1,859 research outputs found
Neutrino quasinormal modes of the Reissner-Nordstr\"om black hole
The neutrino quasinormal modes of the Reissner-Nordstr\"om (RN) black hole
are investigated using continued fraction approach. We find, for large angular
quantum number, that the quasinormal frequencies become evenly spaced and the
spacing of the real part depends on the charge of the black hole and that of
the imaginary part is zero. We then find that the quasinormal frequencies in
the complex plane move counterclockwise as the charge increases. They
get a spiral-like shape, moving out of their Schwarzschild value and ``looping
in" towards some limiting frequency as the charge tends to the extremal value.
The number of the spirals increases as the overtone number increases but it
decreases as the angular quantum number increases. We also find that both the
real and imaginary parts are oscillatory functions of the charge, and the
oscillation becomes faster as the overtone number increases but it becomes
slower as the angular quantum number increases.Comment: 11 pages, 3 figure
An efficient compressive sensing based PS-DInSAR method for surface deformation estimation
Permanent scatterers differential interferometric synthetic aperture radar (PS-DInSAR) is a
technique for detecting surface micro-deformation, with an accuracy at the centimeter to millimeter
level. However, its performance is limited by the number of SAR images available (normally more than
20 are needed). Compressive Sensing (CS) has been proven to be an effective signal recovery method
with only a very limited number of measurements. Applying CS to PS-DInSAR, a novel
CS-PS-DInSAR method is proposed to estimate the deformation with fewer SAR images. By analyzing
the PS-DInSAR process in detail, first the sparsity representation of deformation velocity difference is
obtained; then, the mathematical model of CS-PS-DInSAR is derived and the restricted isometry
property (RIP) of the measurement matrix is discussed to validate the proposed CS-PS-DInSAR in
theory. The implementation of CS-PS-DInSAR is achieved by employing basis pursuit algorithms to
estimate the deformation velocity. With the proposed method, DInSAR deformation estimation can be
achieved by a much smaller number of SAR images, as demonstrated by simulation result
Separability of Hamilton-Jacobi and Klein-Gordon Equations in General Kerr-NUT-AdS Spacetimes
We demonstrate the separability of the Hamilton-Jacobi and scalar field
equations in general higher dimensional Kerr-NUT-AdS spacetimes. No restriction
on the parameters characterizing these metrics is imposed.Comment: 4 pages, no figure
PHP61 The Financial Impacts of Pharmacist Intervention in Inpatient Department of a Local Hospital in Taiwan
Morphometric analysis of S. mortenseni. (DOC 44Â kb
Charge Exchange Cross Sections in Collisions of Highly Charged Argon Ions with Helium, Neon, and Argon Atoms
Exactly solvable model of quantum diffusion
We study the transport property of diffusion in a finite translationally
invariant quantum subsystem described by a tight-binding Hamiltonian with a
single energy band and interacting with its environment by a coupling in terms
of correlation functions which are delta-correlated in space and time. For weak
coupling, the time evolution of the subsystem density matrix is ruled by a
quantum master equation of Lindblad type. Thanks to the invariance under
spatial translations, we can apply the Bloch theorem to the subsystem density
matrix and exactly diagonalize the time evolution superoperator to obtain the
complete spectrum of its eigenvalues, which fully describe the relaxation to
equilibrium. Above a critical coupling which is inversely proportional to the
size of the subsystem, the spectrum at given wavenumber contains an isolated
eigenvalue describing diffusion. The other eigenvalues rule the decay of the
populations and quantum coherences with decay rates which are proportional to
the intensity of the environmental noise. On the other hand, an analytical
expression is obtained for the dispersion relation of diffusion. The diffusion
coefficient is proportional to the square of the width of the energy band and
inversely proportional to the intensity of the environmental noise because
diffusion results from the perturbation of quantum tunneling by the
environmental fluctuations in this model. Diffusion disappears below the
critical coupling.Comment: Submitted to J. Stat. Phy
On the Observability of "Invisible" / "Nearly Invisible" Charginos
It is shown that if the charginos decay into very soft leptons or hadrons +
due to degeneracy/ near- degeneracy with the LSP or the sneutrino,
the observability of the recently proposed signal via the single photon (+ soft
particles) + channel crucially depends on the magnitude of the \SNU
mass due to destructive interferences in the matrix element squared. If the
\SNU's and, consequently, left-sleptons are relatively light, the size of the
signal, previously computed in the limit \MSNU \to \infty only, is
drastically reduced. We present the formula for the signal cross section in a
model independent way and discuss the observability of the signal at LEP 192
and NLC energies.Comment: 27 pages, Late
On -transforms of one-dimensional diffusions stopped upon hitting zero
For a one-dimensional diffusion on an interval for which 0 is the
regular-reflecting left boundary, three kinds of conditionings to avoid zero
are studied. The limit processes are -transforms of the process stopped
upon hitting zero, where 's are the ground state, the scale function, and
the renormalized zero-resolvent. Several properties of the -transforms are
investigated
Quasi-normal modes of warped black holes and warped AdS/CFT correspondence
We analytically calculate the quasi-normal modes of various perturbations of
spacelike stretched and null warped black holes. From AdS/CFT
correspondence, these quasi-normal modes are expected to appear as the poles in
momentum space of retarded Green functions of dual operators in CFT at finite
temperature. We find that this is indeed the case, after taking into account of
the subtle identification of quantum numbers. The subtlety comes from the fact
that only after appropriate coordinate transformation the asymptotic geometries
of warped black holes are the same as the ones of warped spacetimes. We
show that in general the quasi-normal modes are in good agreement with the
prediction of the warped AdS/CFT correspondence, up to a constant factor. As a
byproduct, we compute the conformal dimensions of boundary operators dual to
the perturbations. Our result gives strong support to the conjectured warped
AdS/CFT correspondence.Comment: 26 pages; typos corrected, references added; more clarifications,
match the version to appear in JHE
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