Variational Ground States of the Holstein Hamiltonian

Leonor Cruzeiro-Hansson, V. M. Kenkre

Ramesh Anishetty, Anton Bovier

Przemysław R. Grzybowski, R. Micnas

Abstract We examine the variational squeezed‐state and the correlated squeezed‐state approach to the ground state of the Holstein–Hubbard model in the case of strong electron–phonon interaction, paying special attention to the electron–hole symmetry of the model Hamiltonian. We have found differences with respect to the results previously reported for the normal and superconducting phases, and present an improved analysis.

Qing-Bao Ren, Qing‐Hu Chen

A novel variational approach is proposed to calculate the ground-state (GS) properties of the two-site Holstein model. By the linear superposition of two coherent states, which simulate the behaviour of the weak and strong coupling limits, we can obtain very accurate GS energy for arbitrary electron–phonon coupling constant. Other GS properties are also discussed. Moreover, the present concise approach is hopefully generalized to many other Holstein models.

Tadahiro Miyao

Ch. Uma Lavanya, Ashok Chatterjee

The Holstein-Hubbard Model in one dimension at half filling with the Gaussian anharmonicity is considered in the present work. In order to solve the Hamiltonian a series of transformations have been applied as a part of the variational calculation approach. The ground state energy of the model is calculated and the existence of metallic phase in the adiabatic regime is observed.