LAYER POLARIZATIONS AND DIELECTRIC SUSCEPTIBILITIES OF ANTIFERROELECTRIC THIN FILMS

2003 ◽  
Vol 17 (25) ◽  
pp. 1343-1347 ◽  
Author(s):  
J. M. WESSELINOWA ◽  
S. TRIMPER
Keyword(s):  
Thin Films ◽  
Surface Layer ◽  
Ising Model ◽  
Green’S Function ◽  
Green's Function ◽  
Low Temperatures ◽  
Transverse Field ◽  
Thermal Fluctuations ◽  
Ferroelectric Thin Films ◽  
Function Technique

The polarization and susceptibility of thin antiferroelectric films are presented using a Green's function technique within an Ising model in a transverse field. Both quantities vary with the numbers of layers. Whereas at low temperatures the suceptibilty of the surface layer increases stronger than that of the second layer, the polarization of the surface is smaller compared to the polarization of the second layer. Such behavior has no counterpart in ferroelectric thin films. The effect is attributed to inhomogeneous thermal fluctuations.

A reformulation of the dimer problem

1968 ◽  
Vol 46 (15) ◽  
pp. 1681-1684 ◽  
Author(s):  
R. W. Gibberd
Keyword(s):  
Ising Model ◽  
Partition Function ◽  
Green’S Function ◽  
Green's Function ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Function Technique ◽  
Value Of Time ◽  
Expectation Value

It is shown that the partition function of the generalized dimer problem can be formulated in terms of a vacuum-to-vacuum expectation value of time-ordered operators. This expression is then evaluated by using Green's function technique, which has already been used in conjunction with the Ising model and ferroelectric problem.

CRITICAL BEHAVIOUR OF THE TRANSVERSE ISING MODEL WITH MODIFIED SURFACE EXCHANGE

2001 ◽  
Vol 15 (04) ◽  
pp. 379-384 ◽  
Author(s):  
J. M. WESSELINOWA ◽  
S. TRIMPER
Keyword(s):  
Monte Carlo ◽  
Surface Layer ◽  
Ising Model ◽  
Exchange Coupling ◽  
Three Dimensional ◽  
Transverse Field ◽  
Function Technique ◽  
Surface Phenomena ◽  
Surface Exchange ◽  
Modified Surface

Using a Green's function technique combined with the transfer-matrix method for the analysis of surface phenomena, we have studied a three-dimensional Ising model in a transverse field with a modified surface exchange coupling. The surface layer-polarization exponent is obtained as β s = 0.775 ± 0.006 which is entirely different from the bulk exponent of β = 0.317 ± 0.006. The results are in agreement with those based on renormalization group arguments and on Monte-Carlo simulations.

Green's function approach to the Ising model

1969 ◽  
Vol 47 (7) ◽  
pp. 769-777 ◽  
Author(s):  
K. C. Lee ◽  
Robert Barrie
Keyword(s):  
Ising Model ◽  
Green’S Function ◽  
Green's Function ◽  
Body Problem ◽  
Equations Of Motion ◽  
Function Technique ◽  
Many Body ◽  
One Dimensional ◽  
Spinless Fermion ◽  
The One

It is shown that the spin [Formula: see text] Ising model can be formulated as a spinless fermion many-body problem and that the Green's function technique can be applied to it. The hierarchy of Green's function equations of motion terminates at the (q + 1)-particle Green's function, where q is the coordination number. This finite number of equations yields Fisher's transformation of correlations. The technique discussed in this paper can be used to obtain exact results for the one-dimensional Ising model.

THE EMPIRICAL GREEN’S FUNCTION TECHNIQUE MODIFICATION FOR ACCELEROGRAM SYNTHESIS IN LOWSEISMICITY REGIONS

2018 ◽  
Vol 12 (5-6) ◽  
pp. 72-80
Author(s):  
A. A. Krylov
Keyword(s):  
Green’S Function ◽  
Green's Function ◽  
Main Shock ◽  
Amplitude Spectrum ◽  
Strong Motion ◽  
Function Technique ◽  
Focal Region ◽  
Empirical Green’S Function ◽  
Epicentral Zone ◽  
Empirical Green's Function

In the absence of strong motion records at the future construction sites, different theoretical and semi-empirical approaches are used to estimate the initial seismic vibrations of the soil. If there are records of weak earthquakes on the site and the parameters of the fault that generates the calculated earthquake are known, then the empirical Green’s function can be used. Initially, the empirical Green’s function method in the formulation of Irikura was applied for main shock record modelling using its aftershocks under the following conditions: the magnitude of the weak event is only 1–2 units smaller than the magnitude of the main shock; the focus of the weak event is localized in the focal region of a strong event, hearth, and it should be the same for both events. However, short-termed local instrumental seismological investigation, especially on seafloor, results usually with weak microearthquakes recordings. The magnitude of the observed micro-earthquakes is much lower than of the modeling event (more than 2). To test whether the method of the empirical Green’s function can be applied under these conditions, the accelerograms of the main shock of the earthquake in L'Aquila (6.04.09) with a magnitude Mw = 6.3 were modelled. The microearthquake with ML = 3,3 (21.05.2011) and unknown origin mechanism located in mainshock’s epicentral zone was used as the empirical Green’s function. It was concluded that the empirical Green’s function is to be preprocessed. The complex Fourier spectrum smoothing by moving average was suggested. After the smoothing the inverses Fourier transform results with new Green’s function. Thus, not only the amplitude spectrum is smoothed out, but also the phase spectrum. After such preliminary processing, the spectra of the calculated accelerograms and recorded correspond to each other much better. The modelling demonstrate good results within frequency range 0,1–10 Hz, considered usually for engineering seismological studies.

An application of Green’s function technique for computing well inflow without radial flow assumption

2017 ◽  
Vol 21 (5-6) ◽  
pp. 1049-1058
Author(s):  
A. V. Novikov ◽  
V. S. Posvyanskii ◽  
D. V. Posvyanskii
Keyword(s):  
Green’S Function ◽  
Green's Function ◽  
Radial Flow ◽  
Function Technique
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