Projection-Reduction Approach to Optical Conductivities for an Electron-Phonon System and Their Diagram Representation

Figure 2

Schematic diagrams of (a) |𝐶_𝛽𝜆(𝑞)|²𝐺⁽⁻⁾_𝜆𝛼(𝜔)𝑃₊(𝜆,𝛼), (b) |𝐶_𝛽𝜆(𝑞)|²𝐺⁽⁺⁾_𝜆𝛼(𝜔)𝑃₋(𝜆,𝛼), (c) |𝐶_𝜆𝛼(𝑞)|²𝐺⁽⁻⁾_𝛽𝜆(𝜔)𝑃₊(𝛽,𝜆), and (d) |𝐶_𝜆𝛼(𝑞)|²𝐺⁽⁺⁾_𝛽𝜆(𝜔)𝑃₋(𝛽,𝜆) in Γ⁽⁰⁾_𝛽𝛼(𝜔).

(a)

(b)

(c)

(d)