, in the presence of an axial magnetic field. Chester-Chisnell-Whitham’s method has beenemployed to determine the shock velocity and the other flow-variables just behind the shockin the cases, when (i) the gas is weakly ionised before and behind the shock front, (ii) the gasis strongly ionised before and behind the shock front, and (iii) nonionised gas undergoes intenseionisation as a result of the passage of the shock. The effects of the nonidealness of the gas,the conductivity of the gas, and the axial magnetic field have been investigated. It is found thatin the case (i), an increase in the value of parameter ( ) characterising the nonidealness of thegas accelerates the convergence of the shock. In the case (ii), the shock speed and pressurebehind the shock increase very fast as the axis is approached; and this increase occurs earlierif the strength of the initial magnetic field is increased. In the case (iii), for smaller values of theinitial magnetic field, the shock speed, and pressure behind the shock decrease very fast afterattaining a maximum; and for higher values of the initial magnetic field, the tendency of decreaseappears from the beginning. This shows that the magnetic field has damping effect on the shockpropagation. In the case (iii), it was also found that the growth of the shock in the initial phaseand decay in the last phase were faster when it was converging in a nonideal gas in comparisonwith that in a perfect gas. Further, it has been shown that the gas-ionising nature of the shockhas damping effect on its convergence

    Isothermal Shock Wave in Magnetogasdynamics

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    The problem of propagation of a plane isothermal discontinuity (shock) wave in a homogeneous semi-infinite body of a perfect gas, in the presence of amagnetic field have been solved. It has been shown that under certain definiteconditions, the density p at the wave front may be arbitrarily high for a singlecompression pulse. A certain class of solutions of the present problem for a nonhomogeneous semi-infinite body have been derived. Such solutions are expected to be of great importance in compression problems of plasma

    Interpretations of the Accelerating Universe

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    It is generally argued that the present cosmological observations support the accelerating models of the universe, as driven by the cosmological constant or `dark energy'. We argue here that an alternative model of the universe is possible which explains the current observations of the universe. We demonstrate this with a reinterpretation of the magnitude-redshift relation for Type Ia supernovae, since this was the test that gave a spurt to the current trend in favour of the cosmological constant.Comment: 12 pages including 2 figures, minor revision, references added, a paragraph on the interpretation of the CMB anisotropy in the QSSC added in conclusion, general results unchanged. To appear in the October 2002 issue of the "Publications of the Astronmical Society of the Pacific
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