8,459 research outputs found
Geodetic, teleseismic, and strong motion constraints on slip from recent southern Peru subduction zone earthquakes
We use seismic and geodetic data both jointly and separately to constrain coseismic slip from the 12 November 1996 M_w 7.7 and 23 June 2001 M_w 8.5 southern Peru subduction zone earthquakes, as well as two large aftershocks following the 2001 earthquake on 26 June and 7 July 2001. We use all available data in our inversions: GPS, interferometric synthetic aperture radar (InSAR) from the ERS-1, ERS-2, JERS, and RADARSAT-1 satellites, and seismic data from teleseismic and strong motion stations. Our two-dimensional slip models derived from only teleseismic body waves from South American subduction zone earthquakes with M_w > 7.5 do not reliably predict available geodetic data. In particular, we find significant differences in the distribution of slip for the 2001 earthquake from models that use only seismic (teleseismic and two strong motion stations) or geodetic (InSAR and GPS) data. The differences might be related to postseismic deformation or, more likely, the different sensitivities of the teleseismic and geodetic data to coseismic rupture properties. The earthquakes studied here follow the pattern of earthquake directivity along the coast of western South America, north of 5°S, earthquakes rupture to the north; south of about 12°S, directivity is southerly; and in between, earthquakes are bilateral. The predicted deformation at the Arequipa GPS station from the seismic-only slip model for the 7 July 2001 aftershock is not consistent with significant preseismic motion
Quasi-discrete microwave solitons in a split ring resonator-based left-handed coplanar waveguide
We study the propagation of quasi-discrete microwave solitons in a nonlinear
left-handed coplanar waveguide coupled with split ring resonators. By
considering the relevant transmission line analogue, we derive a nonlinear
lattice model which is studied analytically by means of a quasi-discrete
approximation. We derive a nonlinear Schr{\"o}dinger equation, and find that
the system supports bright envelope soliton solutions in a relatively wide
subinterval of the left-handed frequency band. We perform systematic numerical
simulations, in the framework of the nonlinear lattice model, to study the
propagation properties of the quasi-discrete microwave solitons. Our numerical
findings are in good agreement with the analytical predictions, and suggest
that the predicted structures are quite robust and may be observed in
experiments
Universal parametric correlations in the transmission eigenvalue spectra of disordered conductors
We study the response of the transmission eigenvalue spectrum of disordered
metallic conductors to an arbitrary external perturbation. For systems without
time-reversal symmetry we find an exact non-perturbative solution for the
two-point correlation function, which exhibits a new kind of universal behavior
characteristic of disordered conductors. Systems with orthogonal and symplectic
symmetries are studied in the hydrodynamic regime.Comment: 10 pages, written in plain TeX, Preprint OUTP-93-36S (University of
Oxford), to appear in Phys. Rev. B (Rapid Communication
A Brownian Motion Model of Parametric Correlations in Ballistic Cavities
A Brownian motion model is proposed to study parametric correlations in the
transmission eigenvalues of open ballistic cavities. We find interesting
universal properties when the eigenvalues are rescaled at the hard edge of the
spectrum. We derive a formula for the power spectrum of the fluctuations of
transport observables as a response to an external adiabatic perturbation. Our
formula correctly recovers the Lorentzian-squared behaviour obtained by
semiclassical approaches for the correlation function of conductance
fluctuations.Comment: 19 pages, written in RevTe
Manifestation of Quantum Chaos in Electronic Band Structures
We use semiconductors as an example to show that quantum chaos manifests
itself in the energy spectrum of crystals. We analyze the {\it ab initio} band
structure of silicon and the tight-binding spectrum of the alloy
, and show that some of their statistical properties obey the
universal predictions of quantum chaos derived from the theory of random
matrices. Also, the Bloch momenta are interpreted as external, tunable,
parameters, acting on the reduced (unit cell) Hamiltonian, in close analogy to
Aharonov-Bohm fluxes threading a torus. They are used in the investigation of
the parametric autocorrelator of crystal velocities. We find that our results
are in good agreement with the universal curves recently proposed by Simons and
coworkers.Comment: 15 pages with 6 Postscript figures included, RevTex-3, CMT-ERM/940
Correlations and fluctuations of a confined electron gas
The grand potential and the response of a phase-coherent confined noninteracting electron gas depend
sensitively on chemical potential or external parameter . We compute
their autocorrelation as a function of , and temperature. The result
is related to the short-time dynamics of the corresponding classical system,
implying in general the absence of a universal regime. Chaotic, diffusive and
integrable motions are investigated, and illustrated numerically. The
autocorrelation of the persistent current of a disordered mesoscopic ring is
also computed.Comment: 12 pages, 1 figure, to appear in Phys. Rev.
Exact Dynamical Correlation Functions of Calogero-Sutherland Model and One-Dimensional Fractional Statistics
One-dimensional model of non-relativistic particles with inverse-square
interaction potential known as Calogero-Sutherland Model (CSM) is shown to
possess fractional statistics. Using the theory of Jack symmetric polynomial
the exact dynamical density-density correlation function and the one-particle
Green's function (hole propagator) at any rational interaction coupling
constant are obtained and used to show clear evidences of the
fractional statistics. Motifs representing the eigenstates of the model are
also constructed and used to reveal the fractional {\it exclusion} statistics
(in the sense of Haldane's ``Generalized Pauli Exclusion Principle''). This
model is also endowed with a natural {\it exchange } statistics (1D analog of
2D braiding statistics) compatible with the {\it exclusion} statistics.
(Submitted to PRL on April 18, 1994)Comment: Revtex 11 pages, IASSNS-HEP-94/27 (April 18, 1994
An exactly solvable three-particle problem with three-body interaction
The energy spectrum of the three-particle Hamiltonian obtained by replacing
the two-body trigonometric potential of the Sutherland problem by a three-body
one of a similar form is derived. When expressed in appropriate variables, the
corresponding wave functions are shown to be expressible in terms of Jack
polynomials. The exact solvability of the problem with three-body interaction
is explained by a hidden sl(3,\R) symmetry.Comment: LaTeX, 15 pages, no figures, slightly shortened version to appear in
Phys. Rev. A, one error correcte
Multi-Locus Phylogenetic Analyses of the Almadablennius Clade Reveals Inconsistencies with the Present Taxonomy of Blenniid Fishes
We used a multi-locus phylogenetic approach (i.e., combining both mitochondrial and nuclear DNA fragments) to address some long-standing taxonomic inconsistencies within the diverse fish clade of Combtooth Blennies (Blenniidae—unranked clade Almadablennius). The obtained phylogenetic trees revealed some major inconsistencies in the current taxonomy of Parablennini, such as the paraphyletic status of the Salaria and Parablennius genera, casting some doubt regarding their actual phylogenetic relationship. Furthermore, a scarce-to-absent genetic differentiation was observed among the three species belonging to the genus Chasmodes. This study provides an updated taxonomy and phylogeny of the former genus Salaria, ascribing some species to the new genus Salariopsis gen. nov., and emphasizes the need for a revision of the genus Parablennius
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