Arbitrary decay of solutions for a singular nonlocal viscoelastic problem with a possible damping term

2013 ◽  
Vol 93 (6) ◽  
pp. 1150-1163
Author(s):  
Gang Li ◽  
Yun Sun ◽  
Wenjun Liu
Author(s):  
Olle Eriksson ◽  
Anders Bergman ◽  
Lars Bergqvist ◽  
Johan Hellsvik

In the previous chapters we described the basic principles of density functional theory, gave examples of how accurate it is to describe static magnetic properties in general, and derived from this basis the master equation for atomistic spin-dynamics; the SLL (or SLLG) equation. However, one term was not described in these chapters, namely the damping parameter. This parameter is a crucial one in the SLL (or SLLG) equation, since it allows for energy and angular momentum to dissipate from the simulation cell. The damping parameter can be evaluated from density functional theory, and the Kohn-Sham equation, and it is possible to determine its value experimentally. This chapter covers in detail the theoretical aspects of how to calculate theoretically the damping parameter. Chapter 8 is focused, among other things, on the experimental detection of the damping, using ferromagnetic resonance.


Author(s):  
Michael Kachelriess

After a brief review of the operator approach to quantum mechanics, Feynmans path integral, which expresses a transition amplitude as a sum over all paths, is derived. Adding a linear coupling to an external source J and a damping term to the Lagrangian, the ground-state persistence amplitude is obtained. This quantity serves as the generating functional Z[J] for n-point Green functions which are the main target when studying quantum field theory. Then the harmonic oscillator as an example for a one-dimensional quantum field theory is discussed and the reason why a relativistic quantum theory should be based on quantum fields is explained.


2021 ◽  
Vol 500 (1) ◽  
pp. 125136
Author(s):  
Adel M. Al-Mahdi ◽  
Mohammad M. Al-Gharabli ◽  
Salim A. Messaoudi

2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
Osama Moaaz ◽  
George E. Chatzarakis ◽  
Thabet Abdeljawad ◽  
Clemente Cesarano ◽  
Amany Nabih

Abstract The aim of this work is to improve the oscillation results for second-order neutral differential equations with damping term. We consider the noncanonical case which always leads to two independent conditions for oscillation. We are working to improve related results by simplifying the conditions, based on taking a different approach that leads to one condition. Moreover, we obtain different forms of conditions to expand the application area. An example is also given to demonstrate the applicability and strength of the obtained conditions over known ones.


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