scholarly journals Wave packet construction in three-dimensional quantum billiards: Visualizing the closed orbit, collapse and revival of wave packets in the cubical billiard

Pramana ◽  
2015 ◽  
Vol 86 (1) ◽  
pp. 31-48 ◽  
Author(s):  
MANINDER KAUR ◽  
BINDIYA ARORA ◽  
MAHMOOD MIAN
Keyword(s):  
Wave Packet ◽  
Wave Packets ◽  
Closed Orbit ◽  
Three Dimensional

Space-Time Recovery of Arbitrarily Shaped Wave-Packets by Means of Three Dimensional Imaging Technique

2004 ◽  
Vol 9 (3) ◽  
pp. 259-270 ◽  
Author(s):  
A. Matijošius ◽  
R. Piskarskas ◽  
E. Gaižauskas ◽  
A. Dubietis ◽  
P. Di Trapani
Keyword(s):  
Wave Packet ◽  
Imaging Technique ◽  
Wave Packets ◽  
Three Dimensional ◽  
Space Time ◽  
Time Transformation ◽  
Spectral Features ◽  
Three Dimensional Imaging ◽  
Light Pulses ◽  
Self Focusing

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.

scholarly journals The Stationary Frontal Wave Packet Spontaneously Generated in Mesoscale Dipoles

2008 ◽  
Vol 38 (1) ◽  
pp. 243-256 ◽  
Author(s):  
Álvaro Viúdez
Keyword(s):  
Wave Packet ◽  
Wave Packets ◽  
Plane Waves ◽  
Three Dimensional ◽  
Vertical Shear ◽  
Vertical Column ◽  
Vortical Structures ◽  
Frontal Wave ◽  
Fluid Particles ◽  
Balanced Flow

Abstract Three-dimensional numerical simulations of rotating, statically and inertially stable, mesoscale flows show that wave packets, with vertical velocity comparable to that of the balanced flow, can be spontaneously generated and amplified in the frontal part of translating vortical structures. These frontal wave packets remain stationary relative to the vortical structure (e.g., in the baroclinic dipole, tripole, and quadrupole) and are due to inertia–gravity oscillations, near the inertial frequency, experienced by the fluid particles as they decelerate when leaving the large speed regions. The ratio between the horizontal and vertical wavenumbers depends on the ratio between the horizontal and vertical shears of the background velocity. Theoretical solutions of plane waves with varying wavenumbers in background flow confirm these results. Using the material description of the fields it is shown that, among the particles simultaneously located in the vertical column in the dipole’s center, the first ones to experience the inertia–gravity oscillations are those in the upper layer, in the region of the maximum vertical shear. The wave packet propagates afterward to the fluid particles located below.

Three-dimensional electromagnetic strong turbulence. II. Wave packet collapse and structure of wave packets during strong turbulence

2011 ◽  
Vol 18 (7) ◽  
pp. 072302 ◽  
Author(s):  
D. B. Graham ◽  
P. A. Robinson ◽  
Iver H. Cairns ◽  
O. Skjaeraasen
Keyword(s):  
Wave Packet ◽  
Wave Packets ◽  
Three Dimensional ◽  
Strong Turbulence

The Spectrum Segmentation Algorithm of Multimode Vibration Signal Based on Spectral Clustering

2011 ◽  
Vol 121-126 ◽  
pp. 2372-2376
Author(s):  
Dan Dan Wang ◽  
Yu Zhou ◽  
Qing Wei Ye ◽  
Xiao Dong Wang
Keyword(s):  
Wave Packet ◽  
Frequency Domain ◽  
Spectral Clustering ◽  
Clustering Algorithm ◽  
Wave Packets ◽  
Vibration Signal ◽  
Segmentation Algorithm ◽  
Frequency Curve ◽  
Macroscopic Observation ◽  
Spectral Clustering Algorithm

The mode peaks in frequency domain of vibration signal are strongly interfered by strong noise, causing the inaccuracy mode parameters. According to this situation, this paper comes up with the thought of mode-peak segmentation based on the spectral clustering algorithm. First, according to the concept of wave packet, the amplitude-frequency of vibration signal is divided into wave packets. Taking each wave packet as a sample of clustering algorithm, the spectral clustering algorithm is used to classify these wave packets. The amplitude-frequency curve of a mode peak becomes a big wave packet in macroscopic. The experiment to simulation signals indicates that this spectral clustering algorithm could accord with the macroscopic observation of mode segmentation effectively, and has outstanding performance especially in strong noise.

Global three-dimensional optimal disturbances in the Blasius boundary-layer flow using time-steppers

2010 ◽  
Vol 650 ◽  
pp. 181-214 ◽  
Author(s):  
ANTONIOS MONOKROUSOS ◽  
ESPEN ÅKERVIK ◽  
LUCA BRANDT ◽  
DAN S. HENNINGSON
Keyword(s):  
Boundary Layer ◽  
Boundary Layer Flow ◽  
Wave Packets ◽  
Three Dimensional ◽  
Computational Domain ◽  
Initial Condition ◽  
Oblique Wave ◽  
Layer Flow ◽  
Optimal Disturbances ◽  
Matrix Free

The global linear stability of the flat-plate boundary-layer flow to three-dimensional disturbances is studied by means of an optimization technique. We consider both the optimal initial condition leading to the largest growth at finite times and the optimal time-periodic forcing leading to the largest asymptotic response. Both optimization problems are solved using a Lagrange multiplier technique, where the objective function is the kinetic energy of the flow perturbations and the constraints involve the linearized Navier–Stokes equations. The approach proposed here is particularly suited to examine convectively unstable flows, where single global eigenmodes of the system do not capture the downstream growth of the disturbances. In addition, the use of matrix-free methods enables us to extend the present framework to any geometrical configuration. The optimal initial condition for spanwise wavelengths of the order of the boundary-layer thickness are finite-length streamwise vortices exploiting the lift-up mechanism to create streaks. For long spanwise wavelengths, it is the Orr mechanism combined with the amplification of oblique wave packets that is responsible for the disturbance growth. This mechanism is dominant for the long computational domain and thus for the relatively high Reynolds number considered here. Three-dimensional localized optimal initial conditions are also computed and the corresponding wave packets examined. For short optimization times, the optimal disturbances consist of streaky structures propagating and elongating in the downstream direction without significant spreading in the lateral direction. For long optimization times, we find the optimal disturbances with the largest energy amplification. These are wave packets of Tollmien–Schlichting waves with low streamwise propagation speed and faster spreading in the spanwise direction. The pseudo-spectrum of the system for real frequencies is also computed with matrix-free methods. The spatial structure of the optimal forcing is similar to that of the optimal initial condition, and the largest response to forcing is also associated with the Orr/oblique wave mechanism, however less so than in the case of the optimal initial condition. The lift-up mechanism is most efficient at zero frequency and degrades slowly for increasing frequencies. The response to localized upstream forcing is also discussed.

scholarly journals Spin-Orbit Entanglement in Time Evolution of Radial Wave Packets in Hydrogenic Systems

2004 ◽  
Vol 11 (04) ◽  
pp. 401-409
Author(s):  
Marcin Turek ◽  
Piotr Rozmej
Keyword(s):  
Wave Packet ◽  
Time Evolution ◽  
Time Scale ◽  
Degrees Of Freedom ◽  
Wave Packets ◽  
Characteristic Time Scale ◽  
Radial Wave ◽  
Mean Values ◽  
Breathing Motion ◽  
Wave Packet Revival

Time evolution of radial wave packets built from the eigenstates of Dirac equation for a hydrogenic system is considered. Radial wave packets are constructed from the states of different n quantum numbers and the same lowest angular momentum. In general they exhibit a kind of breathing motion with dispersion and (partial) revivals. Calculations show that for some particular preparations of the wave packet one can observe interesting effects in spin motion, coming from inherent entanglement of spin and orbital degrees of freedom. These effects manifest themselves through some oscillations in the mean values of spin operators and through changes of spatial probability density carried by upper and lower components of the wave function. It is also shown that the characteristic time scale of predicted effects (called T ls ) is much smaller for radial wave packets than in other cases, reaching values comparable to (or even less than) the time scale for the wave packet revival.

scholarly journals ACCELERATION OF PARTICLES BY THE FIELDS OF WAVE PACKETS

2019 ◽  
pp. 43-46
Author(s):  
V.А. Buts ◽  
V.V. Kuzmin ◽  
A.P. Tolstoluzhsky
Keyword(s):  
Wave Packet ◽  
Wave Packets ◽  
Dynamic Chaos ◽  
Acceleration Of Particles ◽  
Nonlinear Resonances ◽  
Dynamics Of Particles

The dynamics of particles in the field of a wave packet excited in a plasma is considered. The conditions are found under which such dynamics is regular, and when it becomes chaotic. It was found that the well-known (phenomenological) criterion for the emergence of dynamic chaos − the criterion for overlapping Chirikov nonlinear resonances − requires careful use.

Excitation Of Localized Wave Packet In 3d Supersonic Boundary Layer

2017 ◽  
Vol 12 (1) ◽  
pp. 57-65
Author(s):  
Alex Yatskih ◽  
Marina Rumenskikh ◽  
Yuri Yermolaev ◽  
Aleksandr Kosinov ◽  
Nikolay Semionov ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Wave Packet ◽  
Wave Packets ◽  
Leading Edge ◽  
Supersonic Boundary Layer ◽  
Swept Wing ◽  
Sweep Angle ◽  
Asymmetric Shape ◽  
Pulse Electric ◽  
Pulse Electric Discharge

The results of experimental study of excitation of localized in time and space controlled disturbances (wave packets) in a supersonic swept-wing boundary layer are presented. The experiments were performed at Mach number M = 2 on the model of wing with a lenticular profile and a 40 degrees sweep angle of the leading edge at zero angle of attack. Wave packets were generated by a pulse electric discharge on the surface of the model. A structure of controlled wave packet was studied. It was found that the wave packet has an asymmetric shape. Comparison with the case of twodimensional boundary layer was done.

Quantum Spectra and Classical Orbits in Nano-Microstructure

2010 ◽  
Vol 160-162 ◽  
pp. 625-629 ◽  
Author(s):  
Jun Lu ◽  
Xue Mei Wang
Keyword(s):  
Closed Orbit ◽  
Three Dimensional ◽  
Spectrum Function ◽  
Molecular Reaction ◽  
Classical Quantum ◽  
Orbit Theory ◽  
Quantum Correspondence ◽  
New Evidence ◽  
Quantum Spectrum ◽  
Classical Orbits

A kind of new classical-quantum correspondence principle is proposed using the idea of closed-orbit theory. The quantum spectrum function is introduced by means of the eigenvalues and the eigenfunctions in the system of one-dimensional nano-microstructure. The Fourier transformation of the quantum spectrum function is found corresponding with the classical orbits in the system. These results give new evidence about the classical-quantum correspondence. All the methods and results can be used in a lot of other systems, including some two-dimensional and three-dimensional systems. The researches about these systems are very important in the field of applied science, for example, molecular reaction dynamics and quantum information.

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