17,174 research outputs found

    Comment on `Renormalization-Group Calculation of the Dependence on Gravity of the Surface Tension and Bending Rigidity of a Fluid Interface'

    Full text link
    It is shown that the interface model introduced in Phys. Rev. Lett. 86, 2369 (2001) violates fundamental symmetry requirements for vanishing gravitational acceleration gg, so that its results cannot be applied to critical properties of interfaces for g0g\to 0.Comment: A Comment on a recent Letter by J.G. Segovia-L\'opez and V. Romero-Roch\'{\i}n, Phys. Rev. Lett.86, 2369 (2001). Latex file, 1 page (revtex

    New light on the ‘Drummer of Tedworth’: conflicting narratives of witchcraft in Restoration England

    Get PDF
    This paper presents a definitive text of hitherto little-known early documents concerning ‘The Drummer of Tedworth’, a poltergeist case that occurred in 1662-3 and became famous not least due to its promotion by Joseph Glanvill in his demonological work, Saducismus Triumphatus. On the basis of these and other sources, it is shown how responses to the events at Tedworth evolved from anxious piety on the part of their victim, John Mompesson, to confident apologetic by Glanvill, before they were further affected by the emergence of articulate scepticism about the case

    Nucleon, Δ\Delta and Ω\Omega excited states in Nf=2+1N_f=2+1 lattice QCD

    Full text link
    The energies of the excited states of the Nucleon, Δ\Delta and Ω\Omega are computed in lattice QCD, using two light quarks and one strange quark on anisotropic lattices. The calculation is performed at three values of the light quark mass, corresponding to pion masses mπm_{\pi} = 392(4), 438(3) and 521(3) MeV. We employ the variational method with a large basis of interpolating operators enabling six energies in each irreducible representation of the lattice to be distinguished clearly. We compare our calculation with the low-lying experimental spectrum, with which we find reasonable agreement in the pattern of states. The need to include operators that couple to the expected multi-hadron states in the spectrum is clearly identified.Comment: Revised for publication. References added, Table VI expanded to add strange baryon multiparticle thresholds and multiparticle thresholds added to Figs. 4, 5 and 6. 15 pages, 6 figure

    Real World Interpretations of Quantum Theory

    Full text link
    I propose a new class of interpretations, {\it real world interpretations}, of the quantum theory of closed systems. These interpretations postulate a preferred factorization of Hilbert space and preferred projective measurements on one factor. They give a mathematical characterisation of the different possible worlds arising in an evolving closed quantum system, in which each possible world corresponds to a (generally mixed) evolving quantum state. In a realistic model, the states corresponding to different worlds should be expected to tend towards orthogonality as different possible quasiclassical structures emerge or as measurement-like interactions produce different classical outcomes. However, as the worlds have a precise mathematical definition, real world interpretations need no definition of quasiclassicality, measurement, or other concepts whose imprecision is problematic in other interpretational approaches. It is natural to postulate that precisely one world is chosen randomly, using the natural probability distribution, as the world realised in Nature, and that this world's mathematical characterisation is a complete description of reality.Comment: Minor revisions. To appear in Foundations of Physic

    Electrochemic properties of single-wall carbon nanotube electrodes

    Get PDF
    The electrochemical properties of single-wall carbon nanotube ~CNT! electrodes in the form of sheets or papers have been examined. Thermal annealing has produced significant changes in a range of properties of the material including increased hydrophobicity and elimination of electroactive surface functional groups and other impurities. As a result of these changes, the treated electrodes exhibit lower double-layer capacitance, absence of faradaic responses and associated pseudocapacitance, and a better frequency response. The basic electrochemical behavior of the CNT paper electrodes is not markedly affected by relatively large differences in electrolyte ion size, consistent with an average pore size of 9 nm. Increases in both CNT sheet thickness and surface area induce a slower electrode response in agreement with the porous nature of the electrode matrix

    Interface relaxation in electrophoretic deposition of polymer chains: Effects of segmental dynamics, molecular weight, and field

    Get PDF
    Using different segmental dynamics and relaxation, characteristics of the interface growth is examined in an electrophoretic deposition of polymer chains on a three (2+1) dimensional discrete lattice with a Monte Carlo simulation. Incorporation of faster modes such as crankshaft and reptation movements along with the relatively slow kink-jump dynamics seems crucial in relaxing the interface width. As the continuously released polymer chains are driven (via segmental movements) and deposited, the interface width WW grows with the number of time steps tt, Wtβ,W \propto t^{\beta}, (β0.4\beta \sim 0.4--0.8)0.8), which is followed by its saturation to a steady-state value WsW_s. Stopping the release of additional chains after saturation while continuing the segmental movements relaxes the saturated width to an equilibrium value (WsWrW_s \to W_r). Scaling of the relaxed interface width WrW_r with the driving field EE, WrE1/2W_r \propto E^{-1/2} remains similar to that of the steady-state WsW_s width. In contrast to monotonic increase of the steady-state width WsW_s, the relaxed interface width WrW_r is found to decay (possibly as a stretched exponential) with the molecular weight.Comment: 5 pages, 7 figure

    Nitrous oxide water column distribution during the transition from anoxic to oxic conditions in the Baltic Sea

    No full text
    International audienceIn January 2003, a major inflow of cold and oxygen-rich North Sea Water in the Baltic Sea terminated an ongoing stagnation period in parts of the central Baltic Sea. In order to investigate the role of North Sea Water inflow to the Baltic Sea with regard to the production of nitrous oxide (N2O), we measured dissolved and atmospheric N2O at 26 stations in the southern and central Baltic Sea in October 2003. At the time of our cruise, water renewal had proceeded to the eastern Gotland Basin, whereas the western Gotland Basin was still unaffected by the inflow. The deep water renewal was detectable in the distributions of temperature, salinity, and oxygen concentrations as well as in the distribution of the N2O concentrations: Shallow stations in the Kiel Bight and Pomeranian Bight were well-ventilated with uniform N2O concentrations near equilibrium throughout the water column. In contrast, stations in the deep basins, such as the Bornholm and the Gotland Deep, showed a clear stratification with deep water affected by North Sea Water. Inflowing North Sea Water led to changed environmental conditions, especially enhanced oxygen (O2) or declining hydrogen sulfide (H2S) concentrations, thus, affecting the conditions for the production of N2O. Pattern of N2O profiles and correlations with parameters like oxygen and nitrate differed between the basins. The dominant production pathway seems to be nitrification rather than denitrification. No indications for advection of N2O by North Sea Water were found. A rough budget revealed a significant surplus of in situ produced N2O after the inflow. However, due to the permanent halocline, it can be assumed that the formed N2O does not reach the atmosphere. Hydrographic aspects therefore are decisive factors determining the final release of produced N2O to the atmosphere

    Strong electron-phonon coupling in delta-phase stabilized Pu

    Full text link
    Heat capacity measurements of the delta-phase stabilized alloy Pu-Al suggest that strong electron-phonon coupling is required to explain the moderate renormalization of the electronic density of states near the Fermi energy. We calculate the heat capacity contributions from the lattice and electronic degrees of freedom as well as from the electron-lattice coupling term and find good overall agreement between experiment and theory assuming a dimensionless electron-phonon coupling parameter of order unity, lambda ~ 0.8. This large electron-phonon coupling parameter is comparable to reported values in other superconducting metals with face-centered cubic crystal structure, for example, Pd (lambda ~ 0.7) and Pb (lambda ~ 1.5). Further, our analysis shows evidence of a sizable residual low-temperature entropy contribution, S_{res} ~ 0.4 k_B (per atom). We can fit the residual specific heat to a two-level system. Therefore, we speculate that the observed residual entropy originates from crystal-electric field effects of the Pu atoms or from self-irradiation induced defects frozen in at low temperatures.Comment: 9 pages, 11 figures, to appear in Phys. Rev.

    Relativistic three-particle scattering equations

    Get PDF
    We derive a set of relativistic three-particle scattering equations in the three-particle c.m. frame employing a relativistic three-particle propagator suggested long ago by Ahmadzadeh and Tjon in the c.m. frame of a two-particle subsystem. We make the coordinate transformation of this propagator from the c.m. frame of the two-particle subsystem to the three-particle c.m. frame. We also point out that some numerical applications of the Ahmadzadeh and Tjon propagator to the three-nucleon problem use unnecessary nonrelativistic approximations which do not simplify the computational task, but violate constraints of relativistic unitarity and/or covariance.Comment: 5pages, text and one ps figure (in revtex) include
    corecore