Based on an exact expression for the self-energy of the Jahn-Teller polaron, we find that symmetry of pseudospin rotation makes the vertex correction much less effective than that for the Holstein polaron. This ineffectiveness brings about a smaller effective mass ${m}^{*}$ and a quantitatively different large-to-small polaron crossover, as examined by exact diagonalization in a two-site system. In the strong-coupling and antiadiabatic region, a rigorous analytic expression is found for ${m}^{*}.$ Based on an exact expression for the self-energy of the Jahn-Teller polaron, we find that symmetry of pseudospin rotation makes the vertex correction much less effective than that for the Holstein polaron. This ineffectiveness brings about a smaller effective mass ${m}^{*}$ and a quantitatively different large-to-small polaron crossover, as examined by exact diagonalization in a two-site system. In the strong-coupling and antiadiabatic region, a rigorous analytic expression is found for ${m}^{*}.$

arXiv:cond-mat/9911404Physical review. B, Condensed matterApr 1, 200016 citations

Band Structure of the Jahn-Teller Polaron from Quantum Monte Carlo

P. E. Kornilovitch

A path-integral representation for the Jahn-Teller polaron (JTP) is constructed. It leads to a perturbation series that can be summed exactly by the diagrammatic quantum Monte Carlo technique. The ground-state energy, effective mass, spectrum, and density of states of the three-dimensional JTP are calculated with no systematic errors. The band structure of JTP is found to be similar to that of the Holstein polaron. The mass of JTP increases exponentially with the coupling constant. At small phonon frequencies, the spectrum of JTP is flat at large momenta, which leads to a strongly distorted density of states with a massive peak at the top of the band.A path-integral representation for the Jahn-Teller polaron (JTP) is constructed. It leads to a perturbation series that can be summed exactly by the diagrammatic quantum Monte Carlo technique. The ground-state energy, effective mass, spectrum, and density of states of the three-dimensional JTP are calculated with no systematic errors. The band structure of JTP is found to be similar to that of the Holstein polaron. The mass of JTP increases exponentially with the coupling constant. At small phonon frequencies, the spectrum of JTP is flat at large momenta, which leads to a strongly distorted density of states with a massive peak at the top of the band.

arXiv:cond-mat/9910436Physical Review LettersFeb 14, 200020 citations

Aspects of Polaron Theory

Nikolay N. Bogolubov, Nikolay N. Bogolubov

WORLD SCIENTIFIC eBooksSep 1, 200831 citations

Some approaches to polaron theory

Nikolay N. Bogolubov, Nikolay N. Bogolubov

Foundations of PhysicsNov 1, 19852 citations

Numerical study of the E⊗e Jahn-Teller polaron and bipolaron

Samir El Shawish, J. Bonča, Li-Chung Ku +1 more

The properties of the polaron and bipolaron are explored in the one-dimensional Jahn-Teller model with dynamical quantum phonons. The ground-state properties of the polaron and bipolaron are computed using a recently developed variational method. Dynamical properties of the ground state of a polaron are investigated by calculating the optical conductivity $\ensuremath{\sigma}(\ensuremath{\omega}).$ Our numerical results suggest that the Jahn-Teller and Holstein polarons are similar. However, in the strong-coupling regime qualitative differences in $\ensuremath{\sigma}(\ensuremath{\omega})$ between the two models are found and discussed. The influence of the electron-phonon coupling and the electrostatic repulsion on the bipolaron binding energy, bipolaron masses, and correlation functions is investigated.The properties of the polaron and bipolaron are explored in the one-dimensional Jahn-Teller model with dynamical quantum phonons. The ground-state properties of the polaron and bipolaron are computed using a recently developed variational method. Dynamical properties of the ground state of a polaron are investigated by calculating the optical conductivity $\ensuremath{\sigma}(\ensuremath{\omega}).$ Our numerical results suggest that the Jahn-Teller and Holstein polarons are similar. However, in the strong-coupling regime qualitative differences in $\ensuremath{\sigma}(\ensuremath{\omega})$ between the two models are found and discussed. The influence of the electron-phonon coupling and the electrostatic repulsion on the bipolaron binding energy, bipolaron masses, and correlation functions is investigated.

arXiv:cond-mat/0211099Physical review. B, Condensed matterJan 10, 200329 citations

{m}^{*}

and a quantitatively different large-to-small polaron crossover, as examined by exact diagonalization in a two-site system. In the strong-coupling and antiadiabatic region, a rigorous analytic expression is found for

{m}^{*}.