A new numerical algorithm for the analytic continuation of Green`s functions
- Exxon Research and Engineering Company, Annandale, NJ (United States)
- Univ. of Colorado, Boulder, CO (United States)
The need to calculate the spectral properties of a Hermitian operation H frequently arises in the technical sciences. A common approach to its solution involves the construction of the Green`s function operator G(z) = [z - H]{sup -1} in the complex z plane. For example, the energy spectrum and other physical properties of condensed matter systems can often be elegantly and naturally expressed in terms of the Kohn-Sham Green`s functions. However, the nonanalyticity of resolvents on the real axis makes them difficult to compute and manipulate. The Herglotz property of a Green`s function allows one to calculate it along an arc with a small but finite imaginary part, i.e., G(x + iy), and then to continue it to the real axis to determine quantities of physical interest. In the past, finite-difference techniques have been used for this continuation. We present here a fundamentally new algorithm based on the fast Fourier transform which is both simpler and more effective. 14 refs., 9 figs.
- OSTI ID:
- 440759
- Journal Information:
- Journal of Computational Physics, Vol. 126, Issue 1; Other Information: PBD: Jun 1996
- Country of Publication:
- United States
- Language:
- English
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