Spectra and bound states of the energy operator of two-magnon systems in a non-Heisenberg ferromagnet with spin one and nearest-neighbor coupling

2000 ◽  
Vol 125 (2) ◽  
pp. 1539-1551 ◽  
Author(s):  
S. M. Tashpulatov
Keyword(s):  
Bound States ◽  
Nearest Neighbor ◽  
Energy Operator ◽  
Heisenberg Ferromagnet ◽  
Nearest Neighbor Coupling

SPECTRA AND BOUND STATES OF THE ENERGY OPERATOR OF TWO-MAGNON SYSTEM IN A NON-HEISENBERG FERROMAGNET WITH SPIN S = 3/2 AND NEAREST-NEIGHBOR INTERACTIONS

2009 ◽  
Vol 12 (01) ◽  
pp. 117-133
Author(s):  
S. M. TASHPULATOV
Keyword(s):  
Energy Spectrum ◽  
Bound States ◽  
Nearest Neighbor ◽  
Energy Operator ◽  
Heisenberg Ferromagnet ◽  
Dimensional Lattice ◽  
Quasi Momentum ◽  
Hamiltonian Parameters

We consider a two-magnon systems in an ν-dimensional isotropic non-Heisenberg ferromagnet with spin value S = 3/2 and nearest-neighbor interactions. Spectrum and bound states (BS) of the system for all values of full quasi-momentum Λ, and for arbitrary value of lattice dimensionality ν, and for all values of Hamiltonian parameters are investigated. We show that (i) for arbitrary ν ≥ 2 and for full quasi-momentum in the form Λ = (Λ1; Λ2; … ;Λν) = (Λ0;Λ0; …; Λ0) the change of energy spectrum of the system is similar to that observed in the case of ν = 1. In this case the operator [Formula: see text] with J + J1 - 23J2 ≠ 0 has only one additional BS. (ii) The energy z of this additional BS is degenerate ν - 1 times. (iii) If Λ ≠ (Λ0;Λ0;…;Λ0), we show the existence no more 2ν + 1 bound states in the system in ν-dimensional lattice.

scholarly journals THOULESS NUMBER AND SPIN DIFFUSION IN QUANTUM HEISENBERG FERROMAGNETS

1993 ◽  
Vol 07 (27) ◽  
pp. 1747-1759 ◽  
Author(s):  
PETER KOPIETZ
Keyword(s):  
Spin Diffusion ◽  
Nearest Neighbor ◽  
Arbitrary Dimension ◽  
Quantum Spin ◽  
Spin Systems ◽  
Heisenberg Ferromagnet ◽  
Electronic Systems ◽  
Dimensionless Frequency ◽  
Spin Models ◽  
Quantum Spin Models

Using an analogy between the conductivity tensor of electronic systems and the spin stiffness tensor of spin systems, we introduce the concept of the Thouless number g0 and the dimensionless frequency-dependent conductance g(ω) for quantum spin models. It is shown that spin diffusion implies the vanishing of the Drude peak of g(ω), and that the spin diffusion coefficient Ds is proportional to g0. We develop a new method based the Thouless number to calculate D s , and present results for D s in the nearest-neighbor quantum Heisenberg ferromagnet at infinite temperatures for arbitrary dimension d and spin S.

Engineering Nearest Neighbor Coupling in Huygens Metasurfaces

2021 ◽  
Author(s):  
Isaac O. Oguntoye ◽  
Siddharth Padmanabha ◽  
Brittany Simone ◽  
Adam Ollanik ◽  
Matthew D. Escarra
Keyword(s):  
Nearest Neighbor ◽  
Nearest Neighbor Coupling

NONLOCAL SYNCHRONIZATION IN NEAREST NEIGHBOR COUPLED OSCILLATORS

2002 ◽  
Vol 12 (12) ◽  
pp. 2945-2955 ◽  
Author(s):  
HASSAN F. EL-NASHAR ◽  
AHMED S. ELGAZZAR ◽  
HILDA A. CERDEIRA
Keyword(s):  
Coupled Oscillators ◽  
Nearest Neighbor ◽  
Power Spectra ◽  
Direct Coupling ◽  
Frequency Synchronization ◽  
Nearest Neighbor Coupling

We investigate a system of nearest neighbor coupled oscillators. We show that the nonlocal frequency synchronization, that might appear in such a system, occurs as a consequence of the nearest neighbor coupling. The power spectra of nonadjacent oscillators show that there is no complete coincidence between all frequency peaks of the oscillators in the nonlocal cluster, while the peaks for neighboring oscillators approximately coincide even if they are not yet in a cluster. It is shown that nonadjacent oscillators closer in frequencies, share slow modes with their adjacent oscillators which are neighbors in space. It is also shown that when a direct coupling between non-neighbors oscillators is introduced explicitly, the peaks of the spectra of the frequencies of those non-neighbors coincide.

scholarly journals Spreading of perturbations in myosin group kinetics along actin filaments

2019 ◽  
Vol 116 (35) ◽  
pp. 17336-17344 ◽  
Author(s):  
Zsombor Balassy ◽  
Anne-Marie Lauzon ◽  
Lennart Hilbert
Keyword(s):  
Actin Filament ◽  
Actin Filaments ◽  
Nearest Neighbor ◽  
Global Changes ◽  
Chain Model ◽  
Mechanical Coupling ◽  
In Vitro Motility ◽  
Local Perturbations ◽  
Nearest Neighbor Coupling

Global changes in the state of spatially distributed systems can often be traced back to perturbations that arise locally. Whether such local perturbations grow into global changes depends on the system geometry and the spatial spreading of these perturbations. Here, we investigate how different spreading behaviors of local perturbations determine their global impact in 1-dimensional systems of different size. Specifically, we assessed sliding arrest events in in vitro motility assays where myosins propel actin, and simulated the underlying mechanochemistry of myosins that bind along the actin filament. We observed spontaneous sliding arrest events that occurred more frequently for shorter actin filaments. This observation could be explained by spontaneous local arrest of myosin kinetics that stabilizes once it spreads throughout an entire actin filament. When we introduced intermediate concentrations of the actin cross-linker filamin, longer actin was arrested more frequently. This observation was reproduced by simulations where filamin binding induces persistent local arrest of myosin kinetics, which subsequently spreads throughout the actin filament. A spin chain model with nearest-neighbor coupling reproduced key features of our experiments and simulations, thus extending to other linear systems with nearest-neighbor coupling the following conclusions: 1) perturbations that are persistent only once they spread throughout the system are more effective in smaller systems, and 2) perturbations that are persistent upon their establishment are more effective in larger systems. Beyond these general conclusions, our work also provides a theoretical model of collective myosin kinetics with a finite range of mechanical coupling along the actin filament.

Effect of Biquadratic Exchange on Two Magnon States of Heisenberg Ferromagnets: Other Neighbor Exchange

1975 ◽  
Vol 53 (6) ◽  
pp. 637-647 ◽  
Author(s):  
D. A. Pink ◽  
Vijay Sachdeva
Keyword(s):  
Ground State ◽  
Nearest Neighbor ◽  
Ferromagnetic State ◽  
Localized States ◽  
Heisenberg Ferromagnet ◽  
Green Functions ◽  
Localized Modes ◽  
One Dimensional ◽  
Localized State ◽  
Biquadratic Exchange

We have investigated the two magnon localized states of a one dimensional Heisenberg ferromagnet the Hamiltonian of which is made up of nearest neighbor and next nearest neighbor isotropic bilinear and biquadratic exchange terms, and a single ion anisotropy term. We have restricted our choice of parameters so that the ground state at T = 0 is the fully aligned ferromagnetic state and we have used the thermodynamic Green functions where the averages have been evaluated in the ground state so that our results are good for [Formula: see text]. We have evaluated the probabilities of finding two spin deviations a distance n apart when the system is in a localized state described by total wave vector q. We have (a) compared the effects of ferromagnetic and antiferromagnetic next nearest neighbor exchange, (b) found that localized modes can lie below or above the two free magnon band depending upon the sign and magnitude of the biquadratic exchange, (c) found that in certain cases two spin deviations appear to behave like objects interacting only via a soft core, and (d) found that modes can have a large single ion component when the single ion anisotropy is zero.

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