1,326 research outputs found
Dual description of U(1) charged fields in (2+1) dimensions
We show that the functional bosonization procedure can be generalized in such
a way that, to any field theory with a conserved Abelian charge in (2+1)
dimensions, there corresponds a dual Abelian gauge field theory. The properties
of this mapping and of the dual theory are discussed in detail, presenting
different explicit examples. In particular, the meaning and effect of the
coefficient of the Chern-Simons term in the dual action is interpreted in terms
of the spin and statistics connection.Comment: 25 page
A High Resolution Method for Measuring Cosmic Ray Composition beyond 10 TeV
The accurate determination of the elemental composition of cosmic rays at
high energies is expected to provide crucial clues on the origin of these
particles. Previous direct measurements of composition have been limited by
experiment collecting power, resulting in marginal statistics above
eV, precisely the region where the ``knee'' of the cosmic-ray energy spectrum
is starting to develop. In contrast, indirect measurements using extensive air
showers can produce sufficient statistics in this region but generate elemental
measurements which have relatively large uncertainties. Here we discuss a
technique which has become possible through the use of modern ground-based
Cerenkov imaging detectors. We combine a measurement of the Cerenkov light
produced by the incoming cosmic-ray nucleus in the upper atmosphere with an
estimate of the total nucleus energy produced by the extensive air shower
initiated when the particle interacts deeper in the atmosphere. The emission
regions prior to and after the first hadronic interaction can be separated by
an imaging Cerenkov system with sufficient angular and temporal resolution.
Monte Carlo simulations indicate an expected charge resolution of for incident iron nuclei in the region of the ``knee'' of the cosmic-ray
energy spectrum. This technique also has the intriguing possibility to
unambiguously discover nuclei heavier than iron at energies above 10 eV.
The identification and rejection of background produced by charged particles in
ground based gamma-ray telescopes is also discussed.Comment: 26 pages 11 figures. Final version, Accepted in Astroparticle Physics
11/21/00. Fixed a few typos and a bad caption, added a short paragraph at en
Three dimensional fermionic determinants, Chern-Simons and nonlinear field redefinitions
The three dimensional abelian fermionic determinant of a two component
massive spinor in flat euclidean space-time is resetted to a pure Chern-Simons
action through a nonlinear redefinition of the gauge field.Comment: 18 pages, latex2
Black Hole Entropy: From Shannon to Bekenstein
In this note we have applied directly the Shannon formula for information
theory entropy to derive the Black Hole (Bekenstein-Hawking) entropy. Our
analysis is semi-classical in nature since we use the (recently proposed [8])
quantum mechanical near horizon mode functions to compute the tunneling
probability that goes in to the Shannon formula, following the general idea of
[5]. Our framework conforms to the information theoretic origin of Black Hole
entropy, as originally proposed by Bekenstein.Comment: 9 pages Latex, Comments are welcome; Thoroughly revised version,
reference and acknowledgements sections enlarged, numerical error in final
result corrected, no major changes, to appear in IJT
Peak effect at microwave frequencies in swift heavy ion irradiated YBa2Cu3O7âÎŽ thin films
The vortex dynamics at microwave frequencies in YBa2Cu3O7âÎŽ (YBCO) films have been studied. We observe a peak in the microwave (4.88 and 9.55 GHz) surface resistance in some films in magnetic fields up to 0.8 T. This is associated with the âpeak-effectâ phenomenon and reflects the orderâdisorder transformation of the flux line lattice near the transition temperature. Introduction of artificial pinning centers like columnar defects created as a result of irradiation with 200 MeV Ag ion (at a fluence of 4 Ă 10^10 ions/cm2) leads to the suppression of the peak in films previously exhibiting âpeak effectâ
Higher order WKB corrections to black hole entropy in brick wall formalism
We calculate the statistical entropy of a quantum field with an arbitrary
spin propagating on the spherical symmetric black hole background by using the
brick wall formalism at higher orders in the WKB approximation. For general
spins, we find that the correction to the standard Bekenstein-Hawking entropy
depends logarithmically on the area of the horizon. Furthermore, we apply this
analysis to the Schwarzschild and Schwarzschild-AdS black holes and discuss our
results.Comment: 21 pages, published versio
A Farey tale for N=4 dyons
We study exponentially suppressed contributions to the degeneracies of
extremal black holes. Within Sen's quantum entropy function framework and
focusing on extremal black holes with an intermediate AdS3 region, we identify
an infinite family of semi-classical AdS2 geometries which can contribute
effects of order exp(S_0/c), where S_0 is the Bekenstein-Hawking-Wald entropy
and c is an integer greater than one. These solutions lift to the extremal
limit of the SL(2,Z) family of BTZ black holes familiar from the "black hole
Farey tail". We test this understanding in N=4 string vacua, where exact dyon
degeneracies are known to be given by Fourier coefficients of Siegel modular
forms. We relate the sum over poles in the Siegel upper half plane to the Farey
tail expansion, and derive a "Farey tale" expansion for the dyon partition
function. Mathematically, this provides a (formal) lift from Hilbert modular
forms to Siegel modular forms with a pole at the diagonal divisor.Comment: 31 page
- âŠ