Born expansion of Green’s function

Target entity: Born expansion of Green’s function
Context triple: [Born approximation, relatedTo, Born expansion of Green’s function]

• A. Born–Huang expansion
  The Born–Huang expansion is a quantum mechanical method that systematically improves upon the Born–Oppenheimer approximation by including couplings between electronic and nuclear motions in molecular systems.
• B. Rayleigh–Schrödinger perturbation theory
  Rayleigh–Schrödinger perturbation theory is a fundamental method in quantum mechanics for approximating the energies and states of a system by treating interactions as small corrections to an exactly solvable problem.
• C. Herzberg–Teller approximation
  The Herzberg–Teller approximation is a refinement in molecular spectroscopy that accounts for vibronic coupling by allowing electronic transition dipole moments to depend on nuclear coordinates, explaining intensity in otherwise forbidden transitions.
• D. Sommerfeld expansion in statistical mechanics
  The Sommerfeld expansion in statistical mechanics is an asymptotic method used to approximate integrals involving Fermi–Dirac distributions at low temperatures, widely applied to calculate thermodynamic properties of degenerate electron gases in metals.
• E. Eliashberg theory
  Eliashberg theory is an extension of BCS superconductivity that incorporates strong-coupling and frequency-dependent effects to more accurately describe real superconducting materials.
• F. None of above. chosen
• G. Unsure - the case is ambiguous/there is not enough information to decide.

Target entity: Born expansion of Green’s function
Target entity description: The Born expansion of Green’s function is a perturbative series representation used in scattering theory to express the Green’s function as a sum of successive interaction terms.

• A. Born–Huang expansion
  The Born–Huang expansion is a quantum mechanical method that systematically improves upon the Born–Oppenheimer approximation by including couplings between electronic and nuclear motions in molecular systems.
• B. Rayleigh–Schrödinger perturbation theory
  Rayleigh–Schrödinger perturbation theory is a fundamental method in quantum mechanics for approximating the energies and states of a system by treating interactions as small corrections to an exactly solvable problem.
• C. Herzberg–Teller approximation
  The Herzberg–Teller approximation is a refinement in molecular spectroscopy that accounts for vibronic coupling by allowing electronic transition dipole moments to depend on nuclear coordinates, explaining intensity in otherwise forbidden transitions.
• D. Sommerfeld expansion in statistical mechanics
  The Sommerfeld expansion in statistical mechanics is an asymptotic method used to approximate integrals involving Fermi–Dirac distributions at low temperatures, widely applied to calculate thermodynamic properties of degenerate electron gases in metals.
• E. Eliashberg theory
  Eliashberg theory is an extension of BCS superconductivity that incorporates strong-coupling and frequency-dependent effects to more accurately describe real superconducting materials.
• F. None of above. chosen