Related papers: Light Bipolarons Stabilized by Peierls Electron-Ph…
The search for room-temperature superconducting materials has been at the center of modern research for decades. The recent discovery of high-temperature superconductivity, under extreme pressure in hydrogen-rich materials, is a tremendous…
We investigate full quantum mechanical evolution of two electrons nonlinearly coupled to quantum phonons and simulate the dynamical response of the system subject to a short spatially uniform optical pulse that couples to dipole-active…
An understanding of high temperature superconductivity clearly requires the nature of its normal state, however the normal state of the cuprates is poorly understood. One possible explanation is the bipolaronic model where mobile, heavily…
The properties of the electron-phonon interaction in the presence of a sizable electronic repulsion at finite doping are studied by investigating the metallic phase of the Hubbard-Holstein model with Dynamical Mean Field Theory. Analyzing…
The Yang-Mills description of phonons and the consequent structure of electron liquids in strongly anharmonic crystals such as metal oxides is shown to yield an attractive electron-phonon interaction, and thus an instability towards the…
Bipolaronic superconductivity is an exotic pairing mechanism proposed for materials like Ba$_{1-x}$K$_x$BiO$_3$ (BKBO); however, conclusive experimental evidence for a (bi)polaron metallic state in this material remains elusive. Here, we…
We revisit the two-site Hubbard-Holstein model by using extended phonon coherent states. The nontrivial singlet bipolaron is studied exactly in the whole coupling regime. The ground-state (GS) energy and the double occupancy probability are…
It is shown that the bipolaron ground state is described by a delocalized wave function. For a two-parameter wave function, the lowest variation estimate of the ground state energy in the strong coupling limit is found to be $E=- 0,414125…
Results of a phenomenological Monte carlo calculation for a 2D electron-phonon Holstein model near a Peierls-CDW transition are presented. Here the zero Matsubara frequency part of the phonon action is dominant and we approximated it by a…
We study a multiorbital Hubbard model coupled to local Jahn-Teller phonons to investigate the superconducting state realized in fullerides. A weak-coupling approach is employed in combination with a local self-energy approximation. In…
We present a simple model for the electron-phonon interactions between the energy subbands in polyacene field-effect transistors and the vibrations of the crystal. We introduce a generalized Su-Schrieffer-Heeger model, arguing that the…
Mobile impurities in a Bose-Einstein condensate form quasiparticles called polarons. Here, we show that two such polarons can bind to form a bound bipolaron state. Its emergence is caused by an induced nonlocal interaction mediated by…
This paper is concerned with Fr\"ohlich polarons subject to external electromagnetic fields in the limit of large electron-phonon coupling. To leading order in the coupling constant, $\sqrt\alpha$, the ground state energy is shown to be…
We investigate the role of specific phonon mode symmetries for the room temperature superconductivity in atomic hydrogen under large pressure. Using anisotropic Migdal-Eliashberg theory with ab initio input from density functional theory,…
Topological phononic insulators are the counterpart of three-dimensional quantum spin Hall insulators in phononic systems and, as such, their topological surfaces are characterized by Dirac cone-shaped gapless edge states arising as a…
We predict a strong enhancement of the critical temperature in a conventional Bardeen-Cooper-Schrieffer (BCS) superconductor in the presence of a bosonic condensate of exciton-polaritons. The effect depends strongly on the ratio of the…
We study the problem of the phonon-induced electron-electron interaction in a solid. Starting with a Hamiltonian that contains an electron-phonon interaction, we perform a similarity renormalization transformation to calculate an effective…
Here we consider an interacting electron-phonon system within the framework of extended Holstein-Hubbard model at strong enough electron-phonon interaction limit in which (bi)polarons are the essential quasiparticles of the system. It is…
With the superconducting cuprates in mind, a set of unitary transformations was used to decouple electrons and phonons in the strong-coupling limit. While phonons remain almost unrenormalised, electrons are transformed into itinerent…
We investigate the interplay of phonons and correlations in superconducting pairing by introducing a model Hamiltonian with on-site repulsion and couplings to several vibration branches having the Cu-O plane of the cuprates as a paradigm.…