DQMP Seminar - Many-body delocalization and energy transport in a system with power-law interaction

13.03.2018 13:00 – 14:30

I will discuss the delocalization and heat transport in a strongly disordered many-body system due to a power-law interaction. One experimentally relevant realization of this problem is the effect of Coulomb interaction in Anderson insulators. In particular, experiments demonstrating efficient heat transport through the bulk of quantum Hall systems served as a motivation for this work. Particle-hole excitations built on localized electron states are viewed as two-level systems (“spins”) randomly distributed in space and energy and coupled due to electron-electron interaction. We identify the character of energy transport and evaluate the spin relaxation rate and the thermal conductivity. For physically relevant cases of two-dimensional and three-dimensional “spin" systems with 1/r^{3} dipole-dipole interaction (originating from the conventional 1/r Coulomb interaction between electrons), the found thermal conductivity κ scales with temperature as κ ∝ T^{3} and κ ∝ T^{4/3}, respectively. Our results are of relevance also to other realizations of random spin Hamiltonians with long-range interactions.

We also study the many-body delocalization transition in a finite-size system with power-law interaction. In this context, I will demonstrate a connection of this problem with Anderson localization on random regular graphs. I will present analytical results for the scaling of the transition as well as numerical results based on statistics of many-body energy levels and eigenfunctions.

Lieu

Bâtiment: Ecole de Physique

Auditoire Stückelberg

Organisé par

Département de physique de la matière quantique

Intervenants

Alexander Mirlin, Prof. Dr. - Karlsruher Institut für Technologie

entrée libre

Classement

Catégorie: Séminaire