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...

The behavior of the 1D Holstein polaron is described, with emphasis on lattice coarsening effects, by distinguishing between adiabatic and nonadiabatic contributions to the local correlations and dispersion properties. The original and unifying systematization of the crossovers between the different polaron behaviors, usually considered in the literature, is obtained in terms of quantum to clas...

We report an electron paramagnetic resonance investigation of the grain size effects on the polaron transport in the paramagnetic regime of nanosized La2/3Ca1/3MnO3 manganites. The temperature dependences of the EPR integral intensity were analyzed in terms of spin–spin exchange interaction and small polaron hopping scenarios. The polaron activation energy decreases with the reduction of the gr...

We compare the role of the three-site terms added to the t-J models in the SU(2) and the Ising cases in the extremely low doping regime, i.e. when a single hole added to the strongly interacting half-filled system becomes a polaron. We show that in the realistic Ising case the threesite terms play a vital role in the polaron movement and should never be neglected unlike in the SU(2) case.

In the study of open quantum systems, the polaron transformation has recently attracted a renewed interest as it offers the possibility to explore the strong system-bath coupling regime. Despite this interest, a clear and unambiguous analysis of the regimes of validity of the polaron transformation is still lacking. Here we provide such a benchmark, comparing second order perturbation theory re...

We report on the evolution of the polaron and phonon mode properties in amorphous tungsten oxide thin films measured by spectroscopic ellipsometry in the infrared to ultraviolet spectral regions as a function of the intercalated proton density. A parametric physical model dielectric function is presented, which excellently describes the ellipsometry data over a large intercalated charge-density...

the one photon absorption (opa) cross section of a current carrying two-orbital quantum dot (qd) with strong electron-phonon interaction (polaron regime) is considered. using the self-consistent non-equilibrium hartree-fock (hf) approximation, we determine the dependence of opa cross section on the applied bias voltage, the strength of effective electron-electron interaction, and level spacing ...

Keeping the full quantum nature of the problem, we compute the relaxation time of the Holstein polaron in one dimension after it was driven far from the equilibrium by a strong oscillatory pulse. Just after the pulse, the polaron's kinetic energy increases and subsequently exhibits a relaxation-type decrease with simultaneous emission of phonons. In the weak coupling regime, partial tunneling o...