Electron-Electron Interaction by Exchange of Virtual Phonons: Superconductivity
Figure 4.1 contains the graph of an interaction which we have not so far taken a close look at: an electron emits a virtual phonon, and this phonon is absorbed by another electron. This results in an effective, additional electron-electron interaction. The physical background is simple: the emission of virtual phonons by electrons means a deformation (polarization) of the lattice in the vicinity of the electron. If a second electron is near this polarization cloud, it experiences a force of attraction or repulsion which has nothing to do with the Coulomb interaction between the two electrons. It is with this interaction that we now want to concern ourselves.
KeywordsCooper Pair Persistent Current Critical Magnetic Field Fermi Sphere Particle Number Operator
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