452 research outputs found

    [Review of] John A. Grim. The Shaman: Patterns of Siberian and Ojibway Healing

    Get PDF
    John A. Grim utilizes the methodology of the fields of anthropology, mythology, psychology, and sociology to elucidate the religious meaning of shamanism as exemplified in Siberian and Ojibway societies. Although shamans have long been viewed as primordial religious personalities, a comprehensive interpretation of the shamanic religious experience has been lacking. This book provides important insights that will be of interest to scholars and general readers interested in the American Indian religious experience

    [Review of] Gail H. Landsman, Sovereignty and Symbol: Indian-White Conflict at Ganienkeh

    Get PDF
    Anthropologist Landsman has written a fascinating study about the events surrounding the seizure of a 612-acre abandoned girls\u27 camp in upstate New York in May 1974 by a group of Mohawks who named their settlement Ganienkeh. The ensuing Indian-white land dispute eventually culminated in the relocation of the Indians to parkland near the Canadian border in 1978 as a result of a unique arrangement, the Turtle Island Trust Agreement, which for charitable, religious and educational purposes under New York State law established a permanent, non-reservation settlement of Indians claiming sovereign status

    Transition rate of the Unruh-DeWitt detector in curved spacetime

    Full text link
    We examine the Unruh-DeWitt particle detector coupled to a scalar field in an arbitrary Hadamard state in four-dimensional curved spacetime. Using smooth switching functions to turn on and off the interaction, we obtain a regulator-free integral formula for the total excitation probability, and we show that an instantaneous transition rate can be recovered in a suitable limit. Previous results in Minkowski space are recovered as a special case. As applications, we consider an inertial detector in the Rindler vacuum and a detector at rest in a static Newtonian gravitational field. Gravitational corrections to decay rates in atomic physics laboratory experiments on the surface of the Earth are estimated to be suppressed by 42 orders of magnitude.Comment: 27 pages, 1 figure. v3: Typos corrected. Published versio

    Kaon and Φ\Phi production vs Participants in Nuclear Collisions

    Full text link
    Data on kaon and Φ\Phi production in nuclear collisions as a function of centrality are analysed both at AGS and SPS energy range. We compare the results of several experiments, looking for common trend in `participant scaling' of production yields. We find a smooth description of scaled kaon and Φ\Phi yields as a function of participant density. We also show a participant density dependence of kaons and Φ\Phi produced in the forward hemisphere for proton-nucleus collisions.Comment: Proceedings of the International Conference on Strangeness in Quark Matter, 20-25 July 2000, Berkeley, CA. To appear in Journal of Physics G: Nuclear and Particle Physic

    Gaussian Null Coordinates for Rotating Charged Black Holes and Conserved Charges

    Get PDF
    Motivated by the study of conserved Aretakis charges for a scalar field on the horizon of an extremal black hole, we construct the metrics for certain classes of four-dimensional and five-dimensional extremal rotating black holes in Gaussian null coordinates. We obtain these as expansions in powers of the radial coordinate, up to sufficient order to be able to compute the Aretakis charges. The metrics we consider are for 4-charge black holes in four-dimensional STU supergravity (including the Kerr-Newman black hole in the equal-charge case) and the general 3-charge black holes in five-dimensional STU supergravity. We also investigate the circumstances under which the Aretakis charges of an extremal black hole can be mapped by conformal inversion of the metric into Newman-Penrose charges at null infinity. We show that while this works for four-dimensional static black holes, a simple radial inversion fails in rotating cases because a necessary conformal symmetry of the massless scalar equation breaks down. We also discuss that a massless scalar field in dimensions higher than four does not have any conserved Newman-Penrose charge, even in a static asymptotically flat spacetime.Comment: 22 page

    Vacuum polarization around stars: nonlocal approximation

    Full text link
    We compute the vacuum polarization associated with quantum massless fields around stars with spherical symmetry. The nonlocal contribution to the vacuum polarization is dominant in the weak field limit, and induces quantum corrections to the exterior metric that depend on the inner structure of the star. It also violates the null energy conditions. We argue that similar results also hold in the low energy limit of quantum gravity. Previous calculations of the vacuum polarization in spherically symmetric spacetimes, based on local approximations, are not adequate for newtonian stars.Comment: 8 pages, no figure

    Then again, how often does the Unruh-DeWitt detector click if we switch it carefully?

    Get PDF
    The transition probability in first-order perturbation theory for an Unruh-DeWitt detector coupled to a massless scalar field in Minkowski space is calculated. It has been shown recently that the conventional iϵi\epsilon regularisation prescription for the correlation function leads to non-Lorentz invariant results for the transition rate, and a different regularisation, involving spatial smearing of the field, has been advocated to replace it. We show that the non-Lorentz invariance arises solely from the assumption of sudden switch-on and switch-off of the detector, and that when the model includes a smooth switching function the results from the conventional regularisation are both finite and Lorentz invariant. The sharp switching limit of the model is also discussed, as well as the falloff properties of the spectrum for large frequencies.Comment: 16 pages, v3. Final published version with section 5 expande

    What Thermodynamics tells about QCD Plasma near Phase Transition

    Get PDF
    Due to a rapid change of the entropy density s(T)s(T) across the critical temperature TcT_c of the QCD phase transition, the pressure P(T)P(T) and the energy density e(T)e(T) above TcT_c generally deviate from their Stefan-Boltzmann values. We shall demonstrate this both analytically and numerically for a general class of s(T)s(T) consistent with thermodynamical constraints and make a qualitative comparison of the result with the lattice QCD data. Quantities related to ds(T)/dTds(T)/dT such as the specific heat and sound velocity are also discussed.Comment: 6 pages revtex, 4 postscript figure

    Effects of mesonic correlations in the QCD phase transition

    Full text link
    The finite temperature phase transition of strongly interacting matter is studied within a nonlocal chiral quark model of the NJL type coupled to a Polyakov loop. In contrast to previous investigations which were restricted to the mean-field approximation, mesonic correlations are included by evaluating the quark-antiquark ring sum. For physical pion masses, we find that the pions dominate the pressure below the phase transition, whereas above T_c the pressure is well described by the mean-field approximation result. For large pion masses, as realized in lattice simulations, the meson effects are suppressed.Comment: 11 pages, 4 figures; version accepted for publication in Yad. Fiz., text extended, 1 figure adde

    Heavy Quarkonium in a weakly-coupled quark-gluon plasma below the melting temperature

    Get PDF
    We calculate the heavy quarkonium energy levels and decay widths in a quark-gluon plasma, whose temperature T and screening mass m_D satisfy the hierarchy m alpha_s >> T >> m alpha_s^2 >> m_D (m being the heavy-quark mass), at order m alpha_s^5. We first sequentially integrate out the scales m, m alpha_s and T, and, next, we carry out the calculations in the resulting effective theory using techniques of integration by regions. A collinear region is identified, which contributes at this order. We also discuss the implications of our results concerning heavy quarkonium suppression in heavy ion collisions.Comment: 25 pages, 2 figure
    corecore