Berlin 2015 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 112: Correlated Electrons: (General) Theory 3

TT 112.3: Talk

Friday, March 20, 2015, 10:00–10:15, H 3010

Phonon spectral function from continuous-time quantum Monte Carlo — •Manuel Weber, Fakher F. Assaad, and Martin Hohenadler — Institut für Theoretische Physik und Astrophysik, Universität Würzburg, 97074 Würzburg, Germany

We show that the phonon spectral function of electron-phonon systems can be measured with the CT-INT quantum Monte Carlo method with the help of a generating functional. We study the evolution of the phonon spectral function across metal-insulator transitions driven by electron-phonon and electron-electron interaction in the half-filled spinless Holstein and spinful Holstein-Hubbard models, respectively. In the adiabatic regime, the phonons soften at the zone boundary on approaching the Peierls transition. In the metallic phase, we observe the hybridization of the phonon mode with the particle-hole continuum, and a pronounced transfer of spectral weight between phonon and particle-hole excitations as a function of the phonon frequency.