Quantum Green Functions Research Articles

On the description of low energy nuclear resonances with the help of quantum green's functions

It is shown how the appearance of low energy nuclear resonances in the elastic channel can be described with the help of quantumGreen's functions. After the development of the general theory a model is sketched which can be used to perform explicit calculations.

The use of quantum green functions for the calculation of the frequency spectrum of the lattice vibrations of isotopic binary substitutional alloys. I

The paper derives a new method for the calculation of the frequency spectrum of isotopic binary substitutional alloys. The distribution of the admixture in the alloys is described by means of an operator field. Thus an equation for the quantum Green function in the form of functional derivatives can be formulated. In a purely analytical way two methods of successive approximations for the solution of this equation and the expansion in the form of a series in powers of the mass defect are deduced. In the second part of the paper an expansion of the solution in the form of a series of concentrations of the admixture is deduced and a more detailed discussion of the character of the frequency spectrum is performed.

On the theory of the temperature Green's functions

The general theory of quantum Green's functions is developed for thermodynamical systems. The appropriate spectral theorem is proved and the relation of Green's functions to the energy spectrum and thermodynamical properties of the system is established. As an example the energy and damping constant of the “dressed electrons” in a nondegenerate electron gas are calculated.