scholarly journals Control of the coupling strength and linewidth of a cavity magnon-polariton

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Isabella Boventer ◽  
Christine Dörflinger ◽  
Tim Wolz ◽  
Rair Macêdo ◽  
Romain Lebrun ◽  
...  
Keyword(s):  
Coupling Strength

scholarly journals Dipole radiation and beyond from axion stars in electromagnetic fields

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Mustafa A. Amin ◽  
Andrew J. Long ◽  
Zong-Gang Mou ◽  
Paul M. Saffin
Keyword(s):  
Electromagnetic Fields ◽  
Parametric Resonance ◽  
Coupling Strength ◽  
Coupling Parameter ◽  
Strong Dependence ◽  
Dipole Radiation ◽  
Large Coupling ◽  
External Electromagnetic Fields ◽  
Order Of Magnitude ◽  
Dimensionless Coupling

Abstract We investigate the production of photons from coherently oscillating, spatially localized clumps of axionic fields (oscillons and axion stars) in the presence of external electromagnetic fields. We delineate different qualitative behaviour of the photon luminosity in terms of an effective dimensionless coupling parameter constructed out of the axion-photon coupling, and field amplitude, oscillation frequency and radius of the axion star. For small values of this dimensionless coupling, we provide a general analytic formula for the dipole radiation field and the photon luminosity per solid angle, including a strong dependence on the radius of the configuration. For moderate to large coupling, we report on a non-monotonic behavior of the luminosity with the coupling strength in the presence of external magnetic fields. After an initial rise in luminosity with the coupling strength, we see a suppression (by an order of magnitude or more compared to the dipole radiation approximation) at moderately large coupling. At sufficiently large coupling, we find a transition to a regime of exponential growth of the luminosity due to parametric resonance. We carry out 3+1 dimensional lattice simulations of axion electrodynamics, at small and large coupling, including non-perturbative effects of parametric resonance as well as backreaction effects when necessary. We also discuss medium (plasma) effects that lead to resonant axion to photon conversion, relevance of the coherence of the soliton, and implications of our results in astrophysical and cosmological settings.

Complex projection synchronization of fractional order uncertain complex-valued networks with time-varying coupling

2019 ◽  
Vol 33 (29) ◽  
pp. 1950351 ◽  
Author(s):  
Dawei Ding ◽  
Xiaolei Yao ◽  
Hongwei Zhang
Keyword(s):  
Fractional Order ◽  
Coupling Strength ◽  
Dynamic Networks ◽  
Sufficient Conditions ◽  
Feedback Gain ◽  
Time Varying ◽  
Order Complex ◽  
Unknown Parameters ◽  
Synchronization Problem ◽  
Complex Valued

In this paper, the complex projection synchronization problem of fractional complex-valued dynamic networks is investigated. Considering the time-varying coupling and unknown parameters of the fractional order complex network, several decentralized adaptive strategies are designed to adjust the coupling strength and controller feedback gain in order to investigate the complex projection synchronization problem of the system. Moreover, based on the designed identification law, the uncertain parameters in the network can be estimated. Using adaptive law which balances the time-varying coupling strength and the feedback gain of the controller, some sufficient conditions are obtained for the complex projection synchronization of complex networks. Finally, numerical simulation examples are provided to illustrate the efficiency of the complex projection synchronization strategies of the fractional order complex dynamic networks.

TRANSITION FREQUENCY OF STRONG-COUPLING IMPURITY BOUND POLARON IN AN ASYMMETRIC QUANTUM DOT

2012 ◽  
Vol 11 (03) ◽  
pp. 1250026 ◽  
Author(s):  
CHENG-SHUN WANG ◽  
YU-FANG CHEN ◽  
JING-JIN XIAO
Keyword(s):  
Excited State ◽  
Coupling Strength ◽  
State Energy ◽  
Transition Frequency ◽  
Phonon Coupling ◽  
Excited State Energy ◽  
Bound Polaron ◽  
Asymmetric Quantum Dot ◽  
Asymmetric Quantum ◽  
Electron Phonon Coupling

Properties of the excited state of strong-coupling impurity bound polaron in an asymmetric quantum dot are studied by using linear combination operator and unitary transformation methods. The first internal excited state energy, the excitation energy and the transition frequency between the first internal excited and the ground states of the impurity bound polaron as functions of the transverse and the longitudinal effective confinement lengths of the dot, the electron–phonon coupling strength and the Coulomb bound potential were derived. Our numerical results show that they will increase with decreasing the effective confinement lengths, due to interesting quantum size confining effects. But they are an increasing functions of the Coulomb bound potential. The first internal excited state energy is a decreasing function of the electron–phonon coupling strength whereas the transition frequency and the excitation energy are an increasing one of the electron–phonon coupling strength.

Magnetic-Field Dependence of Raman Coupling Strength in Ultracold 40 K Atomic Fermi Gas

2016 ◽  
Vol 33 (3) ◽  
pp. 033401
Author(s):  
Liang-Hui Huang ◽  
Peng-Jun Wang ◽  
Zeng-Ming Meng ◽  
Peng Peng ◽  
Liang-Chao Chen ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Dependence ◽  
Coupling Strength ◽  
Magnetic Field Dependence ◽  
Fermi Gas ◽  
Atomic Fermi Gas

CELLULAR NEURAL NETWORKS CAN MIMIC SMALL-WORLD NETWORKS

1999 ◽  
Vol 09 (10) ◽  
pp. 2105-2126 ◽  
Author(s):  
TAO YANG ◽  
LEON O. CHUA
Keyword(s):  
Neural Networks ◽  
Coupling Strength ◽  
Initial Conditions ◽  
Computing Time ◽  
Small World ◽  
Cellular Neural Networks ◽  
Clustering Coefficient ◽  
High Survival ◽  
Game Of Life ◽  
Hole Detection

Small-world phenomenon can occur in coupled dynamical systems which are highly clustered at a local level and yet strongly coupled at the global level. We show that cellular neural networks (CNN's) can exhibit "small-world phenomenon". We generalize the "characteristic path length" from previous works on "small-world phenomenon" into a "characteristic coupling strength" for measuring the average coupling strength of the outputs of CNN's. We also provide a simplified algorithm for calculating the "characteristic coupling strength" with a reasonable amount of computing time. We define a "clustering coefficient" and show how it can be calculated by a horizontal "hole detection" CNN, followed by a vertical "hole detection" CNN. Evolutions of the game-of-life CNN with different initial conditions are used to illustrate the emergence of a "small-world phenomenon". Our results show that the well-known game-of-life CNN is not a small-world network. However, generalized CNN life games whose individuals have strong mobility and high survival rate can exhibit small-world phenomenon in a robust way. Our simulations confirm the conjecture that a population with a strong mobility is more likely to qualify as a small world. CNN games whose individuals have weak mobility can also exhibit a small-world phenomenon under a proper choice of initial conditions. However, the resulting small worlds depend strongly on the initial conditions, and are therefore not robust.

The role of the spin-orbit coupling strength in the MO effects of magnetic insulators

2001 ◽  
Vol 37 (4) ◽  
pp. 2411-2413 ◽  
Author(s):  
You Xu ◽  
Jiehui Yang ◽  
Xijuan Zhang ◽  
Fang Zhang ◽  
M. Guillot
Keyword(s):  
Coupling Strength ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Magnetic Insulators

SUPPRESSING SPIRAL WAVES IN EXCITABLE MEDIA VIA UNIDIRECTIONAL COUPLING

2008 ◽  
Vol 22 (24) ◽  
pp. 4153-4161 ◽  
Author(s):  
YU QIAN ◽  
YU XUE ◽  
GUANG-ZHI CHEN
Keyword(s):  
Co Oxidation ◽  
Power Law ◽  
Coupling Strength ◽  
Control Method ◽  
Spiral Waves ◽  
Coupling Method ◽  
Excitable Media ◽  
Catalytic Co Oxidation ◽  
Unidirectional Coupling ◽  
High Control

A unidirectional coupling method to successfully suppress spiral waves in excitable media is proposed. It is shown that this control method has high control efficiency and is robust. It adapts to control of spiral waves for catalytic CO oxidation on platinum as well as for the FHN model. The power law n ~ c-k of control time steps n versus the coupling strength c for different models has been obtained.

GENERALIZED SYNCHRONIZATION, FREQUENCY-LOCKING AND PHASE-LOCKING OF COUPLED SINE CIRCLE MAPS

2001 ◽  
Vol 11 (08) ◽  
pp. 2245-2253
Author(s):  
WEN-XIN QIN
Keyword(s):  
Dynamical Systems ◽  
Invariant Manifold ◽  
Coupling Strength ◽  
Phase Locking ◽  
Coupled System ◽  
Generalized Synchronization ◽  
Frequency Locking ◽  
Local Systems ◽  
Circle Maps ◽  
The Individual

Applying invariant manifold theorem, we study the existence of generalized synchronization of a coupled system, with local systems being different sine circle maps. We specify a range of parameters for which the coupled system achieves generalized synchronization. We also investigate the relation between generalized synchronization, predictability and equivalence of dynamical systems. If the parameters are restricted in the specified range, then all the subsystems are topologically equivalent, and each subsystem is predictable from any other subsystem. Moreover, these subsystems are frequency locked even if the frequencies are greatly different in the absence of coupling. If the local systems are identical without coupling, then the widths of the phase-locked intervals of the coupled system are the same as those of the individual map and are independent of the coupling strength.

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