Elastic Resonance Research Articles

The non-ordinary Regge behavior of the K^*_0(800) or kappa -meson versus the ordinary K^*_0(1430)

The Regge trajectory of an elastic resonance can be calculated from dispersion theory, instead of fitted phenomenologically, using only its pole parameters as input. This also provides a correct treatment of resonance widths in Regge trajectories, essential for very wide resonances. In this work we first calculate the K^*_0(1430) Regge trajectory, finding the ordinary almost real and linear behavior, typical of q bar{q} resonances. In contrast, for the K^*_0(800) meson, the resulting Regge trajectory is non-linear and has a much smaller slope than ordinary resonances, being remarkably similar to that of the f_0(500) or sigma meson. The slope of these unusual Regge trajectories seems to scale with the meson masses rather than with scales typical of quark degrees of freedom. We also calculate the range of the interaction responsible for the formation of these resonances. Our results strongly support a non-ordinary, predominantly meson–meson-like, interpretation for the lightest strange and non-strange resonances.

Formation and stimulated photodissociation of metastable molecules with emission of photon at the collision of two atoms in a laser radiation field

The formation of metastable molecules (Feshbach resonances) at the collision of two atoms and subsequent stimulated transition to a lower unbound electronic molecular state, with emission of a photon of the laser radiation has been investigated. This can develop, in particular, for Rb2 molecules due to resonance scattering of two Rb atoms. This process is a basis for the creation of excimer lasers. Expressions have been obtained for the cross sections of elastic and inelastic resonance scattering and the intensity of the stimulated emission of the photons.

Porogranular materials composed of elastic Helmholtz resonators for acoustic wave absorption.

A theoretical and experimental study of the acoustic absorption of granular porous media made of non-cohesive piles of spherical shells is presented. These shells are either rigid or elastic, possibly drilled with a neck (Helmholtz resonators), and either porous or impervious. A description is given of acoustic propagation through these media using the effective medium models proposed by Johnson (rigid particles) and Boutin (rigid Helmholtz resonators), which are extended to the configurations studied in this work. A solution is given for the local equation of elasticity of a shell coupled to the viscous flow of air through the neck and the micropores. The models and the simulations are compared to absorption spectra measured in reflection in an impedance tube. The effective medium models and the measurements show excellent agreement for configurations made of rigid particles and rigid Helmholtz resonators that induce an additional peak of absorption at low frequency. A shift of the Helmholtz resonance toward low frequencies, due to the softness of the shells is revealed by the experiments for elastic shells made of soft elastomer and is well reproduced by the simulations. It is shown that microporous shells enhance and broaden acoustic absorption compared to stiff or elastic resonators.

Bsπ+ scattering and search for X(5568) with lattice QCD

We investigate $B_s\pi^+$ scattering in s-wave using lattice QCD in order to search for an exotic resonance X(5568) with flavor $\bar b s \bar d u$; such a state was recently reported by D0 but was not seen by LHCb. If X(5568) with $J^P=0^+$ exists, it can strongly decay only to $B_s\pi^+$ and lies significantly below all other thresholds, which makes a lattice search for X(5568) cleaner and simpler than for other exotic candidates. Both an elastic resonance in $B_s\pi^+$ as well as a deeply bound $B^+\bar K^0$ would lead to distinct signatures in the energies of lattice eigenstates, which are not seen in our simulation. We therefore do not find a candidate for X(5568) with $J^P=0^+$ in agreement with the recent LHCb result. The extracted $B_s\pi^+$ scattering length is compatible with zero within the error.

Excitation of hypersound by multiplication of the ferromagnetic resonance frequency in a magnetostriction transducer

With reference to the problem of increasing the frequency of hypersound excited by a magnetostriction transducer, the feasibility of multiplication of the frequency by multiplication of the eigenfrequency of the elastic resonator is considered. It is shown that efficient multiplication is possible only in odd harmonics of the excitation signal. For interpretation of the phenomenon observed, a model of nonlinear excitation due to multiplication of the values of the longitudinal and transverse magnetization components is proposed.

Pore space characterization in carbonate rocks — Approach to combine nuclear magnetic resonance and elastic wave velocity measurements

Pore space features influence petrophysical parameters such as porosity, permeability, elastic wave velocity or nuclear magnetic resonance (NMR). Therefore they are essential to describe the spatial distribution of petrophysical parameters in the subsurface, which is crucial for efficient reservoir characterization especially in carbonate rocks. While elastic wave velocity measurements respond to the properties of the solid rock matrix including pores or fractures, NMR measurements are sensitive to the distribution of pore-filling fluids controlled by rock properties such as the pore-surface-to-pore-volume ratio. Therefore a combination of both measurement principles helps to investigate carbonate pore space using complementary information.In this study, a workflow is presented that delivers a representative average semi-axis length of ellipsoidal pores in carbonate rocks based on the pore aspect ratio received from velocity interpretation and the pore-surface-to-pore-volume ratio Spor as input parameters combined with theoretical calculations for ellipsoidal inclusions. A novel method to calculate Spor from NMR data based on the ratio of capillary-bound to movable fluids and the thickness of the capillary-bound water film is used. To test the workflow, a comprehensive petrophysical database was compiled using micritic and oomoldic Lower Muschelkalk carbonates from Germany. The experimental data indicate that both mud-dominated and grain-dominated carbonates possess distinct ranges of petrophysical parameters. The agreement between the predicted and measured surface-to-volume ratio is satisfying for oomoldic and most micritic samples, while pyrite or significant sample heterogeneity may lead to deviations. Selected photo-micrographs and scanning electron microscope images support the validity of the estimated representative pore dimensions.

Calculation of Regge Trajectories of Strange Resonances and Identification of the $K_0^*(800)$ as a Non-ordinary Meson

We review how the Regge trajectory of an elastic resonance can be obtained just from its pole position and coupling, using a dispersive formalism. This allows us to deal correctly with the finite widths of resonances in Regge trajectories. In this way, we can calculate the Regge trajectories for the K* (892), K_1(1400) and K_(0)^(*)(1430), obtaining ordinary linear Regge trajectories, expected for qq resonances. In contrast, for the K_(0)^(*)(800) meson, the resulting Regge trajectory is non-linear and with much smaller slope, strongly supporting its non-ordinary nature.

Acoustic scattering of a complex target with partially solid-filling immersed in water: numerical simulation and experiment

Resonance peaks of spectral function transformed from echoes are the most important characteristics for distinguishing the different targets. So in frequency domain, response function is usually calculated with small interval in a wider frequency band to satisfy the demand of fast and high precision prediction in practical engineering. According to axis-symmetric model, we use 2 dimensional finite element method to solve the acoustic scattering problem efficiently, even when the scattering target has a large size and complex structure. This article focuses on the explanation of scattering characteristics of a special target, namely, a partially solid-filling cylinder with hemispherical cap and thin-shell. Supposing that the receiver and transmitter are in monostatic arrangement, we calculate scattering strength in far field in a frequency range of 50 Hz-10 kHz, and give pseudo-color image represented by frequency-angle to describe influences of shell, filling and the orientation of the incident wave on scattering properties. According to the numerical results, the following conclusions are given: when the transmitter is facing the hemispherical cap (the cap has a vacuum inside, and the incident angle θ is equal to 0°), the main contribution of scattered wave comes from the shell of target. When θ = 180°, the internal filling inhibits the elastic resonance of the shell, and plays an important role in the total scattering field. Because the acoustic impedance of the shell is much larger than that of the water, elastic resonance of the shell is more difficult to excite than that of the solid filling. While the material property of the solid filling is not significantly different from that of the water, so the elastic resonance of the filling fluctuates relatively fast, and the scattering function vibrates approximately with equal amplitude in a wider frequency band. When θ= 90°, the sound wave is perpendicular to the axis of the cylinder, the shell and the filling work together on scattered waves. Once the incident angle deviates from 90° and the sound wave obliquely illuminates target with respective to the axis of the cylinder, the echo of the filling material plays a predominant role in the total scattering field. The frequency-angle spectrum of the solid filling model presents the “bowl” type resonance curve. In order to validate which physical and geometrical structure must be considered in solution of scattered far field, the acoustic scattering experiments are performed in tank with a target suspending in water, which is in monostatic arrangement and satisfies the free field condition. Frequency of incident wave is in a frequency range of 10-40 kHz. For obtaining pseudo-color image of distance-angle, echoes are received and measured when the target is rotated from 0°-360°. The scattered waves are divided into mirror reflection and various components of elastic wave, and the mechanisms of these echoes are explained based on circumferential wave around the surface. Whispering gallery waves are also considered and clearly seen in the experiment. Due to the coupling interaction between the filling and elastic shell, the resonance curve of frequency-angle spectrum splays “bowl” curve outward the sides of normally direction. Experimental and numerical results are in good agreement, which is indicated by comparing the resonance peaks characteristic in spectral domain. The results of this article will be helpful in studying underwater target with more complicated structure.

Excited-to-excited-state scattering using weak measurements

Weak measurements are a subset of measurement processes in quantum mechanics wherein the system, which is being measured, interacts very weakly with the measuring apparatus. Measurement values of observables undergoing a weak interaction and their amplification are concepts that have sharpened our understanding of interaction processes in quantum mechanics. Recent experiments show that naturally occurring processes such as resonance fluorescence from excited states of an atom can exhibit weak value amplification effect. In this paper we theoretically analyze the process of elastic resonance fluorescence from a $\mathsf{V}$-type three-level atomic system, using the well-known Weiskopff-Wigner (WW) theory of spontaneous emission. Within this theory we show that a weak interaction regime can be identified and for suitable choices of initial and final excited states the mean scattering time between these states show an amplification effect during interaction with the vacuum bath modes of the electromagnetic field. We thus show that a system-bath interaction can show weak value amplification. Using our theory we reproduce the published experimental results carried out in such a system. More importantly, our theory can calculate scattering time scales in elastic resonance scattering between multiple excited states of a single atom or between common excited state configurations of interacting multiatom systems.

A microwave detection way by electromagnetic and elastic resonance: Breaking the bottleneck of spatial resolution in microwave imaging

The spatial resolution of microwave imaging depends on the geometrical size of the detector. The existing techniques mainly focus on optimizing the antenna design to achieve high detection sensitivity. However, since the optimal antenna size is closely related to the wavelength to be measured, and the miniaturization of the geometrical size is challenging, this limits the spatial resolution of microwave imaging. In this letter, a microwave detection technique based on the electromagnetic-elastic resonance effect is proposed. The piezoelectric materials can produce mechanical responses under microwave excitation, and the amplitude of the microwave can be detected by measuring these responses. In contrast to conventional microwave detection method, the proposed method has distinct advantages in terms of high sensitivity and wide spectral response. Most importantly, it overcomes the limitation of detector size, thus, significantly improving the detection resolution. Therefore, the proposed method has potential for microwave imaging in biomedical applications.

Energy-loss of He ions in carbon allotropes studied by elastic resonance in backscattering spectra

Backscattering spectra for 4He ions incident on carbon allotropes have been measured in the energy range from 4.30 to 4.95MeV in steps of 50–100keV at scattering angles of 106° and 170°. We used three carbon allotropes: graphite, diamond and amorphous carbon. For all these allotropes, we can observe the sharp (4He, 12C) elastic nuclear resonance at the He ion energy of 4.265MeV in the backscattering spectra. By varying the incident He energy, we have systematically analyzed the profiles of the resonance peaks to study the energy-loss processes: stopping cross-sections and energy-loss straggling around the interesting region of the stopping maximum at about 500keV. We focus on the resonance profiles and investigate an allotropic effect concerning the energy-loss. Furthermore, an energy bunching effect on the straggling is presented and the mechanism is discussed.

Hydrogen interstitial in H-ion implanted ZnO bulk single crystals: Evaluation by elastic recoil detection analysis and electron paramagnetic resonance

The origins of low resistivity in H ion-implanted ZnO bulk single crystals are evaluated by elastic recoil detection analysis (ERDA), electron paramagnetic resonance (EPR), and Van der Pauw methods. The H-ion implantation (peak concentration: 5.0×1015cm−2) into ZnO is performed using a 500keV implanter. The maximum of the concentration of the implanted H estimated by a TRIM simulation is at 3600nm in depth. The resistivity decreases from ∼103Ωcm for un implanted ZnO to 6.5Ωcm for as-implanted, 2.3×10−1Ωcm for 200°C annealed, and 3.2×10−1Ωcm for 400°C annealed samples. The ERDA measurements can evaluate the concentration of hydrogens which move to the vicinity of the surface (surface to 300nm or 100nm) because of the diffusion by the annealing at 200°C and 400°C. The hydrogen concentration near the surface estimated using the 2.0MeV helium beam is ∼3.8×1013cm−2 for annealed samples. From EPR measurements, the oxygen vacancy of +charge state (Vo+) is observed in as-implanted samples. The Vo+ related signal (g=1.96) observed under no illumination disappears after successive illumination with a red LED and appears again with a blue light illumination. The activation energy of as-implanted, 200°C annealed, and 400°C annealed samples estimated from the temperature dependence of carrier concentration lies between 29meV and 23meV, suggesting the existence of H interstitial as a shallow donor level.

New measurement of the excited states inB11via elastic resonance scattering ofBe10+p

The elastic resonance scattering protons decayed from $^{11}\mathrm{B}$ to the ground state of $^{10}\mathrm{Be}$ were measured by using the thick-target technique in inverse kinematics at the Heavy Ion Research Facility in Lanzhou (HIRFL). The obtained excitation functions were well described by a multichannel $R$-matrix procedure under the kinematics process assumption of resonant elastic scattering. The excitation energy of the resonant states ranges from 13.0 to 17.0 MeV, and their resonant parameters such as the resonant energy ${E}_{x}$, the spin-parity ${J}^{\ensuremath{\pi}}$, and the proton-decay partial width ${\ensuremath{\Gamma}}_{p}$ were determined from $R$-matrix fits to the data. Two of these states around ${E}_{x}=14.55$ MeV [${J}^{\ensuremath{\pi}}=(3/{2}^{+},5/{2}^{+}),\phantom{\rule{4pt}{0ex}}{\ensuremath{\Gamma}}_{p}=475\ifmmode\pm\else\textpm\fi{}80$ keV] and ${E}_{x}=14.74$ MeV [${J}^{\ensuremath{\pi}}=3/{2}^{\ensuremath{-}},{\ensuremath{\Gamma}}_{p}=830\ifmmode\pm\else\textpm\fi{}145$ keV], and a probably populated state at ${E}_{x}=16.18$ MeV [${J}^{\ensuremath{\pi}}=(1/{2}^{\ensuremath{-}},3/{2}^{\ensuremath{-}}),\phantom{\rule{4pt}{0ex}}{\ensuremath{\Gamma}}_{p}\phantom{\rule{4pt}{0ex}}<60$ keV], are respectively assigned to the well-known states in $^{11}\mathrm{B}$ at 14.34, 15.29, and 16.43 MeV. The isospin of these three states were previously determined to be $T=3/2$, but discrepancies exist in widths and energies due to the current counting statistics and energy resolution. We have compared these states with previous measurements, and the observation of the possibly populated resonance is discussed.

On the traceably accurate voltage calibration of electrostatic accelerators

We describe in detail a calibration method for the terminal voltage of small accelerators used for ion beam analysis, with the elastic resonance of 16O(α,α)16O at 3038keV as the intrinsic measurement standard. The beam energy relative to this resonance is determined with a precision around 300eV and an evaluated reproducibility of 1.0keV. We show that this method is both robust and convenient, and demonstrate consistency with calibration relative to three other independent methods: using radioactive sources and using the resonant 27Al(p,γ)28Si and non-resonant 16O(p,γ)17F direct capture reactions. We re-evaluate the literature and show that the peak in the cross-section function is at 3038.1±2.3keV. By comparing the results obtained with 16O(α,α)16O to the other calibration methods we show that this uncertainty can be reduced to 1.3keV.

Phonon-assisted Andreev reflection in a hybrid junction based on a quantum dot

Spin-dependent tunneling through a quantum dot coupled to one ferromagnetic and one superconducting electrodes is investigated in the Andreev reflection (AR) regime occurring in the presence of the on-dot electron-phonon interactions. Current-voltage characteristics of the system are evaluated within the nonequilibrium Green function technique. Features of the AR current due to interplay between the electron-phonon interactions, intradot Coulomb correlations and the polarization of the ferromagnetic electrode are analyzed in both linear and nonlinear transport regimes. It is shown that for the case of electron-hole symmetry, the phonon resonances may appear on both sides of the main elastic resonances in spectral function. A phonon-induced renormalization of the Andreev transmission levels is found and splitting of the phonon side bands for nonvanishing intradot Coulomb repulsion is observed. It is shown that linear conductance exhibits the polaron shift and suppression in the presence of the polaron transmission. In nonequilibrium situation the mechanism of the negative differential conductance (NDC) in the presence of competing magnetic electrode polarisation and the Coulomb correlations on the dot is analyzed. An influence of the polaron transmission through the Andreev intradot states on the NDC oscillations is also discussed.

In-plane time-harmonic elastic wave motion and resonance phenomena in a layered phononic crystal with periodic cracks.

This paper presents an elastodynamic analysis of two-dimensional time-harmonic elastic wave propagation in periodically multilayered elastic composites, which are also frequently referred to as one-dimensional phononic crystals, with a periodic array of strip-like interior or interface cracks. The transfer matrix method and the boundary integral equation method in conjunction with the Bloch-Floquet theorem are applied to compute the elastic wave fields in the layered periodic composites. The effects of the crack size, spacing, and location, as well as the incidence angle and the type of incident elastic waves on the wave propagation characteristics in the composite structure are investigated in details. In particular, the band-gaps, the localization and the resonances of elastic waves are revealed by numerical examples. In order to understand better the wave propagation phenomena in layered phononic crystals with distributed cracks, the energy flow vector of Umov and the corresponding energy streamlines are visualized and analyzed. The numerical results demonstrate that large energy vortices obstruct elastic wave propagation in layered phononic crystals at resonance frequencies. They occur before the cracks reflecting most of the energy transmitted by the incoming wave and disappear when the problem parameters are shifted from the resonant ones.

Anisotropic Elastic Resonance Scattering Model for the Neutron Transport Equation

The resonance scattering transfer cross section has been reformulated to account for anisotropic scattering in the center of mass of the neutron-nucleus system. The main innovation over previous implementations is the relaxation of the ubiquitous assumption of isotropic scattering in the center of mass and the actual effective use of scattering angle distributions from evaluated nuclear data files in the computation of the angular moments of the resonant scattering kernels. The formulas for the high-order anisotropic moments in the laboratory system are also derived. A multigroup numerical formulation is derived and implemented into a module incorporated within the NJOY nuclear data processing code. An ultrafine-energy-mesh cross-section library was generated using these new theoretical models and then was used for fuel assembly calculations with the PARAGON lattice physics code. The results obtained indicate that this new model makes a significant difference to predictions of reactivity, multigroup fluxes, and isotopic inventory during depletion.

Establishing Empirical Period Formula for RC Buildings in Lima, Peru: Evidence for the Impact of Both the 1974 Lima Earthquake and the Application of the Peruvian Seismic Code on High-Rise Buildings

Online Material: Table describing reinforced concrete buildings measured in Lima, Peru. The easiest building parameter to determine is the elastic fundamental resonance period, or its inverse, the fundamental frequency, preferentially used in seismological studies. This period/frequency is directly related to the building stiffness and can be linked to external inputs (acceleration, soil response, etc.), internal history (construction material and quality, structural design, seismic history, etc.), and more complicated factors such as soil–structure interaction. This frequency is generally obtained through building modeling for the most recent structures but is much more complicated or even impossible to determine for old buildings, the blueprints of which are generally not available. This crucial parameter can be directly assessed in situ using (1) dynamic methods, such as unbinding, harmonic excitation, or percussion (e.g., Trifunac, 1972; Boutin et al. , 2001; Crowley and Pinho, 2004) that are expensive, tedious to install, and generally disturbing, (2) traditional earthquake records (e.g., Dunand et al. , 2006; Todorovska, 2009), or (3) passive ambient vibration recordings (e.g., Carder, 1936; Trifunac, 1972; Trifunac et al. , 2001a,b; Farsi and Bard, 2004; Michel et al. , 2008; Farsi et al. , 2009; Michel, Gueguen, El Arem, et al. , 2010) or other passive method such as coherent Light Detection and Ranging measurement (Gueguen et al. , 2010). The most reliable building dynamic parameter estimates are obtained from earthquake records, but this type of data is quite difficult to obtain, very expensive because of the seismic network deployment and maintenance, and heavily dependent on earthquake occurrence, which may be quite a problem in low‐to‐moderate seismic regions. Ambient vibration recordings performed on building are recognized to provide larger fundamental frequency than those used for earthquake engineering purposes. In spite of this, ambient vibration studies allow to collect numerous data, allowing statistical processing, which …

Spectroscopy of equilibrium and nonequilibrium charge transfer in semiconductor quantum structures

We investigate equilibrium and non-equilibrium charge-transfer processes by performing high-resolution transport spectroscopy. Using electrostatically defined quantum dots for energy-selective emission and detection, we achieved unprecedented spectral resolution and a high degree of tunability of relevant experimental parameters. Most importantly, we observe that the spectral width of elastically transferred electrons can be substantially smaller than the linewidth of a thermally broadened Coulomb peak. This finding indicates that the charge-transfer process is fast compared to the electron--phonon interaction time. By drawing an analogy to double quantum dots, we argue that the spectral width of the elastic resonance is determined by the lifetime broadening $h\it{\Gamma}$ of the emitter and detector states. Good agreement with the model is found also in an experiment in which the charge transfer is in the regime $h\it{\Gamma}\gg k_{\rm{B}}T$. By performing spectroscopy below the Fermi energy, we furthermore observe elastic and inelastic transfer of holes.

The effect of elastic point contact and mechanical resonators

We present a novel analytical treatment of nearfield elasticity effects in mechanical resonator systems, which shows that local strain fields near a point contact can be accounted for by introducing a spring-like contact impedance at appropriate interfaces. We demonstrate via experiment that such effects can cause significant shifts in resonant frequency, and predict that the local displacements give rise to an additional dissipation mechanism which can be significant. The mathematical expressions we obtain are simple enough as to be easily included in traditional engineering models that are typically used to approximate the results one would obtain via true three-dimensional elasticity theory calculations. The effects we describe are scale invariant; we briefly discuss potentially relevant biological, nanomechanical, and large-scale systems.