scholarly journals Collective modes in three-dimensional magnonic vortex crystals

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Max Hänze ◽  
Christian F. Adolff ◽  
Benedikt Schulte ◽  
Jan Möller ◽  
Markus Weigand ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Collective Modes

scholarly journals Collective Modes in the Quantum Lattice or Three-Dimensional XY Model. I

1981 ◽  
Vol 66 (3) ◽  
pp. 861-878 ◽  
Author(s):  
T. Aoki ◽  
S. Homma ◽  
H. Nakano
Keyword(s):  
Three Dimensional ◽  
Collective Modes ◽  
Xy Model ◽  
Quantum Lattice

scholarly journals Collective modes in multi-Weyl semimetals

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Seongjin Ahn ◽  
E. H. Hwang ◽  
Hongki Min
Keyword(s):  
Three Dimensional ◽  
Critical Density ◽  
Collective Modes ◽  
Band Model ◽  
Interband Transitions ◽  
Linear Dispersion ◽  
Long Wavelength ◽  
Band Dispersion ◽  
Weyl Semimetals ◽  
Non Linear

Abstract We investigate collective modes in three dimensional (3D) gapless multi-Weyl semimetals with anisotropic energy band dispersions (i.e., "Equation missing" with a positive integer J). For comparison, we also consider the gapless semimetals with the isotropic band dispersions (i.e. E ~ k J ). We calculate analytically long-wavelength plasma frequencies incorporating interband transitions and chiral properties of carriers. For both the isotropic and anisotropic cases, we find that interband transitions and chirality lead to the depolarization shift of plasma frequencies. For the isotropic parabolic band dispersion the long-wavelength plasmons do not decay via Landau damping, while for the higher-order band dispersions the long-wavelength plasmons experience damping below a critical density. For systems with the anisotropic dispersion the density dependence of the long-wavelength plasma frequency along the direction of non-linear dispersion behaves like that of the isotropic linear band model, while along the direction of linear dispersion it behaves like that of the isotropic non-linear model. Plasmons along both directions remain undamped over a broad range of densities due to the chirality induced depolarization shift. Our results provide a comprehensive picture of how band dispersion and chirality affect plasmon behaviors in 3D gapless chiral systems with the arbitrary band dispersion.

MAGNETOPLASMA OSCILLATIONS OF A TWO-DIMENSIONAL, TWO-COMPONENT PLASMA

1996 ◽  
Vol 10 (16) ◽  
pp. 737-744
Author(s):  
NGUYEN QUOC KHANH
Keyword(s):  
Random Phase Approximation ◽  
Random Phase ◽  
Three Dimensional ◽  
Collective Modes ◽  
Two Dimensional ◽  
Long Wavelength ◽  
Effective Masses ◽  
Two Component ◽  
Component Plasma ◽  
The Individual

We investigate the magnetoplasma excitations in a system comprised of two parallel two-dimensional conducting layers separated by a distance 2d>0. The individual layers are assumed to have, in general, different effective masses, particle densities and charges. The dispersion equations are derived quantum mechanically within the random phase approximation and the spectrum of the long wavelength collective modes is calculated. We also investigate the mutual phase of two-dimensional magnetoplasma oscillations and show that this mutual phase is similar to that in the three-dimensional case and does not depend on the interlayer distance.

scholarly journals Collective Modes in Quantum Lattice or Three-Dimensional XY Model. II

1982 ◽  
Vol 67 (6) ◽  
pp. 1724-1739
Author(s):  
T. Aoki ◽  
S. Homma ◽  
H. Nakano
Keyword(s):  
Three Dimensional ◽  
Collective Modes ◽  
Xy Model ◽  
Quantum Lattice

Density waves in disk galaxies

1967 ◽  
Vol 31 ◽  
pp. 313-317 ◽  
Author(s):  
C. C. Lin ◽  
F. H. Shu
Keyword(s):  
Mathematical Analysis ◽  
Spiral Structure ◽  
Stellar System ◽  
Collective Modes ◽  
Disk Galaxies ◽  
Spiral Pattern ◽  
Density Waves ◽  
The Galaxy ◽  
Detailed Mathematical Analysis

Density waves in the nature of those proposed by B. Lindblad are described by detailed mathematical analysis of collective modes in a disk-like stellar system. The treatment is centered around a hypothesis of quasi-stationary spiral structure. We examine (a) the mechanism for the maintenance of this spiral pattern, and (b) its consequences on the observable features of the galaxy.

The orbit of Pluto over a long interval of time

1966 ◽  
Vol 25 ◽  
pp. 227-229 ◽  
Author(s):  
D. Brouwer
Keyword(s):  
Periodic Orbit ◽  
Numerical Integration ◽  
Restricted Problem ◽  
Three Dimensional ◽  
The Third ◽  
Circular Restricted Problem ◽  
Resonance Relation

The paper presents a summary of the results obtained by C. J. Cohen and E. C. Hubbard, who established by numerical integration that a resonance relation exists between the orbits of Neptune and Pluto. The problem may be explored further by approximating the motion of Pluto by that of a particle with negligible mass in the three-dimensional (circular) restricted problem. The mass of Pluto and the eccentricity of Neptune's orbit are ignored in this approximation. Significant features of the problem appear to be the presence of two critical arguments and the possibility that the orbit may be related to a periodic orbit of the third kind.

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