452 research outputs found
[Review of] John A. Grim. The Shaman: Patterns of Siberian and Ojibway Healing
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
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
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 production vs Participants in Nuclear Collisions
Data on kaon and 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
yields as a function of participant density. We also show a participant
density dependence of kaons and 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
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
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?
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
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
Due to a rapid change of the entropy density across the critical
temperature of the QCD phase transition, the pressure and the
energy density above generally deviate from their Stefan-Boltzmann
values. We shall demonstrate this both analytically and numerically for a
general class of consistent with thermodynamical constraints and make a
qualitative comparison of the result with the lattice QCD data. Quantities
related to 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
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
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
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