Anharmonic phonon-electron problem in high temperature superconductors

Owing to the fact that effects of anharmonicities on the electron-phonon pr oblem in high temperature superconductors are relatively unknown, the probl em is solved with the help of double time thermodynamic electron-Green's fu nction theory. The ab initio development of the theory includes a very gene ral and newly formulated Hamiltonian which involves the contributions due t o harmonic-, anharmonic-, localized phonons and electron-phonon and electro ns. This almost approximation-free technique is capable of automatically pr edicting the formation and decay of Cooper pairs in the superconducting cry stals. Expressions for the life times and density of states of electrons ar e obtained in the new framework which are responsible to describe a large n umber of dynamical properties of high temperature superconductors.