Quasiparticle momentum distributions in the t-J model

理 西本, 幸則 太田, R. Eder

Fabian Biebl

We consider the thermalization of the momentum distribution in two one-dimensional models. The first one is the integrable Hubbard model with an additional integrability breaking term in the Hamiltonian, which is a next-to-nearest-neighbor hopping term. This has been previously investigated by Fürst et al. (PRE 86:031122, 2012; PRE 88:012108, 2013). They considered several initial quasiparticle momentum distributions and their relaxation times for different strengths of the next-to-nearest-neighbor hopping amplitude. We find the dependence of the thermalization rates on the model parameters, on the filling and on temperature for any initial quasiparticle momentum distribution in the regime of small integrability breaking using a Boltzmann equation. The second model is an effective model describing a chain of manganite octahedra. There, we investigate a the temperature dependence of the relaxation rates for reasonable choices of the model parameters and the filling.

Hong Q. Ding

MIKHAIL V. ZVEREV, M. Baldo

The structure of the ground state beyond the instability point of the quasiparticle system with a Fermi-step momentum distribution is studied within the model of a Fermi liquid with a strong repulsive interaction. A ground-state rearrangement occurs as the interaction strength is increased beyond a certain critical value. Numerical investigation of the initial stage of this structural transition shows that there are two temperature regions, corresponding to different scenarios of the rearrangement. While for temperature T larger than some characteristic temperature the behaviour of the system is the same as that in the case of fermion condensation, for an intermediate structure with a multi-connected quasiparticle momentum distribution arises.

F. Lema, Armando A. Aligia

A. Ramšak, Igor Sega, Peter Prelovšek