Discussion Overview
The discussion revolves around the formulation of a self-consistent system of Green functions in solid state physics, specifically concerning electrons and phonons within a solid state Hamiltonian framework. Participants explore the implications of their proposed equations and the validity of using Green functions for different quasiparticles.
Discussion Character
- Exploratory
- Technical explanation
- Debate/contested
Main Points Raised
- One participant proposes a self-consistent system of Green functions for electrons and phonons, questioning the validity of this approach.
- Another participant agrees that using the free particle propagator for electrons is acceptable but expresses uncertainty about the phonon case, suggesting that the self-energy operator may need to account for deviations from ideal conditions.
- A different participant raises concerns about whether the proposed system of equations actually exists or if they are independent equations with distinct self-energy contributions for each quasiparticle.
- One participant recommends using the Born-Oppenheimer approximation to simplify the problem, suggesting a two-stage solution process involving fixed nuclei and harmonic approximations for phonons.
- A later reply indicates a desire to avoid the Born-Oppenheimer approximation, implying a preference for a more dynamic approach to the system.
Areas of Agreement / Disagreement
Participants express differing views on the formulation of the Green functions and the applicability of the Born-Oppenheimer approximation. There is no consensus on whether the proposed system of equations is valid or if they should be treated independently.
Contextual Notes
Participants mention the need for clarity in notation when referring to different propagators and the potential complexities introduced by interactions and approximations. The discussion highlights the dependence on specific assumptions regarding quasiparticle behavior.