Evolution of Li, Be and B in the Galaxy

In this paper we study the production of Li, Be and B nuclei by Galactic cosmic ray spallation processes. We include three kinds of processes: (i) spallation by light cosmic rays impinging on interstellar CNO nuclei (direct processes); (ii) spallation by CNO cosmic ray nuclei impinging on interstellar p and 4He (inverse processes); and (iii) alpha-alpha fusion reactions. The latter dominate the production of 6Li and 7Li. We calculate production rates for a closed-box Galactic model, verifying the quadratic dependence of the Be and B abundances for low values of Z. These are quite general results and are known to disagree with observations. We then show that the multi-zone multi-population model we used previously for other aspects of Galactic evolution produces quite good agreement with the linear trend observed at low metallicities without fine tuning. We argue that reported discrepancies between theory and observations do not represent a nucleosynthetic problem, but instead are the consequences of inaccurate treatments of Galactic evolution.Comment: 26 pages, 5 figures, LaTeX. The Astrophysical Journal, in pres

Pelabelan Super Graceful Untuk Beberapa Graf Khusus

Given a graph , super graceful labeling is bijective function such that for every edge . A graph that has a super graceful labeling called a super graceful graph. In this final paper discuss about super graceful labeling for special graphs graph Pn , graph Pm(n) , graph Pn+-e1 , graph Cn n≥3 graph Pn1,2,…,n , graph Km,n , and graph Coconut tre

How Events Come Into Being: EEQT, Particle Tracks, Quantum Chaos, and Tunneling Time

In sections 1 and 2 we review Event Enhanced Quantum Theory (EEQT). In section 3 we discuss applications of EEQT to tunneling time, and compare its quantitative predictions with other approaches, in particular with B\"uttiker-Larmor and Bohm trajectory approach. In section 4 we discuss quantum chaos and quantum fractals resulting from simultaneous continuous monitoring of several non-commuting observables. In particular we show self-similar, non-linear, iterated function system-type, patterns arising from quantum jumps and from the associated Markov operator. Concluding remarks pointing to possible future development of EEQT are given in section 5.Comment: latex, 27 pages, 7 postscript figures. Paper submitted to Proc. Conference "Mysteries, Puzzles And Paradoxes In Quantum Mechanics, Workshop on Entanglement And Decoherence, Palazzo Feltrinelli, Gargnano, Garda Lake, Italy, 20-25 September, 199

Epistemic and Ontic Quantum Realities

Quantum theory has provoked intense discussions about its interpretation since its pioneer days. One of the few scientists who have been continuously engaged in this development from both physical and philosophical perspectives is Carl Friedrich von Weizsaecker. The questions he posed were and are inspiring for many, including the authors of this contribution. Weizsaecker developed Bohr's view of quantum theory as a theory of knowledge. We show that such an epistemic perspective can be consistently complemented by Einstein's ontically oriented position

A Complexity Measure for Continuous Time Quantum Algorithms

We consider unitary dynamical evolutions on n qubits caused by time dependent pair-interaction Hamiltonians and show that the running time of a parallelized two-qubit gate network simulating the evolution is given by the time integral over the chromatic index of the interaction graph. This defines a complexity measure of continuous and discrete quantum algorithms which are in exact one-to-one correspondence. Furthermore we prove a lower bound on the growth of large-scale entanglement depending on the chromatic index.Comment: 6 pages, Revte

Optimized time-dependent perturbation theory for pulse-driven quantum dynamics in atomic or molecular systems

We present a time-dependent perturbative approach adapted to the treatment of intense pulsed interactions. We show there is a freedom in choosing secular terms and use it to optimize the accuracy of the approximation. We apply this formulation to a unitary superconvergent technique and improve the accuracy by several orders of magnitude with respect to the Magnus expansion.Comment: 4 pages, 2 figure

Resonances, Unstable Systems and Irreversibility: Matter Meets Mind

The fundamental time-reversal invariance of dynamical systems can be broken in various ways. One way is based on the presence of resonances and their interactions giving rise to unstable dynamical systems, leading to well-defined time arrows. Associated with these time arrows are semigroups bearing time orientations. Usually, when time symmetry is broken, two time-oriented semigroups result, one directed toward the future and one directed toward the past. If time-reversed states and evolutions are excluded due to resonances, then the status of these states and their associated backwards-in-time oriented semigroups is open to question. One possible role for these latter states and semigroups is as an abstract representation of mental systems as opposed to material systems. The beginnings of this interpretation will be sketched.Comment: 9 pages. Presented at the CFIF Workshop on TimeAsymmetric Quantum Theory: The Theory of Resonances, 23-26 July 2003, Instituto Superior Tecnico, Lisbon, Portugal; and at the Quantum Structures Association Meeting, 7-22 July 2004, University of Denver. Accepted for publication in the Internation Journal of Theoretical Physic

Fragility of a class of highly entangled states of many quantum-bits

We consider a Quantum Computer with n quantum-bits (`qubits'), where each qubit is coupled independently to an environment affecting the state in a dephasing or depolarizing way. For mixed states we suggest a quantification for the property of showing {\it quantum} uncertainty on the macroscopic level. We illustrate in which sense a large parameter can be seen as an indicator for large entanglement and give hypersurfaces enclosing the set of separable states. Using methods of the classical theory of maximum likelihood estimation we prove that this parameter is decreasing with 1/\sqrt{n} for all those states which have been exposed to the environment. Furthermore we consider a Quantum Computer with perfect 1-qubit gates and 2-qubit gates with depolarizing error and show that any state which can be obtained from a separable initial state lies inbetween a family of pairs of certain hypersurfaces parallel to those enclosing the separable ones.Comment: 9 Pages, RevTe