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Quantum Theory (quantum + theory)
Selected AbstractsResponse to Tune on Hume, Quantum Theory, and ResurrectionDIALOG, Issue 4 2004Kirk Wegter-McNelly No abstract is available for this article. [source] Quantum Theory and the Resurrection of JesusDIALOG, Issue 3 2004By Anders S. Tune Abstract:, Ever since the time of Hume it has been a truism that the worldview of empirical science, and Christian assertion of the resurrection of Jesus, are antithetical to each other. Yet post-Newtonian science, and especially quantum theory, suggests the need for a reappraisal of this truism. This reappraisal will first examine the implications of the indeterminism of the quantum world, to consider the physical possibility of Jesus' resurrection. Second, an appraisal of the historical evidence will suggest the likelihood of Jesus' resurrection. Finally, I will consider some implications of all this for contemporary Christian thought. [source] Weak intra- and intermolecular interactions in a binaphthol imine: an experimental charge-density study on (±)-8,-benzhydrylideneamino-1,1,-binaphthyl-2-olACTA CRYSTALLOGRAPHICA SECTION B, Issue 6 2009Louis J. Farrugia The charge density in (±)-8,-benzhydrylideneamino-1,1,-binaphthyl-2-ol (1) has been studied experimentally using Mo,K, X-ray diffraction at 100,K, and by theory using density-functional thoery (DFT) calculations at the B3LYP/6-311++G** level. The nature of the weak intramolecular peri -C...N, CH...,, H...H and C(,)...C(,) interactions has been examined by topological analysis using the Quantum Theory of Atoms in Molecules (QTAIM) approach. An analysis of the density ,(r), the Laplacian of the density ,2,(rb) and other topological properties at the bond-critical points were used to classify these interactions. The study confirms the presence of the intramolecular CH..., interaction in (1), which was previously suspected on geometrical grounds. An analysis of the ellipticity profiles along the bond paths unambiguously shows the ,-delocalization between the imine unit and one N -phenyl group. The weak intermolecular interactions in the crystal of (1) were examined experimentally and theoretically through the pairwise interactions of the seven independent dimeric pairs of (1) responsible for the set of unique intermolecular interactions, and also through examination of the Hirshfeld surface dnorm property. The theoretical dimeric-pair calculations used the BLYP-D functional which supplements the exchange-correlational functional with an empirical dispersion term to provide a more accurate determination of the energies for the weak intermolecular interactions. [source] Modern nursing and modern physics: does quantum theory contain useful insights for nursing practice and healthcare management?NURSING PHILOSOPHY, Issue 3 2002John Hastings MBA BSc (Physics) RGN RNT DMS Abstract In recent years, a number of articles have appeared in the nursing literature proposing that the branch of modern physics known as quantum theory offers insights that may be useful in nursing practice and healthcare management. This paper critiques this literature in the light of key concepts in quantum theory. The conclusion is that quantum theory has been misunderstood and misapplied within the nursing journals. Quantum theory is essentially mathematical and is based on quantitative experimentation. To successfully apply this theory to nursing practice, nurses will have to equip themselves with the necessary mathematical and experimental skills. [source] Quantum Theory and the Resurrection of JesusDIALOG, Issue 3 2004By Anders S. Tune Abstract:, Ever since the time of Hume it has been a truism that the worldview of empirical science, and Christian assertion of the resurrection of Jesus, are antithetical to each other. Yet post-Newtonian science, and especially quantum theory, suggests the need for a reappraisal of this truism. This reappraisal will first examine the implications of the indeterminism of the quantum world, to consider the physical possibility of Jesus' resurrection. Second, an appraisal of the historical evidence will suggest the likelihood of Jesus' resurrection. Finally, I will consider some implications of all this for contemporary Christian thought. [source] Time asymmetric quantum theory , I. Modifying an axiom of quantum physicsFORTSCHRITTE DER PHYSIK/PROGRESS OF PHYSICS, Issue 6 2003A.R. Bohm A slight modification of one axiom of quantum theory changes a reversible theory into a time asymmetric theory. Whereas the standard Hilbert space axiom does not distinguish mathematically between the space of states (in-states of scattering theory) and the space of observables (out-"states" of scattering theory) the new axiom associates states and observables to two different Hardy subspaces which are dense in the same Hilbert space and analytic in the lower and upper complex energy plane, respectively. As a consequence of this new axiom the dynamical equations (Schrödinger or Heisenberg) integrate to a semigroup evolution. Extending this new Hardy space axiom to a relativistic theory provides a relativistic theory of resonance scattering and decay with Born probablilities that fulfill Einstein causality and the exponential decay law. [source] Time asymmetric quantum theory , II.FORTSCHRITTE DER PHYSIK/PROGRESS OF PHYSICS, Issue 6 2003Relativistic resonances from S -matrix poles Abstract Relativistic resonances and decaying states are described by representations of Poincaré transformations, similar to Wigner's definition of stable particles. To associate decaying state vectors to resonance poles of the S -matrix, the conventional Hilbert space assumption (or asymptotic completeness) is replaced by a new hypothesis that associates different dense Hardy subspaces to the in- and out-scattering states. Then one can separate the scattering amplitude into a background amplitude and one or several "relativistic Breit-Wigner" amplitudes, which represent the resonances per se. These Breit-Wigner amplitudes have a precisely defined lineshape and are associated to exponentially decaying Gamow vectors which furnish the irreducible representation spaces of causal Poincaré transformations into the forward light cone. [source] Time asymmetric quantum theory , III.FORTSCHRITTE DER PHYSIK/PROGRESS OF PHYSICS, Issue 6 2003Decaying states, the causal Poincaré semigroup Abstract These Gamow kets span an irreducible representation space for Poincaré transformations which, similar to the Wigner representations for stable particles, are characterized by spin (angular momentum of the partial wave amplitude) and complex mass (position of the resonance pole). The Poincaré transformations of the Gamow kets, as well as of the Lippmann-Schwinger plane wave scattering states, form only a semigroup of Poincaré transformations into the forward light cone. Their transformation properties are derived. From these one obtains an unambiguous definition of resonance mass and width for relativistic resonances. The physical interpretation of these transformations for the Born probabilities and the problem of causality in relativistic quantum physics is discussed. [source] Multiphoton entanglement and interferometryFORTSCHRITTE DER PHYSIK/PROGRESS OF PHYSICS, Issue 4-5 2003M. Bourennane Multiphoton entanglement is the basis of many quantum communication schemes, quantum cryptographic protocols, and fundamental tests of quantum theory. Spontaneous parametric down-conversion is the most effective source for polarization entangled photon pairs. Here we show, that a class of entangled 4-photon states can be directly created by parametric down-conversion. These states exhibit perfect quantum correlations and a high robustness of entanglement against photon loss. Therefore these states are well suited for new types of quantum communication. [source] High-frequency transmission through metallic single-walled carbon nanotube interconnectsINTERNATIONAL JOURNAL OF NUMERICAL MODELLING: ELECTRONIC NETWORKS, DEVICES AND FIELDS, Issue 5 2009M. S. Tahvili Abstract In this paper, high-frequency transmission behavior of metallic single-walled carbon nanotube (SWCNT) interconnects is investigated. The SWCNT is assumed to be lying over a doped Si substrate, in a transmission line configuration. A hybrid approach, combining quantum theory with classical distributed-element model is utilized to predict dynamical performance of the metallic SWCNT as a nano transmission line. Several aspects of high-frequency performance of such interconnect, including the effect of SWCNT length and substrate doping level, is studied. A novel modification is proposed to take damping mechanisms effect caused by the imperfect conductance of substrate into account. The results show that the impact of limited conductivity of the substrate determines the dynamical behavior of short SWCNTs; whereas in case of long nanotubes, damping effects that arise from scattering mechanisms are dominant. Copyright © 2009 John Wiley & Sons, Ltd. [source] Hydrogen bonds assisted by ,-electron delocalization , the influence of external intermolecular interactions on dimer of formic acidJOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 7-8 2008awomir J. Grabowski Abstract MP2 and DFT calculations with the use of 6-311++G(d,p) basis set were carried out to study formic acid dimer as well as this species interacting with additional Lewis acids such as HF, Li+ and Na+. These Lewis acids were positioned near carbonyl or hydroxyl oxygen atoms and their influence on geometrical and other parameters of formic acid dimer was analysed. Additionally the ,quantum theory of atoms in molecules' (QTAIM) was applied as well as the ,natural bond orbitals' (NBO) method. Numerous correlations between geometrical, QTAIM and energetic parameters were found. It was found that ,-electron delocalization is not always connected with the enhancement of H-bond strength. Copyright © 2008 John Wiley & Sons, Ltd. [source] Modern nursing and modern physics: does quantum theory contain useful insights for nursing practice and healthcare management?NURSING PHILOSOPHY, Issue 3 2002John Hastings MBA BSc (Physics) RGN RNT DMS Abstract In recent years, a number of articles have appeared in the nursing literature proposing that the branch of modern physics known as quantum theory offers insights that may be useful in nursing practice and healthcare management. This paper critiques this literature in the light of key concepts in quantum theory. The conclusion is that quantum theory has been misunderstood and misapplied within the nursing journals. Quantum theory is essentially mathematical and is based on quantitative experimentation. To successfully apply this theory to nursing practice, nurses will have to equip themselves with the necessary mathematical and experimental skills. [source] Polariton entanglement in the self-stimulated regimePHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2006S. Portolan Abstract We investigate the influence of environmental noise on polariton entangled pairs in the self-stimulated regime. By adopting a recent separability criterion, we show that self-stimulation may suppress the detrimental influence of noise on entanglement, but once effective, a noise-equipped classical model of parametric emission provides the same results of quantum theory with respect to the separability criterion. More generally we show that, in the macroscopic limit, it is not possible to observe violations of local realism with measurements of finite order n -particle correlations only. These results provide a prototypical case of the emergence of macroscopic local realism in the presence of strong entanglement even in the absence of decoherence. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Validation of experimental charge densities: refinement of the macrolide antibiotic roxithromycinACTA CRYSTALLOGRAPHICA SECTION B, Issue 5 2010J. J. Holstein Multipole refinements of larger organic molecules have so far been limited to a few exceptional cases. We report an investigation of the detailed experimental electron-density distribution (EDD) of roxithromycin, a macrolide antibiotic consisting of 134 atoms. Although the experimental multipole refinement on high-resolution synchrotron data converged smoothly, validation of the electron density by calculation of an `experiment minus invariom' difference density revealed conformational disorder of the H atoms. Hydrogen disorder is shown to affect the EDD, the electrostatic potential and atomic properties as defined by Bader's quantum theory of atoms in molecules. A procedure to obtain the electron density distribution in the presence of disorder is proposed. [source] The experimental and theoretical QTAIMC study of the atomic and molecular interactions in dinitrogen tetroxideACTA CRYSTALLOGRAPHICA SECTION B, Issue 5 2009Vladimir G. Tsirelson The atomic and molecular interactions in a crystal of dinitrogen tetraoxide, ,-N2O4, have been studied in terms of the quantum topological theory of molecular structure using high-resolution, low-temperature X-ray diffraction data. The experimental electron density and electrostatic potential have been reconstructed with the Hansen,Coppens multipole model. In addition, the three-dimensional periodic electron density of crystalline ,-N2O4 has been calculated at the B3LYP/cc-pVDZ level of theory with and without the geometry optimization. The application of the quantum theory of atoms in molecules and crystals (QTAIMC) recovered the two types of intermolecular bond paths between O atoms in crystalline ,-N2O4, one measuring 3.094, the other 3.116,Å. The three-dimensional distribution of the Laplacian of the electron density around the O atoms showed that the lumps in the negative Laplacian fit the holes on the O atoms in the adjacent molecules, both atoms being linked by the intermolecular bond paths. This shows that the Lewis-type molecular complementarity contributes significantly to intermolecular bonding in crystalline N2O4. Partial overlap of atomic-like basins created by zero-flux surfaces in both the electron density and the electrostatic potential show that attractive electrostatic interaction exists between O atoms even though they carry the same net formal charge. The exchange and correlation contributions to the potential energy density were also computed by means of the model functionals, which use the experimental electron density and its derivatives. It was found that the intermolecular interactions in ,-N2O4 are accompanied by the correlation energy-density `bridges' lowering the local potential energy along the intermolecular O...O bond paths in the electron density, while the exchange energy density governs the shape of bounded molecules. [source] A new look at the quantum mechanics of the harmonic oscillatorANNALEN DER PHYSIK, Issue 7-8 2007H.A. Kastrup Abstract In classical mechanics the harmonic oscillator (HO) provides the generic example for the use of angle and action variables and I > 0 which played a prominent role in the "old" Bohr-Sommerfeld quantum theory. However, already classically there is a problem which has essential implications for the quantum mechanics of the (,,I)-model for the HO: the transformation is only locally symplectic and singular for (q,p) = (0,0). Globally the phase space {(q,p)} has the topological structure of the plane ,2, whereas the phase space {(,,I)} corresponds globally to the punctured plane ,2 -(0,0) or to a simple cone with the tip deleted. From the properties of the symplectic transformations on that phase space one can derive the functions h0 = I, h1 = Icos , and h2 = - Isin , as the basic coordinates on {(,,I)}, where their Poisson brackets obey the Lie algebra of the symplectic group of the plane. This implies a qualitative difference as to the quantum theory of the phase space {(,,I)} compared to the usual one for {(q,p)}: In the quantum mechanics for the (,,I)-model of the HO the three hj correspond to the self-adjoint generators Kj, j = 0,1,2, of certain irreducible unitary representations of the symplectic group or one of its infinitely many covering groups, the representations being parametrized by a (Bargmann) index k > 0. This index k determines the ground state energy of the (,,I)-Hamiltonian . For an m -fold covering the lowest possible value for k is k = 1/m, which can be made arbitrarily small by choosing m accordingly! This is not in contradiction to the usual approach in terms of the operators Q and P which are now expressed as functions of the Kj, but keep their usual properties. The richer structure of the Kj quantum model of the HO is "erased" when passing to the simpler (Q,P)-model! This more refined approach to the quantum theory of the HO implies many experimental tests: Mulliken-type experiments for isotopic diatomic molecules, experiments with harmonic traps for atoms, ions and BE-condensates, with charged HOs in external electric fields and the (Landau) levels of charged particles in external magnetic fields, with the propagation of light in vacuum, passing through strong external electric or magnetic fields. Finally it may lead to a new theoretical estimate for the quantum vacuum energy of fields and its relation to the cosmological constant. [source] Electronic Properties of 3,3,-Dimethyl-5,5,-bis(1,2,4-triazine): Towards Design of Supramolecular Arrangements of N-Heterocyclic CuI ComplexesCHEMISTRY - A EUROPEAN JOURNAL, Issue 12 2007Blandine Courcot Dr. Abstract A new efficient and safe synthesis of 3,3,-dimethyl-5,5,-bis-(1,2,4-triazine) is presented. The electron-density distribution and electrostatic properties (charge, electrostatic potential) of this molecule were analyzed. These properties were derived from a high-resolution single-crystal X-ray diffraction experiment at 100,K and compared to the results obtained from ab initio DFT quantum-mechanical calculations. Comparisons of its electrostatic potential features and integrated atomic charges (quantum theory of atoms in molecules, QTAIM) have been made with those of related molecules such as bipyrimidine ligands. Two methods were used to derive integrated charges: one is based on the conventional analytical procedure and the second uses a steepest-ascent numerical algorithm. Excellent agreement was obtained between these two methods. Charges and electrostatic potential were used as predictive indices of metal chelation and discussed in the light of complexation abilities of the title compound and related molecules. The crystal structure of a CuI complex of 3,3,-dimethyl-5,5,-bis(1,2,4-triazine) is reported here. In the solid state, this complex forms a three-dimensional multibranch network with open channels in which counterions and solvent molecules are located. This architecture involves both cis and trans isomers of the title compound. [source] | |||||||||||||