Computing Green's function of elasticity in a half-plane with impedance boundary condition

2006 ◽  
Vol 334 (12) ◽  
pp. 725-731 ◽  
Author(s):  
Mario Durán ◽  
Eduardo Godoy ◽  
Jean-Claude Nédélec
1966 ◽  
Vol 44 (11) ◽  
pp. 2915-2925 ◽  
Author(s):  
R. W. Breithaupt

The problem solved previously by Jull (1964) for a perfectly conducting half-plane is extended to the case of an impedance half-plane. As assumed by Jull, the direction of the incident wave is normal to both the magnetostatic field and the diffracting edge. The plasma is characterized by a permittivity tensor; and only the TM incident field is considered, as the anisotropy does not affect an incident TE wave. The impedance boundary condition is found to introduce unidirectional surface waves propagating at some angle into or away from the surface, as well as the usual radiated far fields.


2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Haiming Yuan ◽  
Xian-Hui Ge

Abstract The “pole-skipping” phenomenon reflects that the retarded Green’s function is not unique at a pole-skipping point in momentum space (ω, k). We explore the universality of pole-skipping in different geometries. In holography, near horizon analysis of the bulk equation of motion is a more straightforward way to derive a pole-skipping point. We use this method in Lifshitz, AdS2 and Rindler geometries. We also study the complex hydrodynamic analyses and find that the dispersion relations in terms of dimensionless variables $$ \frac{\omega }{2\pi T} $$ ω 2 πT and $$ \frac{\left|k\right|}{2\pi T} $$ k 2 πT pass through pole-skipping points $$ \left(\frac{\omega_n}{2\pi T},\frac{\left|{k}_n\right|}{2\pi T}\right) $$ ω n 2 πT k n 2 πT at small ω and k in the Lifshitz background. We verify that the position of the pole-skipping points does not depend on the standard quantization or alternative quantization of the boundary theory in AdS2× ℝd−1 geometry. In the Rindler geometry, we cannot find the corresponding Green’s function to calculate pole-skipping points because it is difficult to impose the boundary condition. However, we can still obtain “special points” near the horizon where bulk equations of motion have two incoming solutions. These “special points” correspond to the nonuniqueness of the Green’s function in physical meaning from the perspective of holography.


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