scholarly journals Time-retarded damping and magnetic inertia in the Landau-Lifshitz-Gilbert equation self-consistently coupled to electronic time-dependent nonequilibrium Green functions

2019 ◽  
Vol 99 (13) ◽  
Author(s):  
Utkarsh Bajpai ◽  
Branislav K. Nikolić
Keyword(s):  
Time Dependent ◽  
Green Functions ◽  
Nonequilibrium Green Functions

scholarly journals Integrals of the motion and green functions for time-dependent mass harmonic oscillators

2018 ◽  
Vol 64 (1) ◽  
pp. 30
Author(s):  
Surarit Pepore
Keyword(s):  
Harmonic Oscillator ◽  
Harmonic Oscillators ◽  
Time Dependent ◽  
Green Functions ◽  
Feynman Path Integral ◽  
Feynman Path ◽  
Damped Harmonic Oscillator ◽  
System Trajectory ◽  
Dependent Mass ◽  
Motion Method

The application of the integrals of the motion of a quantum system in deriving Green function or propagator is established. The Greenfunction is shown to be the eigenfunction of the integrals of the motion which described initial points of the system trajectory in the phasespace. The explicit expressions for the Green functions of the damped harmonic oscillator, the harmonic oscillator with strongly pulsatingmass, and the harmonic oscillator with mass growing with time are obtained in co-ordinate representations. The connection between theintegrals of the motion method and other method such as Feynman path integral and Schwinger method are also discussed.

scholarly journals Quantum Energy Expectation in Periodic Time-Dependent Hamiltonians via Green Functions

2009 ◽  
Vol 2009 ◽  
pp. 1-30
Author(s):  
César R. de Oliveira ◽  
Mariza S. Simsen
Keyword(s):  
Time Dependent ◽  
Green Functions ◽  
Quantum Energy ◽  
Expectation Value ◽  
Energy Expectation ◽  
Floquet Operator ◽  
Time Average ◽  
Time Periodic

LetUFbe the Floquet operator of a time periodic HamiltonianH(t). For each positive and discrete observableA(which we call aprobe energy), we derive a formula for the Laplace time average of its expectation value up to timeTin terms of its eigenvalues and Green functions at the circle of radiuse1/T. Some simple applications are provided which support its usefulness.

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