THE GROUND STATE OF FRÖHLICH ONE–DIMENSIONAL FERMI–POLARONS

Ya-Dong Song, Huawen Zhang

Jörg Sabczynski, Alexei Sherman, Michael Schreiber

To describe the dynamics of holes in CuO, plancs of high-T,,.supcrconductors we analyse the two-dimensional ¢-J model supplemented with the interaction of holes with nonpolar optical phonons.Elecmentary cxcitations of this modcl arc treated nonadiabatically within the spin-wave approximation on an infinitc squarc latticc by mcans of an itcrative Lanczos algorithm.For paramciter valucs relevant for high-T,.superconductors we have found a sharp crossover in the ground state from a ncarly free cexcitation for small holc-phonon coupling Ю а self-trapped cxcitation for large holc-phonon coupling.In the vicinity of this crossover cocxistence of thesc two types of states and ferron-phonon complexes has been found.We also analysce the dependence of the critical holc-phonon coupling strength on the exchange constant J.

Yucong YIN, Boyang LIU

This study investigates the polaron states formed by an impurity immersed in a spin-1 spinor Bose-Einstein condensate. Employing the Fröhlich Hamiltonian framework, we systematically calculated the ground-state energy and effective mass of polarons in both weak-coupling and strong-coupling regimes. For the weakly interacting regime, the analysis was conducted using second-order perturbation theory. In the strong-coupling regime, we constructed an analytical approximation for the polaron states and performed variational calculations to determine their energy and effective mass. Furthermore, we discussed the transition from the mobile state to the self-trapped state of the polaron in the strong-coupling region. We also estimate the signatures of polaron effects in spinor BEC for the future experiments.

Marcel Griesemer, Ulrich Linden

Xuezao Ren, Xu Liao, Lei Li +1 more

Vladimir Onoochin

The functional of the ground-state energy of large polarons is considered. After a canonical transformation and elimination of the field oscillators variables, the functional is presented in form convenient for further analysis. One can conclude that the type of ground state of each field oscillator is the coherent state.