scholarly journals Parameterization of stochastic multiscale triads

2016 ◽  
Vol 23 (6) ◽  
pp. 435-445 ◽  
Author(s):  
Jeroen Wouters ◽  
Stamen Iankov Dolaptchiev ◽  
Valerio Lucarini ◽  
Ulrich Achatz
Keyword(s):  
Model Reduction ◽  
Weak Coupling ◽  
Degrees Of Freedom ◽  
Coupling Model ◽  
Linear Response Theory ◽  
Coupling Method ◽  
Test Cases ◽  
Weakly Coupled ◽  
Weak Coupling Method ◽  
Markovian System

Abstract. We discuss applications of a recently developed method for model reduction based on linear response theory of weakly coupled dynamical systems. We apply the weak coupling method to simple stochastic differential equations with slow and fast degrees of freedom. The weak coupling model reduction method results in general in a non-Markovian system; we therefore discuss the Markovianization of the system to allow for straightforward numerical integration. We compare the applied method to the equations obtained through homogenization in the limit of large timescale separation between slow and fast degrees of freedom. We numerically compare the ensemble spread from a fixed initial condition, correlation functions and exit times from a domain. The weak coupling method gives more accurate results in all test cases, albeit with a higher numerical cost.

scholarly journals Parametrization of stochastic multiscale triads

2016 ◽  
Author(s):  
Jeroen Wouters ◽  
Stamen I. Dolaptchiev ◽  
Valerio Lucarini ◽  
Ulrich Achatz
Keyword(s):  
Model Reduction ◽  
Weak Coupling ◽  
Degrees Of Freedom ◽  
Coupling Model ◽  
Linear Response Theory ◽  
Coupling Method ◽  
Scale Separation ◽  
Time Scale Separation ◽  
Weakly Coupled ◽  
Weak Coupling Method

Abstract. We discuss applications of a recently developed method for model reduction based on linear response theory of weakly coupled dynamical systems. We apply the weak coupling method to simple stochastic differential equations with slow and fast degrees of freedom. The weak coupling model reduction method results in general in a non-Markovian system, we therefore discuss the Markovianization of the system to allow for straightforward numerical integration. We compare the applied method to the equations obtained through homogenization in the limit of large time scale separation between slow and fast degrees of freedom. We numerically compare the ensemble spread from a fixed initial condition, correlation functions and exit times from a domain. The weak coupling method gives more accurate results in all test cases, albeit with a higher numerical cost.

EXPERIMENTAL TRACKING OF UNSTABLE ORBITS IN DRIVEN DIODE RESONATOR BY WEAK COUPLING

1996 ◽  
Vol 06 (04) ◽  
pp. 769-774 ◽  
Author(s):  
JONG CHEOL SHIN ◽  
SOOK-IL KWUN ◽  
YOUNGTAE KIM
Keyword(s):  
Feedback Control ◽  
Weak Coupling ◽  
Control Parameter ◽  
Chaotic Regime ◽  
Coupling Method ◽  
Generic Properties ◽  
Wide Range ◽  
Resonator System ◽  
Weak Coupling Method

The weak coupling method is demonstrated to stabilize and track the unstable orbits in the diode resonator system. Continuous tracking of the unstable orbits could be achieved over a wide range from the periodic down to the deep chaotic regime as the control parameter is varied continuously without changing the feedback control parameter. During the tracking of unstable orbits, hysteresis as well as switching of the attractors are observed and these are supposed to be the generic properties of continuous tracking.

A weak coupling method between the dynamics code HOST and the 3D unsteady Euler code WAVES

2001 ◽  
Vol 5 (6) ◽  
pp. 397-408 ◽  
Author(s):  
Gaëlle Servera ◽  
Philippe Beaumier ◽  
Michel Costes
Keyword(s):  
Weak Coupling ◽  
Coupling Method ◽  
Weak Coupling Method

The investigation on anomalous isotope effect coefficient of LaSrCuO superconductor

2019 ◽  
Vol 33 (31) ◽  
pp. 1950379
Author(s):  
P. Mycharoen ◽  
P. Udomsamuthirun
Keyword(s):  
Experimental Data ◽  
Critical Temperature ◽  
Temperature Dependence ◽  
Isotope Effect ◽  
Weak Coupling ◽  
Numerical Results ◽  
Coupling Method ◽  
Density Of State ◽  
Van Hove Singularity ◽  
Weak Coupling Method

In this research, the anomalous isotope effect coefficient of LaSrCuO superconductor was investigated in the weak-coupling method. The constant and van Hove singularity density of state, pseudogap, and the form of pseudogap temperature dependence on critical temperature are included in our calculation. Finally, the numerical results are shown in comparison with the experimental data of LaSrCuO superconductor. We found that the van Hove singularity density of state and the inversely relation of pseudogap temperature and critical temperature can fit well with the anomalous isotope effect coefficient data of LaSrCuO superconductor.

scholarly journals Scrambling in Yang-Mills

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Robert de Mello Koch ◽  
Eunice Gandote ◽  
Augustine Larweh Mahu
Keyword(s):  
Relaxation Time ◽  
Weak Coupling ◽  
Degrees Of Freedom ◽  
Yang Mills ◽  
Hooft Coupling ◽  
Dilatation Operator ◽  
Super Yang Mills Theory

Abstract Acting on operators with a bare dimension ∆ ∼ N2 the dilatation operator of U(N) $$ \mathcal{N} $$ N = 4 super Yang-Mills theory defines a 2-local Hamiltonian acting on a graph. Degrees of freedom are associated with the vertices of the graph while edges correspond to terms in the Hamiltonian. The graph has p ∼ N vertices. Using this Hamiltonian, we study scrambling and equilibration in the large N Yang-Mills theory. We characterize the typical graph and thus the typical Hamiltonian. For the typical graph, the dynamics leads to scrambling in a time consistent with the fast scrambling conjecture. Further, the system exhibits a notion of equilibration with a relaxation time, at weak coupling, given by t ∼ $$ \frac{\rho }{\lambda } $$ ρ λ with λ the ’t Hooft coupling.

Low-lying Negative-parity Levels of 17N and 18N

1984 ◽  
Vol 37 (1) ◽  
pp. 17 ◽  
Author(s):  
FC Barker
Keyword(s):  
Shell Model ◽  
Weak Coupling ◽  
Coupling Model ◽  
Negative Parity ◽  
Positive Parity ◽  
Model Calculations

On the basis of a weak-coupling model, adjustments are made to the interactions used in the full shell model calculations of Millener in order to fit the experimental energies of the low-lying negativeparity levels of 16N and of the low-lying positive-parity levels of 180 and 190 . The predicted energies of the low-lying negative-parity levels of 17N then agree better with experiment, while those for 18N lead to suggested spin assignments for the observed levels.

Carrier tunneling in nanocrystalline silicon–silicon dioxide superlattices: A weak coupling model

2004 ◽  
Vol 69 (23) ◽  
Author(s):  
B. V. Kamenev ◽  
G. F. Grom ◽  
D. J. Lockwood ◽  
J. P. McCafrey ◽  
B. Laikhtman ◽  
...  
Keyword(s):  
Silicon Dioxide ◽  
Weak Coupling ◽  
Coupling Model ◽  
Nanocrystalline Silicon ◽  
Carrier Tunneling ◽  
Silicon Silicon
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