gftool.basis.pole
Representation using poles and the corresponding residues.
Assuming we have only simple poles Green’s functions, we can represent Green’s functions using these poles and their corresponding residues:
where \(ϵ_j\) are the poles and \(r_j\) the corresponding residues. Self-energies can also be represented by the poles after subtracting the static part.
The pole representation is closely related to the Padé approximation, as rational polynomials with numerator degree N bigger then dominator degree M, can also be represented using M poles.
API
Functions
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First derivative of Green's function given by a finite number of poles. |
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Find pole Green's function matching given |
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Find pole Green's function fitting |
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Find pole causal Green's function fitting |
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Retarded time Green's function given by a finite number of poles. |
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Imaginary time Green's function given by a finite number of poles. |
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Green's function given by a finite number of poles. |
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High-frequency moments of the pole Green's function. |
Classes
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Function given by finite number of simple poles and residues. |
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Fermionic Green's function given by finite number of poles and residues. |