User:Tatiana Nebolsina/sandbox

TI-bipolaron (Translation-invariant bipolaron) is elementary quasiparticle in solid state. In distinction from bipolarons with broken symmetry TI-bipolaron is delocalized in space and polarization potential well is lacking (zero polarization charge). TI-bipolaron is a compound boson formed by two electrons with zero spin in singlet state and charge 2e. TI-bipolaron gas being the charged Bose gas is able to experience Bose-Einstein condensation with high transition temperature. In high temperature superconductors TI-bipolaron plays the role of Cooper pair in the limit of strong electron-phonon interaction.