11,267 research outputs found
Radial Anharmonic Oscillator: Perturbation Theory, New Semiclassical Expansion, Approximating Eigenfunctions. II. Quartic and Sextic Anharmonicity Cases
In our previous paper I (del Valle--Turbiner, Int. J. Mod. Phys. A34,
1950143, 2019) it was developed the formalism to study the general
-dimensional radial anharmonic oscillator with potential . It was based on the Perturbation Theory (PT) in
powers of (weak coupling regime) and in inverse, fractional powers of
(strong coupling regime) in both -space and in -space, respectively.
As the result it was introduced - the Approximant - a locally-accurate uniform
compact approximation of a wave function. If taken as a trial function in
variational calculations it has led to variational energies of unprecedented
accuracy for cubic anharmonic oscillator. In this paper the formalism is
applied to both quartic and sextic, spherically-symmetric radial anharmonic
oscillators with two term potentials ,
respectively. It is shown that a two-parametric Approximant for quartic
oscillator and a five-parametric one for sextic oscillator for the first four
eigenstates used to calculate the variational energy are accurate in 8-12
figures for any and , while the relative deviation
of the Approximant from the exact eigenfunction is less than for any
.Comment: 52 pages, 17 figures, 3 appendice
Radial power-like potentials: from the Bohr-Sommerfeld -state energies to the exact ones
Following our previous study of the Bohr-Sommerfeld (B-S) quantization
condition for one-dimensional case (del Valle \& Turbiner (2021) \cite{First}),
we extend it to -dimensional power-like radial potentials. The B-S
quantization condition for -states of the -dimensional radial
Schr\"odinger equation is proposed. Based on numerical results obtained for the
spectra of power-like potentials, with , the
correctness of the proposed B-S quantization condition is established for
various dimensions . It is demonstrated that by introducing the {\it WKB
correction} (supposedly coming from the higher order WKB terms) into
the r.h.s. of the B-S quantization condition leads to the so-called {\it exact
WKB quantization condition}, which reproduces the exact energies, while
remains always very small. For (any integer ) and for
(at ) the WKB correction : for states the B-S spectra
coincides with the exact ones.
Concrete calculations for physically important cases of linear, cubic,
quartic, and sextic oscillators, as well as Coulomb and logarithmic potentials
in dimensions are presented. Radial quartic anharmonic oscillator is
considered briefly.Comment: 15 pages, 4 figures, 4 tables; extended, some typos fixed, to be
published in IJMP
Demodulation of Spatial Carrier Images: Performance Analysis of Several Algorithms Using a Single Image
http://link.springer.com/article/10.1007%2Fs11340-013-9741-6#Optical full-field techniques have a great importance in modern experimental mechanics. Even if they are reasonably spread among the university laboratories, their diffusion in industrial companies remains very narrow for several reasons, especially a lack of metrological performance assessment. A full-field measurement can be characterized by its resolution, bias, measuring range, and by a specific quantity, the spatial resolution. The present paper proposes an original procedure to estimate in one single step the resolution, bias and spatial resolution for a given operator (decoding algorithms such as image correlation, low-pass filters, derivation tools ...). This procedure is based on the construction of a particular multi-frequential field, and a Bode diagram representation of the results. This analysis is applied to various phase demodulating algorithms suited to estimate in-plane displacements.GDR CNRS 2519 âMesures de Champs et Identification en MĂ©canique des Solide
Status of neutrino oscillations 2018: first hint for normal mass ordering and improved CP sensitivity
We present a new global fit of neutrino oscillation parameters within the
simplest three-neutrino picture, including new data which appeared since our
previous analysis~\cite{Forero:2014bxa}. In this update we include new
long-baseline neutrino data involving the antineutrino channel in T2K, as well
as new data in the neutrino channel, data from NOA, as well as new reactor
data, such as the Daya Bay 1230 days electron antineutrino disappearance
spectrum data and the 1500 live days prompt spectrum from RENO, as well as new
Double Chooz data. We also include atmospheric neutrino data from the IceCube
DeepCore and ANTARES neutrino telescopes and from Super-Kamiokande. Finally, we
also update our solar oscillation analysis by including the 2055-day day/night
spectrum from the fourth phase of the Super-Kamiokande experiment. With the new
data we find a preference for the atmospheric angle in the upper octant for
both neutrino mass orderings, with maximal mixing allowed at for normal (inverted) ordering. We also obtain a strong
preference for values of the CP phase in the range ,
excluding values close to at more than 4. More remarkably, our
global analysis shows for the first time hints in favour of the normal mass
ordering over the inverted one at more than 3. We discuss in detail the
origin of the mass ordering, CP violation and octant sensitivities, analyzing
the interplay among the different neutrino data samples.Comment: Updated neutrino oscillation analysis using the most recent results
from T2K, NOA, RENO and Super-Kamiokande. 17 pages, 8 figures, 1 tabl
A non-resonant dark-side solution to the solar neutrino problem
We re-analyse spin-flavour precession solutions to the solar neutrino problem
in the light of the recent SNO CC result as well as the 1258--day
Super-Kamiokande data and the upper limit on solar anti-neutrinos. In a
self-consistent magneto-hydrodynamics approach the resulting scheme has only 3
effective parameters: , and the neutrino mixing angle
. We show how a rates-only analysis for fixed slightly
favours spin-flavour precession (SFP) solutions over oscillations (OSC). In
addition to the resonant solution (RSFP for short), there is a new non-resonant
solution (NRSFP) in the ``dark-side''. Both RSFP and NRSFP lead to flat recoil
energy spectra in excellent agreement with the latest SuperKamiokande data. We
also show that in the presence of a neutrino transition magnetic moment of
Bohr magneton, a magnetic field of 80 KGauss eliminates all large
mixing solutions other than the so-called LMA solution.Comment: 12 pages, 3 postscript figures, using elsart.cls. Published versio
Neutrino Electron Scattering and Electroweak Gauge Structure: Future Tests
Low-energy high-resolution neutrino-electron scattering experiments may play
an important role in testing the gauge structure of the electroweak
interaction. We propose the use of radioactive neutrino sources (e.g.
Cr) in underground experiments such as BOREXINO, HELLAZ and LAMA. As an
illustration, we display the sensitivity of these detectors in testing the
possible existence of extra neutral gauge bosons, both in the framework of E_6
models and of models with left-right symmetry.Comment: 22 pages, revtex, 4 figures included, accepted for publication in
Phys. Rev.
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