Journal articles: 'Wave-packet analysis'

1

Ghaani Farashahi, Arash. "Multivariate Wave-Packet Transforms." Zeitschrift für Analysis und ihre Anwendungen 36, no. 4 (2017): 481–500. http://dx.doi.org/10.4171/zaa/1598.

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Xiao, Tian Gui, Yao Wu, and Rong Hua Jin. "Analysis on the Characteristics of Scale Wave Energy Dynamic System during Extended Period of the Massive Drought in Southwestern Region." Applied Mechanics and Materials 164 (April 2012): 460–66. http://dx.doi.org/10.4028/www.scientific.net/amm.164.460.

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Through the wave-packet propagation diagnosis (WPD), the essay discusses and analyzes the characteristics of wave packet distribution and dynamic system of wave energy propagation during the extended period of the massive drought in southwestern region in the country by using the reanalysis grid data of the daily NCEP/NCAR geopotential height field and 10×10 horizontal resolution from September 2009 to April 2010. The results show that: the characteristics of dynamic system of wave energy propagation at the middle and high height fields can better reflect the stage features of this drought during the period. The wave energy time-variation chart shows that the wave disturbance during the drought is weak and the wave packet value is small. However, the wave packet value during the drought still has some changes, reflecting the characteristics of the drought change in weakness. At the maintenance period of the wave packet value, the drought is often severe, and when the wave packet value changes greatly, the magnitude of the drought will change. Seen from the characteristics of longitudinal and altitudinal propagation of the wave energy, when the wav packet strength increases, the energy will accumulate and the drought tends to be weakened; on the contrary, when the wave packet strength decreases, energy will discharge and the drought will become more severe—particularly when the wave packet weakens quickly, the drought will become more drastic. This study provides a meaningful idea for discussing the forecast of the scale weather process during the extended period.

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Xie, Peng, and Yi Zhu. "Wave packet dynamics in slowly modulated photonic graphene." Journal of Differential Equations 267, no. 10 (November 2019): 5775–808. http://dx.doi.org/10.1016/j.jde.2019.06.006.

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Yatskikh, Aleksey, Yury Yermolaev, Alexander Kosinov, Nikolai Semionov, and Alexander Semenov. "Evolution of localized artificial disturbance in 2D and 3D supersonic boundary layers." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 234, no. 1 (July 12, 2018): 115–23. http://dx.doi.org/10.1177/0954410018787120.

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The evolution of a controlled broadband wave packet in flat-plate and swept-wing supersonic boundary layers was experimentally investigated at Mach number M = 2. The wave packet was introduced into the boundary layer by a localized pulse electrical discharge. The structure and evolution downstream of the wave packet were studied by hot-wire measurements. It was found that the wave packet has a symmetric shape in a flat-plate boundary layer, whereas there is asymmetry in case of a swept-wing one. The spectral analysis of the development of different modes of the wave packet was provided.

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Xu, Meiyu, Dayong Lu, and Qibin Fan. "Construction of -stage discrete periodic wave packet frames." Applicable Analysis 97, no. 11 (June 23, 2017): 1846–66. http://dx.doi.org/10.1080/00036811.2017.1343465.

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Liu, Xiaolong, Xinran Li, Ya Meng, Changqin Chen, and Yang Yang. "Optimized wavelet packet analysis for photovoltaic wave power suppression." International Journal of Low-Carbon Technologies 17 (November 27, 2021): 90–96. http://dx.doi.org/10.1093/ijlct/ctab089.

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Abstract The hybrid energy storage system (HESS) is composed of lithium-ion battery packs and supercapacitors (SCs), it can better stabilize the output of photovoltaic (PV) in the microgrid. The wavelet packet analysis method is used to decompose the output power of PV, and the power components of different frequency bands can be obtained. However, the traditional wavelet packet decomposition method has a fixed number of decomposition layers and cannot track changes in the output power of PV in real time. This paper proposes an improved wavelet packet decomposition method: considering the fluctuation of solar cell output power and the current working status of the HESS, the fuzzy control algorithm is used to adjust the number of wavelet packet layers in real-time to realize the adaptive process of power fluctuation in the stable process, and taking into account the state of charge of lithium-ion batteries and SCs, fuzzy control is used to allocate their secondary output power to improve the stability effect. Experiments show that compared with the traditional wavelet packet-based control method, the control method proposed in this paper improves the control effect by 4.5%.

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Ghaani Farashahi, Arash. "Square-integrability of metaplectic wave-packet representations onL2(R)." Journal of Mathematical Analysis and Applications 449, no. 1 (May 2017): 769–92. http://dx.doi.org/10.1016/j.jmaa.2016.12.033.

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Gorman, Arthur D., and Huijun Yang. "Caustic consideration of long planetary wave packet analysis in the continuously stratified ocean." International Journal of Mathematics and Mathematical Sciences 25, no. 1 (2001): 63–72. http://dx.doi.org/10.1155/s0161171201005002.

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The wave packet method, one form of the WKB technique, recently has been employed to investigate the evolution of long planetary wave packets in relation to the complex climate variability in the world oceans. However, such a method becomes invalid near the caustics. Here, the Lagrange manifold formalism is used to extend this analysis to include the caustic regions. We conclude that even though the wave packet method fails near the caustics, the equations derived from this method away from caustics are identical to ones from the Lagrange manifold formalism near caustics

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Ghosh, Suranjana, and J. Banerji. "A time–frequency analysis of wave packet fractional revivals." Journal of Physics B: Atomic, Molecular and Optical Physics 40, no. 17 (August 28, 2007): 3545–53. http://dx.doi.org/10.1088/0953-4075/40/17/021.

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Mies, F. H., and A. Giusti-Suzor. "Wave-packet analysis of laser-induced half-collision processes." Physical Review A 44, no. 11 (December 1, 1991): 7547–59. http://dx.doi.org/10.1103/physreva.44.7547.

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Xiao, Qi Jun, and Zhong Hui Luo. "Time-Frequency Characteristics of Vibration Signals Analysis for Large Instantaneous Impact Mill Rolling Based on Wavelet Packet." Advanced Materials Research 834-836 (October 2013): 1061–64. http://dx.doi.org/10.4028/www.scientific.net/amr.834-836.1061.

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The wavelet packet decomposition and reconstruction technique is applied to time-frequency analysis of bite steel impact vibration signal by big rolling machine, it is obtained the bite steel impact signal wave packet. According to the size of the wavelet packet energy, it is reconstructed the signal of No.1 and No.2 wavelet packet. According to reconstruction of the signal time domain waveform and FFT spectrum chart, some meaningful conclusions are obtained.

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Hasanov, Afig, Ruslan Hasanov, Asad Rustamov, Elgun Agayev, Vugar Eynullayev, Rovshan Ahmadov, and Masud Sadikhov. "Development of an axonometric model of photoelastic interaction in an acousto-optic delay line and its approbation." Technology audit and production reserves 5, no. 2(67) (November 25, 2022): 38–45. http://dx.doi.org/10.15587/2706-5448.2022.267782.

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The object of research is a mathematical model of the photoelastic interaction in an acousto-optic delay line (AODL). Two possible cases are discussed as applied to the ratio of the input pulse duration to the time of crossing the optical beam by an elastic wave packet. It is shown that in both cases the voltage at the output of the device is found as the sum of three components, which are formed by different mechanisms. If the duration of the input pulse is longer than the time of crossing the optical beam by an elastic wave packet, then the first component is determined by the process of entry of the leading edge of the elastic wave packet into the optical beam, the second – by the process of complete interaction of the optical beam with the elastic wave packet, and the third – by the process of exit of the trailing edge of the elastic wave packet from the optical beam. In the second case, i. e. when the duration of the input pulse is less than the time of crossing the optical beam by an elastic wave packet, the first term is determined by the process of entry of the elastic wave packet into the optical beam, the second – by the process of advancing the elastic wave packet in the aperture of the optical beam, and the third – by the process of exit of the elastic wave packet from the aperture of the optical beam. The corresponding equations for calculating the parameters of the output pulse were obtained by applying a rectangular pulse to the AODL input. It is proved that if the pulse duration at the AODL input is longer than the time of intersection of the optical beam by an elastic wave packet, then the pulse duration at its output will be equal to the duration of the input pulse. In the case when the duration of the input pulse is less than the time of crossing the optical beam by an elastic wave packet, the duration of the output pulse will be determined by the time of propagation of the elastic wave packet in the aperture of the optical beam. The obtained equations are confirmed by numerical calculations. The results of the numerical analysis were tested experimentally, which confirms the unequivocal adequacy of the proposed model of photoelastic interaction in an AODL.

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Kaczor, Urszula, Bogusław Klimas, Dominik Szydłowski, Maciej Wołoszyn, and Bartłomiej J. Spisak. "Phase-space description of the coherent state dynamics in a small one-dimensional system." Open Physics 14, no. 1 (October 1, 2016): 354–59. http://dx.doi.org/10.1515/phys-2016-0036.

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AbstractThe Wigner-Moyal approach is applied to investigate the dynamics of the Gaussian wave packet moving in a double-well potential in the ‘Mexican hat’ form. Quantum trajectories in the phase space are computed for different kinetic energies of the initial wave packet in the Wigner form. The results are compared with the classical trajectories. Some additional information on the dynamics of the wave packet in the phase space is extracted from the analysis of the cross-correlation of the Wigner distribution function with itself at different points in time.

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Ghaani Farashahi, Arash. "Wave packet transforms over finite cyclic groups." Linear Algebra and its Applications 489 (January 2016): 75–92. http://dx.doi.org/10.1016/j.laa.2015.10.001.

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FINSTER, FELIX, and JOEL SMOLLER. "A TIME-INDEPENDENT ENERGY ESTIMATE FOR OUTGOING SCALAR WAVES IN THE KERR GEOMETRY." Journal of Hyperbolic Differential Equations 05, no. 01 (March 2008): 221–55. http://dx.doi.org/10.1142/s0219891608001453.

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The Cauchy problem for the scalar wave equation in the Kerr geometry is considered, with initial data which is smooth and compactly supported outside the event horizon. A time-independent energy estimate for the outgoing wave is obtained. As an application, the outgoing energy for wave-packet initial data is estimated, uniformly as the support of the initial data is shifted to infinity. The main mathematical tool is the previously derived integral representation of the wave propagator.

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DE LEO, STEFANO, CELSO C. NISHI, and PIETRO P. ROTELLI. "WAVE PACKETS AND QUANTUM OSCILLATIONS." International Journal of Modern Physics A 19, no. 05 (February 20, 2004): 677–94. http://dx.doi.org/10.1142/s0217751x04017689.

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We give a detailed analysis of the oscillation formula within the context of the wave packet formalism. Particular attention is made to insure flavor eigenstate creation in the physical cases (Δp≠0). This requirement imposes noninstantaneous particle creation in all frames. It is shown that the standard formula is not only exact when the mass wave packets have the same velocity, but it is a good approximation when minimal slippage occurs. For more general situations the oscillation formula contains additional arbitrary parameters, which allows for the unknown form of the wave packet envelope.

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Matijošius, A., R. Piskarskas, E. Gaižauskas, A. Dubietis, and P. Di Trapani. "Space-Time Recovery of Arbitrarily Shaped Wave-Packets by Means of Three Dimensional Imaging Technique." Nonlinear Analysis: Modelling and Control 9, no. 3 (July 25, 2004): 259–70. http://dx.doi.org/10.15388/na.2004.9.3.15157.

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We study numerically and experimentally self-focusing dynamics of femtosecond light pulses. By demonstrating the potential of three dimensional imaging technique for quantitative recovery of complex (arbitrarily shaped) wave packets, we monitor space-time transformation dynamics of 150-fs light pulse, which undergoes self-focusing and filamentation in water. Peculiar spatiotemporal and spectral features reveal conical nature of resulting wave-packet.

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Cordero, Elena, Fabio Nicola, and Luigi Rodino. "Wave packet analysis of Schrödinger equations in analytic function spaces." Advances in Mathematics 278 (June 2015): 182–209. http://dx.doi.org/10.1016/j.aim.2015.03.014.

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19

Cao, Jianshu, and Kent R. Wilson. "Detecting wave packet motion in pump–probe experiments: Theoretical analysis." Journal of Chemical Physics 106, no. 12 (March 22, 1997): 5062–72. http://dx.doi.org/10.1063/1.473552.

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20

Kang, Byung Ho, and Kyu Han Kim. "Wave Data Analysis for Wave Energy Power in Namae Coast." Applied Mechanics and Materials 672-674 (October 2014): 446–52. http://dx.doi.org/10.4028/www.scientific.net/amm.672-674.446.

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In order to install the wave power facilities in ocean and coastal area, it is very important to determine the properties of wave data. Discrete wavelet packet transform was applied in this study and was used as a tool to find out the basic properties of waves around Namae coast. Important features of hydrodynamic pressure such as frequency and magnitude were investigated in different observation time. Also the idea of measuring the noise rate was introduced and applied to both stationary and non-stationary time spans for the comparison. These methods would be useful to check the feasibility of wave energy extraction in various types of coasts.

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Putra, Fima Ardianto. "De Broglie Wave Analysis of the Heisenberg Uncertainty Minimum Limit under the Lorentz Transformation." Jurnal Teras Fisika 1, no. 2 (September 20, 2018): 1. http://dx.doi.org/10.20884/1.jtf.2018.1.2.1008.

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A simple analysis using differential calculus has been done to consider the minimum limit of the Heisenberg uncertainty principle in the relativistic domain. An analysis is made by expressing the form of and based on the Lorentz transformation, and their corresponding relation according to the de Broglie wave packet modification. The result shows that in the relativistic domain, the minimum limit of the Heisenberg uncertainty is p x ?/2 and/or E t ?/2, with is the Lorentz factor which depend on the average/group velocity of relativistic de Broglie wave packet. While, the minimum limit according to p x ?/2 or E t ?/2, is the special case, which is consistent with Galilean transformation. The existence of the correction factor signifies the difference in the minimum limit of the Heisenberg uncertainty between relativistic and non-relativistic quantum. It is also shown in this work that the Heisenberg uncertainty principle is not invariant under the Lorentz transformation. The form p x ?/2 and/or E t ?/2 are properly obeyed by the Klein-Gordon and the Dirac solution. Key words: De Broglie wave packet, Heisenberg uncertainty, Lorentz transformation, and minimum limit.

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Decker, Steven G., and Jonathan E. Martin. "A Local Energetics Analysis of the Life Cycle Differences between Consecutive, Explosively Deepening, Continental Cyclones." Monthly Weather Review 133, no. 1 (January 1, 2005): 295–316. http://dx.doi.org/10.1175/mwr-2860.1.

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Abstract Local energetics diagnostics of the life cycles of consecutive, explosively deepening, extratropical cyclones that migrated across central North America in April 2001 are presented. Both storms developed rapidly and followed nearly identical tracks through the region. Despite similar mature-stage intensities, the two storms underwent vastly different evolutions during cyclolysis; the first decayed as rapidly as it had developed, and the second decayed very slowly. Examination of the volume-integrated eddy kinetic energy (EKE) budget for each storm reveals that the sea level pressure minimum associated with the first cyclone developed well after its associated EKE center had reached its maximum intensity. In contrast, the second cyclone’s sea level pressure minimum developed much more in concert with the development of its associated EKE center. As a consequence, the first cyclone began losing EKE through downstream energy fluxes even as it was developing at the surface, whereas the second cyclone did not disperse EKE downstream until later in its life cycle. Consideration of the EKE budget results in terms of baroclinic wave packets demonstrates that the first cyclone developed and decayed on the upstream edge of a wave packet, whereas the second cyclone developed in the midst of a wave packet, only decaying once it had reached the upstream edge. Thus, it is suggested that postmature phase decay is dynamically linked to a cyclone’s position in a given wave packet.

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Velichko, S., A. Matveev, D. Bychkov, V. Ivanov, V. Tsymbal, and O. Gavrilenko. "Radar monitoring of long surface waves in the pacific ocean." RADIOFIZIKA I ELEKTRONIKA 26, no. 1 (2021): 3–11. http://dx.doi.org/10.15407/rej2021.01.003.

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Subject and Purpose. The paper addresses interaction processes going in the ocean–atmosphere system and is concerned with their research by the method of radar remote sensing. Specifically, the matter of concern is the detection and parameter estimation of long waves, including nonlinear ones, on the ocean surface. Methods and Methodology. In August 1988, a series of successive radar surveys of long surface wave manifestations on the Pacific Ocean surface was carried out in the 3 cm wave range by means of an airborne X-band radar system “Analog”. The analysis of the results includes estimation of both spatial and frequency features of the detected long-wave packets and, also, a comparison of the measurement results with model calculations performed in the framework of theory of radio wave scattering by the sea surface in the presence of seismic wave effects. Results. Radar images of wave packets of long surface waves in the open ocean have been obtained. From the imaging data, the spatial scale (5…10 km) of these waves, the lengths (1…5 km) of wave packet components and the wave packet velocity (6.1 m/s) have been derived. Analysis has been given to the nonlinear form of wave packet components, and their amplitudes have been estimated by comparing the experimental and theoretically obtained radio contrasts. The bathymetry of the surface-wave track has been performed to suggest that the observed wave packet represents a set of solitons generated by a seismic impact with the further underwater collapse. Conclusions. A possibility has been demonstrated for monitoring wave packets of long surface waves in their propagation dynamics. The experiments of the sort for gaining a deeper insight into the ocean–atmosphere interaction physics can be conducted by means of not only airborne but also spaceborne radar systems with allowance made for the rate of surveys in both time and space.

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Rieper, Felix, U. Achatz, and R. Klein. "Range of validity of an extended WKB theory for atmospheric gravity waves: one-dimensional and two-dimensional case." Journal of Fluid Mechanics 729 (July 19, 2013): 330–63. http://dx.doi.org/10.1017/jfm.2013.307.

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AbstractA computational model of the pseudo-incompressible equations is used to probe the range of validity of an extended Wentzel–Kramers–Brillouin theory (XWKB), previously derived through a distinguished limit of a multiple-scale asymptotic analysis of the Euler or pseudo-incompressible equations of motion, for gravity-wave packets at large amplitudes. The governing parameter of this analysis had been the scale-separation ratio $\varepsilon $ between the gravity wave and both the large-scale potential-temperature stratification and the large-scale wave-induced mean flow. A novel feature of the theory had been the non-resonant forcing of higher harmonics of an initial wave packet, predominantly by the large-scale gradients in the gravity-wave fluxes. In the test cases considered a gravity-wave packet is propagating upwards in a uniformly stratified atmosphere. Large-scale winds are induced by the wave packet, and possibly exert a feedback on the latter. In the limit $\varepsilon \ll 1$ all predictions of the theory can be validated. The larger $\varepsilon $ is the more the transfer of wave energy to the mean flow is underestimated by the theory. The numerical results quantify this behaviour but also show that, qualitatively, XWKB remains valid even when the gravity-wave wavelength approaches the spatial scale of the wave-packet amplitude. This includes the prevalence of first and second harmonics and the smallness of harmonics with wave number higher than two. Furthermore, XWKB predicts for the vertical momentum balance an additional leading-order buoyancy term in Euler and pseudo-incompressible theory, compared with the anelastic theory. Numerical tests show that this term is relatively large with up to $30\hspace{0.167em} \% $ of the total balance. The practical relevance of this deviation remains to be assessed in future work.

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Ghinassi, Paolo, Marlene Baumgart, Franziska Teubler, Michael Riemer, and Volkmar Wirth. "A Budget Equation for the Amplitude of Rossby Wave Packets Based on Finite-Amplitude Local Wave Activity." Journal of the Atmospheric Sciences 77, no. 1 (December 18, 2019): 277–96. http://dx.doi.org/10.1175/jas-d-19-0149.1.

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Abstract Recently, the authors proposed a novel diagnostic to quantify the amplitude of Rossby wave packets. This diagnostic extends the local finite-amplitude wave activity (LWA) of N. Nakamura and collaborators to the primitive-equations framework and combines it with a zonal filter to remove the phase dependence. In the present work, this diagnostic is used to investigate the dynamics of upper-tropospheric Rossby wave packets, with a particular focus on distinguishing between conservative dynamics and nonconservative processes. For this purpose, a budget equation for filtered LWA is derived and its utility is tested in a hierarchy of models. Idealized simulations with a barotropic and a dry primitive-equation model confirm the ability of the LWA diagnostic to identify nonconservative local sources or sinks of wave activity. In addition, the LWA budget is applied to forecast data for an episode in which the amplitude of an upper-tropospheric Rossby wave packet was poorly represented. The analysis attributes deficiencies in the Rossby wave packet amplitude to the misrepresentation of diabatic processes and illuminates the importance of the upper-level divergent outflow as a source for the error in the wave packet amplitude.

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GHOSH, SURANJANA. "COHERENT CONTROL OF MESOSCOPIC SUPERPOSITIONS IN A DIATOMIC MOLECULE." International Journal of Quantum Information 10, no. 02 (March 2012): 1250014. http://dx.doi.org/10.1142/s0219749912500141.

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A phase controlled wave packet, recently used in experiment of wave packet interferometry of a diatomic molecule, is investigated to obtain mesoscopic superposition structures, useful in quantum metrology. This analysis provides a new way of obtaining sub-Planck scale structures at smaller time scale of revival dynamics. We study a number of situations for delineating the smallest interference structures and their control by tailoring the relative phase between two subsidiary wave packets. We also find the most appropriate state, so far, for high precision parameter estimation in a system of diatomic molecule.

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Yoneyama, Taisuke, and Keiichi Kato. "Characterization of the Ranges of Wave Operators for Schrödinger Equations via Wave Packet Transform." Funkcialaj Ekvacioj 63, no. 1 (2020): 19–37. http://dx.doi.org/10.1619/fesi.63.19.

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Srivastava, Hari M., Firdous A. Shah, and Waseem Z. Lone. "Quadratic-Phase Wave-Packet Transform in L2(ℝ)." Symmetry 14, no. 10 (September 26, 2022): 2018. http://dx.doi.org/10.3390/sym14102018.

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Wavelet transform is a powerful tool for analysing the problems arising in harmonic analysis, signal and image processing, sampling, filtering, and so on. However, they seem to be inadequate for representing those signals whose energy is not well concentrated in the frequency domain. In pursuit of representations of such signals, we propose a novel time-frequency transform coined as quadratic-phase wave packet transform in L2(R). The proposed transform is aimed at rectifying the conventional wavelet transform by employing a quadratic-phase Fourier transform with extra degrees of freedom. Besides the formulation of all the fundamental results, including the orthogonality relation, reconstruction formula and the characterization of range, we also derive a direct relationship between the well-known Wigner-Ville distribution and the proposed transform. In addition, we study the quadratic-phase wave-packet transform in the framework of almost periodic functions. Finally, we extend the scope of the present work by investigating the composition of quadratic-phase wave packet transforms.

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Brunetti, R., and C. Jacoboni. "Wave-packet analysis of electron-phonon interaction in the Wigner formalism." Physical Review B 57, no. 3 (January 15, 1998): 1723–30. http://dx.doi.org/10.1103/physrevb.57.1723.

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Zhou, W. J., X. P. Li, Y. S. Wang, W. Q. Chen, and G. L. Huang. "Spectro-spatial analysis of wave packet propagation in nonlinear acoustic metamaterials." Journal of Sound and Vibration 413 (January 2018): 250–69. http://dx.doi.org/10.1016/j.jsv.2017.10.023.

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Chou, Chia-Chun. "Hydrodynamic analysis of the Schrödinger–Langevin equation for wave packet dynamics." Physics Letters A 381, no. 39 (October 2017): 3384–90. http://dx.doi.org/10.1016/j.physleta.2017.08.037.

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Tóth, A., S. Borbély, G. J. Halász, and Á. Vibók. "Strong field dissociative ionization of the D2+: Nuclear wave packet analysis." Chemical Physics Letters 683 (September 2017): 567–72. http://dx.doi.org/10.1016/j.cplett.2017.01.067.

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Pernot, P., and W. A. Lester. "Multidimensional wave-packet analysis: Splitting method for time-resolved property determination." International Journal of Quantum Chemistry 40, no. 5 (November 1991): 577–88. http://dx.doi.org/10.1002/qua.560400502.

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MEHDIPOUR, S. HAMID, KOUROSH NOZARI, and S. DAVOOD SADATIAN. "FRACTIONAL ANALYSIS OF WAVE PACKET PROPAGATION AND SOME ASPECTS OF VSL WITH GUP." Fractals 16, no. 01 (March 2008): 33–42. http://dx.doi.org/10.1142/s0218348x0800379x.

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In this paper, we consider the problem of wave packet broadening in the framework of the Generalized Uncertainty Principle (GUP) of quantum gravity. Then we find a fractal Klein-Gordon equation to further analyze the wave packet broadening in a foamy spacetime. We derive a Modified Dispersion Relation (MDR) in the context of GUP which shows an extra broadening due to gravitational induced uncertainty. As a result of these dispersion relations, a generalized Klein-Gordon equation can be obtained. We solve this generalized equation under certain conditions to find both analytical and numerical results. We show that GUP can lead to a variation of the fundamental constants such as speed of light. With this novel properties, we find a time-dependent equation of state for perfect fluid in de Sitter universe and we interpret its physical implications.

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Li, Lin, Wen Jun Hu, and Jun Lin Tao. "Attenuation Characteristics of Stress Wave Propagation in a Polycarbonate Rod Using Wavelet Packet Analysis." Applied Mechanics and Materials 723 (January 2015): 732–36. http://dx.doi.org/10.4028/www.scientific.net/amm.723.732.

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In this paper, a method of wavelet packet decomposition and multi-frequency band analysis is considered to study the amplitude attenuation characteristics of stress wave propagation in a viscoelastic polycarbonate (PC) rod. The reconstruction coefficients of different frequency bands could be acquired through wavelet packet decomposition and reconstruction. Associate conjugate gradient method with modified Sadaovsk formula to fit the curve of peak amplitude for each frequency band, from which the amplitude attenuation characteristics and attenuation rates of each frequency band with the increasing of the propagation distance were obtained. Predicted the waveform in the light of viscoelastic attenuation behavior of different frequency bands, it gives better mean square error (MSE) compared with the actual waveform. This result indicated that this method can effectively predict the propagation disciplinarian of the viscoelastic stress wave.

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Ghaani Farashahi, Arash. "Abstract harmonic analysis of wave-packet transforms over locally compact abelian groups." Banach Journal of Mathematical Analysis 11, no. 1 (January 2017): 50–71. http://dx.doi.org/10.1215/17358787-3721281.

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Moskalets, Michael. "Auto- versus Cross-Correlation Noise in Periodically Driven Quantum Coherent Conductors." Entropy 23, no. 4 (March 25, 2021): 393. http://dx.doi.org/10.3390/e23040393.

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Expressing currents and their fluctuations at the terminals of a multi-probe conductor in terms of the wave functions of carriers injected into the Fermi sea provides new insight into the physics of electric currents. This approach helps us to identify two physically different contributions to shot noise. In the quantum coherent regime, when current is carried by non-overlapping wave packets, the product of current fluctuations in different leads, the cross-correlation noise, is determined solely by the duration of the wave packet. In contrast, the square of the current fluctuations in one lead, the autocorrelation noise, is additionally determined by the coherence of the wave packet, which is associated with the spread of the wave packet in energy. The two contributions can be addressed separately in the weak back-scattering regime, when the autocorrelation noise depends only on the coherence. Analysis of shot noise in terms of these contributions allows us, in particular, to predict that no individual traveling particles with a real wave function, such as Majorana fermions, can be created in the Fermi sea in a clean manner, that is, without accompanying electron–hole pairs.

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Halfiani, Vera, Dwi Fadhiliani, Harish Abdillah Mardi, and Marwan Ramli. "Nonlinear Evolution of Benjamin-Bona-Mahony Wave Packet due to an Instability of a Pair of Modulations." International Journal of Differential Equations 2018 (June 3, 2018): 1–10. http://dx.doi.org/10.1155/2018/1716571.

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This article discusses the evolution of Benjamin-Bona-Mahony (BBM) wave packet’s envelope. The envelope equation is derived by applying the asymptotic series up to the third order and choosing appropriate fast-to-slow variable transformations which eliminate the resonance terms that occurred. It is obtained that the envelope evolves satisfying the Nonlinear Schrodinger (NLS) equation. The evolution of NLS envelope is investigated through its exact solution, Soliton on Finite Background, which undergoes modulational instability during its propagation. The resulting wave may experience phase singularity indicated by wave splitting and merging and causing amplification on its amplitude. Some parameter values take part in triggering this phenomenon. The amplitude amplification can be analyzed by employing Maximal Temporal Amplitude (MTA) which is a quantity measuring the maximum wave elevation at each spatial position during the observation time. Wavenumber value affects the extreme position of the wave but not the amplitude amplification. Meanwhile, modulational frequency value affects both terms. Comparison of the evolution of the BBM wave packet to the previous results obtained from KdV equation gives interesting outputs regarding the extreme position and the maximum wave peaking.

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Zhu, Dong Bi, and Dan Dan Zhu. "Performance Analysis of a Multi-Channel MAC with Dynamic CCH Interval in WAVE System." Advanced Materials Research 765-767 (September 2013): 2621–24. http://dx.doi.org/10.4028/www.scientific.net/amr.765-767.2621.

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To improve the throughput performance of the Wireless Access in Vehicular Environment (WAVE) system, we propose a multi-channel MAC protocol that is able to adaptively adjust the intervals of Control Channel (CCH) and Service Channel (SCH) according to the probability distribution of the reservation time for service packet in CCH Interval. Numerical results show that our protocol can significantly improve the performance of WAVE system.

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ZHANG, ZHIBO, ENYUAN WANG, YINGHUA ZHANG, SHUAI YANG, XIANAN LIU, MUHAMMAD ALI, and GUANSHENG QI. "ANALYSIS ON THE TIME-FREQUENCY CHARACTERISTICS OF ULTRASONIC WAVEFORM OF COAL UNDER UNIAXIAL LOADING." Fractals 27, no. 06 (September 2019): 1950100. http://dx.doi.org/10.1142/s0218348x19501007.

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Ultrasonic receiving wave can reflect physical properties and damage degree of coal samples. Therefore, it is of great significance to deeply study the parameters of ultrasonic. In this paper, time-domain characteristics of receiving wave are analyzed systematically, which present good correlation with stress. The frequency spectrum of receiving wave is obtained using Fast Fourier Transform (FFT), and peak frequency and centroid frequency are calculated. During the entire loading process, peak frequency fluctuates around 110[Formula: see text]kHz, but corresponding centroid frequency decreases obviously at the end stage of loading. According to multifractal theory, the multifractal spectrum of wavelet packet energy characteristics is calculated. The results show that wavelet packet energy distribution has obvious multifractal characteristics, and multifractal parameter [Formula: see text] presents downward trend before coal samples buckling failure. Based on damage process of the coal samples, the reason of change in [Formula: see text] value is related to damage degree of coal samples. This research is of great significance for understanding the deformation and failure process of coal samples using ultrasonic technology.

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Liu, Dong, Lulu Zhang, Juan Zhao, Qin Zhang, Yuzhi Song, and Qingtian Meng. "Quantum and quasiclassical dynamics of C(3P)+H2(1Σg+)→H(2S)+CH(2Π) Coriolis coupling effects and stereodynamics." Chinese Physics B 31, no. 4 (April 1, 2022): 043102. http://dx.doi.org/10.1088/1674-1056/ac3989.

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The dynamics of C + H2 → H + CH reaction is theoretically studied using the quasiclassical trajectory and quantum mechanical wave packet methods. The analysis of reaction probabilities, integral cross sections, and rate coefficients reveal the essential Coriolis coupling effects in the quantum mechanical wave packet calculations. The calculated polarization-dependent differential cross section, P(θr ) and P(ϕr ) show that the j ′ of product rotational angular momentum is not only aligned along the y axis and the direction of the vector x + z , but also strongly oriented along the positive y axis.

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Rahimi, Asghar, and Niloufar Seddighi. "Finite equal norm Parseval wavelet frames over prime fields." International Journal of Wavelets, Multiresolution and Information Processing 15, no. 04 (May 7, 2017): 1750040. http://dx.doi.org/10.1142/s0219691317500400.

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In the framework of wave packet analysis, finite wavelet systems are particular classes of finite wave packet systems. In this paper, using a scaling matrix on a permuted version of the discrete Fourier transform (DFT) of system generator, we derive a locally-scaled version of the DFT of system generator and obtain a finite equal-norm Parseval wavelet frame over prime fields. We also give a characterization of all multiplicative subgroups of the cyclic multiplicative group, for which the associated wavelet systems form frames. Finally, we present some concrete examples as applications of our results.

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Pereira, A. L. S., M. L. Lyra, F. A. B. F. de Moura, A. Ranciaro Neto, and W. S. Dias. "Nonlinear wave-packet dynamics resonantly driven by AC and DC fields." Communications in Nonlinear Science and Numerical Simulation 64 (November 2018): 89–97. http://dx.doi.org/10.1016/j.cnsns.2018.04.016.

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Mahan, Munera W., and M. J. Majid. "Time Evolution of the Position Operators in a Bilayer Graphene." NeuroQuantology 19, no. 12 (December 29, 2021): 19–29. http://dx.doi.org/10.14704/nq.2021.19.12.nq21192.

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In this work, the researchers mainly focus on the trembling motion which is known as Zitterbewegung in a bilayer grapheme. This is effectively achieved by means of the long-wave approximation. That is, the Heisenberg representation is ultimately employed in order to derive the analytical expression concerning the expectation value related to the position operator along the longitudinal and transversal orientation, which describes the motion concerning the electronic wave packet inside the bilayer graphene. Parameters’ numbers are considered to explicate the packet of Gaussian wave, including the polarization of initial pseudo-spin as well as the wave number of the initial carrier number along with the localized wave packet’s width along the longitudinal as well as transversal orientation. Consequently, the researchers show that the obvious oscillation in position operator can be effectively controlled not only by what is known as the initial parameters concerning the wave packet. Rather, it can mainly be controlled by selecting the localized quantum state’s components. Furthermore, the interference’s analysis between the conduction as well as valence bands concerning quantum states is really emphasized as the ability of what can be described as the transient’s emergence, or in a sense, aperiodic temporal oscillations concerning the average value of position operator in the bilayer graphene.

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Zhang, Xiaoyu, Liuyu Zhang, Laijun Liu, and Linsheng Huo. "Tension Monitoring of Wedge Connection Using Piezoceramic Transducers and Wavelet Packet Analysis Method." Sensors 20, no. 2 (January 8, 2020): 364. http://dx.doi.org/10.3390/s20020364.

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A steel strand is widely used in long span prestressed concrete bridges. The safety and stability of a steel strand are important issues during its operation period. A steel strand is usually subjected to various types of prestress loss which loosens the anchorage system, negatively impacting the stability of the structure and even leading to severe accidents. In this paper, the authors propose a wavelet packet analysis method to monitor the looseness of the wedge anchorage system by using stress wave-based active sensing. As a commonly used piezoceramic material, lead zirconate titanate (PZT) is employed with a strong piezoelectric effect. In the proposed active sensing approach, PZT patches are used as sensors and actuators to monitor the steel strand looseness. The anchorage system consists of the steel strand, wedges and barrel, which forms two different direct contact surfaces to monitor the tension force. PZT patches are pasted on the surface of each steel strand, corresponding wedge and barrel, respectively. Different combinations of PZTs are formed to monitor the anchoring state of the steel strand according to the position of the PZT patches. In this monitoring method of two contact surfaces, one PZT patch is used as an actuator to generate a stress wave and the other corresponding PZT patch is used as a sensor to detect the propagated waves through the wedge anchorage system. The function of these two PZTs were exchanged with the changing of transmission direction. The wavelet packet analysis method is utilized to analyze the transmitted signal between PZT patches through the steel strand anchorage system. Compared with the wavelet packet energy of received signals under different PZT combinations, it could be found that the wavelet packet energy increased with the increasing of anchorage system tightness. Therefore, the wavelet packet energy of received signal could be used to monitor the tightness of the steel strand during operation. Additionally, the wavelet packet energy of the received signals are different when the same PZT combination exchanges the energy transfer direction. With the comparison on the received signals of different combinations of PZTs, the optimal energy transfer path corresponding to different contact surfaces of the steel strand could be determined and the optimal experimental results are achieved.

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Hertzog, A., C. Souprayen, and A. Hauchecorne. "Observation and backward trajectory of an inertio-gravity wave in the lower stratosphere." Annales Geophysicae 19, no. 9 (September 30, 2001): 1141–55. http://dx.doi.org/10.5194/angeo-19-1141-2001.

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Abstract. A Doppler lidar observation of an inertio-gravity wave in the mid-latitude lower stratosphere is presented. The wave packet characteristics (vertical and horizontal wavenumbers, intrinsic and apparent frequencies) are inferred from the analysis of the hodograph of the horizontal wind fluctuations. Those parameters are used as initial conditions for the calculation of the wave packet trajectory backwards in time in the atmosphere. These calculations are realized by ray-tracing techniques, with background fields (wind and stability) provided by the European Center for Medium-Range Weather Forecasting analyses. Sensitivity tests are performed in order to estimate the robustness of the computed trajectory. It is argued that the generation of the wave has taken place in the upper troposphere, where evidence of large synoptic scale Rossby wave disturbances are found. Our results support the fact that geostrophic adjustment (and possibly shear instabilities) associated with such disturbances could be an effective mechanism for the generation of inertia-gravity waves in the mid-latitude.Key words. Meteorology and atmospheric dynamics, mesoscale meteorology, waves and tides, instruments and techniques

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Qiu Chenlin, 邱辰霖, and 程礼 Cheng Li. "Wavelet Packet Analysis in Plasma Acoustic Wave Diagnosis of Laser Shock Processing." APPLIED LASER 32, no. 1 (2012): 61–64. http://dx.doi.org/10.3788/al20123201.061.

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Braun, Markus, Constanze Sobotta, Regina Dürr, Horst Pulvermacher, and Stephan Malkmus. "Analysis of Wave Packet Motion in Frequency and Time Domain: Oxazine 1." Journal of Physical Chemistry A 110, no. 32 (August 2006): 9793–800. http://dx.doi.org/10.1021/jp057543l.

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Sjakste, J., A. G. Borisov, J. P. Gauyacq, and A. K. Kazansky. "Analysis of the population of continuum states in wave packet propagation calculations." Journal of Physics B: Atomic, Molecular and Optical Physics 37, no. 8 (April 2, 2004): 1593–603. http://dx.doi.org/10.1088/0953-4075/37/8/003.

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Lu, Jianfeng, Benedikt Wirth, and Haizhao Yang. "Combining 2D synchrosqueezed wave packet transform with optimization for crystal image analysis." Journal of the Mechanics and Physics of Solids 89 (April 2016): 194–210. http://dx.doi.org/10.1016/j.jmps.2016.01.002.

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Journal articles on the topic 'Wave-packet analysis'

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