Pekar's ansatz and the strong coupling problem in polaron theory
V.D. Lakhno Institute of Mathematical Problems of Biology, Keldysh Institute of Applied Mathematics, Russian Academy of Sciences, Prof. Vitkevich str. 1, Pushchino, Moscow Region, 142290, Russian Federation
The translationally invariant polaron theory of Tulub is discussed in detail which makes no use the Pekar's ansatz (believed to provide the asymptotically exact solution in the strong coupling limit) and fundamentally produces a lower-energy polaron than when using the anzatz. In the case of the bipolaron, the theory yields the best values for bonding energy and for critical stability parameters. A variety of physical implications of the existence of translationally invariant polarons and bipolarons are discussed.
Keywords: Froehlich Hamiltonian, Lee—Low—Pines transformation, weak coupling, Bose condensate, F-center PACS:71.38.−k, 74.20.−z, 74.72.−h (all) DOI:10.3367/UFNe.0185.201503d.0317 URL: https://ufn.ru/en/articles/2015/3/d/ Citation: Lakhno V D "Pekar's ansatz and the strong coupling problem in polaron theory" Phys. Usp.58 295–308 (2015)