# Questions tagged [greens-functions]

Questions related to Green's functions and their role in matter modeling.

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### Generation of the eletromagnetic wave or electric current by the photo-excitation

Suppose there is an incident photo with a specific frequency hitting the material; the incident photo is absorbed by this material. Meanwhile, the material is excited by this incident photo and ...
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### The Dynamic Constant Matrix for the Green Function in the Thermal Conductance Calculation

When computing the thermal transmission coefficient, the green function needs to be computed first; for example, $G^{R}_{scattering\:region}=\left[\left(\omega+i0^{+}\right)^{2}I-D\right]^{-1}$, where ...
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### Difference of the Transmission Coefficient between Thermal and Charge Conductance by Nonequilibirum Green Function Method

The equation 57 in the reference [Jian-Sheng Wang, Jian Wang and J. T. Lu, Quantum thermal transport in nanostructures, Eur. Phys. J. B 62, 381 (2008)] explains the the transmission coefficient for ...
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### Tools for symbolic calculations of quantum transport using the Keldysh NEGF formalism [closed]

I am looking for tools for symbolic calculation of quantum transport or quantum mechanics that involves Keldysh NEGF (non-equilibrium Green's function) formalism. The closest tool I heard/seen is <...
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### About the surface Greens function method for calculating the surface state

Currently I'm using some software package to do the data analysis from the DFT calculation so that I can study the surface state of some topological insulator. I found that the method they use is ...
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### Given that Kohn-Sham DFT is strictly a ground-state method (at 0 K), how is it sufficient to describe materials in real-life applications?

Kohn-Sham DFT appears to be so popular even though it is strictly a ground-state method - all calculations are done at 0 K. How then, is it so popular when describing materials that have real-life ...
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### Approximation of Dyson's Equation

I've been trying to learn about Green's function in the context of computational chemistry by reading Szabo and Ostlund's Modern Quantum Chemistry. I've reached a section about the one particle many ...
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