Phonon spectral function of the Holstein polaron

Phonon spectral function of the Holstein polaron

The phonon spectral function of the one-dimensional Holstein model is obtained within weak and strong-coupling approximations based on analytical self-energy calculations. The characteristic excitations found in the limit of small charge-carrier density are related to the known (electronic) spectral properties of Holstein polarons such as the polaron band dispersion. Particular emphasis is laid...

The Holstein Polaron

We describe a variational method to solve the Holstein model for an electron coupled to dynamical, quantum phonons on an infinite lattice. The variational space can be systematically expanded to achieve high accuracy with modest computational resources (12-digit accuracy for the 1d polaron energy at intermediate coupling). We compute ground and low-lying excited state properties of the model at...

Numerical solution of the Holstein polaron problem

Variational study of the Holstein polaron

The paper deals with the ground and the first excited state of the polaron in the one dimensional Holstein model. Various variational methods are used to investigate both the weak coupling and strong coupling cases, as well as the crossover regime between them. Two of the methods, which are presented here for the first time, introduce new elements to the understanding of the nature of the polar...

Optical conductivity of the Holstein polaron.

The momentum average approximation is used to derive a new kind of nonperturbational analytical expression for the optical conductivity (OC) of a Holstein polaron at zero temperature. This provides insight into the shape of the OC, by linking it to the structure of the polaron's phonon cloud. Our method works in any dimension, properly enforces selection rules, can be systematically improved, a...