Quantum Information Paradox: Real or Fictitious?

One of the outstanding puzzles of theoretical physics is whether quantum information indeed gets lost in the case of Black Hole (BH) evaporation or accretion. Let us recall that Quantum Mechanics (QM) demands an upper limit on the acceleration of a test particle. On the other hand, it is pointed out here that, if a Schwarzschild BH would exist, the acceleration of the test particle would blow up at the event horizon in violation of QM. Thus the concept of an exact BH is in contradiction of QM and quantum gravity (QG). It is also reminded that the mass of a BH actually appears as an INTEGRATION CONSTANT of Einstein equations. And it has been shown that the value of this integration constant is actually zero. Thus even classically, there cannot be finite mass BHs though zero mass BH is allowed. It has been further shown that during continued gravitational collapse, radiation emanating from the contracting object gets trapped within it by the runaway gravitational field. As a consequence, the contracting body attains a quasi-static state where outward trapped radiation pressure gets balanced by inward gravitational pull and the ideal classical BH state is never formed in a finite proper time. In other words, continued gravitational collapse results in an "Eternally Collapsing Object" which is a ball of hot plasma and which is asymptotically approaching the true BH state with M=0 after radiating away its entire mass energy. And if we include QM, this contraction must halt at a radius suggested by highest QM acceleration. In any case no EH is ever formed and in reality, there is no quantum information paradox.Comment: 8 pages in Pramana Style, 6 in Revtex styl

Altitude distribution, origin and flux of sodium in the atmosphere

Sodium equilibrium altitude distribution, origin, and flux calculated for earth atmospher

A co-operative parallel heuristic for integer linear programming: Combining simulated annealing with branch & bound

This paper considers the exact approach of branch and bound (B&B) and the metaheuristic known as simulated annealing (SA) for processing integer programs (IP). We extend an existing SA implementation (GPSIMAN) for pure zero–one integer programs (PZIP) to process a wider class of IP models, namely mixed zero–one integer programs (MZIP). The extensions are based on depth-first B&B searches at different points within the SA framework. We refer to the resultant SA implementation as MIPSA. Furthermore, we have exploited the use of parallel computers by designing a co-operative parallel heuristic whereby concurrent executions of B&B and MIPSA, linked through a parallel computer, exchange information in order to influence their searches. Results reported for a wide range of models taken from a library of MIP benchmarks demonstrate the effectiveness of using a parallel computing approach which combines B&B with SA

An integrative quantifier of multistability in complex systems based on ecological resilience

Acknowledgements This work was supported by the German Federal Ministry of Education and Research (BMBF) via the Young Investigators Group CoSy-CC2 (grant no. 01LN1306A). C.M. acknowledges the support of Bedartha Goswami, Jobst Heitzig and Tim Kittel.Peer reviewedPublisher PD

Comments on the paper ``Bare Quark Surfacees of Strange Stars and Electron-Positron Pair Emission''

In a recent paper (Ushov, PRL, 80, 230, 1998), it has been claimed that the bare surface of a strange star can emit electron-positron pairs of luminosity \~10^{51} ergs/s for about 10s. If true, obviously, this mechanism may explain the origin of cosmic Gamma Ray Bursts. However, we point out that such a mechanism is does not work because (i) if pair production really occurs the supposed pre-existing supercritical electric field will be quenched and this discharge process may at best release ~10^{24} ergs of electromagnetic energy, and (ii) there is no way by which the trapped core thermal energy of few 10^{52} ergs can be transmitted electromagnetically on a time scale of ~10s or even on a much larger time scale. The only way the hot core can cool on a time scale of ~10 s or much shorter is by the well known process of emission of nu-antinu pairs.Comment: Final version accepted in Phy. Rev. Lett. Main conclusion that the mechanism by Usov does not work remains unchanged, [email protected]

Current driven quantum criticality in itinerant electron ferromagnets

We determine the effect of an in-plane current flow on the critical properties of a 2d itinerant electron system near a ferromagnetic-paramagnetic quantum critical point. We study a model in which a nonequilibrium steady state is established as a result of exchange of particles and energy with an underlying substrate. the current $\vec{j}$ gives rise not only to an effective temperature equal to the voltage drop over a distance of order the mean free path, but also to symmetry breaking terms of the form $\vec{j}\cdot \vec{nabla}$ in the effective action. The effect of the symmetry breaking on the fluctuational and critical properties is found to be small although (in agreement with previous results) if rotational degrees of freedom are important, the current can make the classically ordered state dynamically unstable.Comment: 4 pages, published versio