Spectral signatures of many-body localization of interacting photons (P. Roushan - Google Inc., USA)

28.06.2018 15:15 – 16:15

Statistical mechanics is founded on the assumption that a system can reach thermal equilibrium, regardless of the starting state. Interactions between particles facilitate thermalization, but, can interacting systems always equilibrate regardless of parameter values ? The energy spectrum of a system can answer this question and reveal the nature of the underlying phases. However, most experimental techniques only indirectly probe the many-body energy spectrum. Using a chain of nine superconducting qubits, we implement a novel technique for directly resolving the energy levels of interacting photons. We benchmark this method by capturing the intricate energy spectrum predicted for 2D electrons in a magnetic field, the Hofstadter buttery. Increasing disorder leads to the formation of a mobility edge, where the spatial extent of energy eigenstates shrink at the edge of the energy band. At strong disorder, the energy levels cease to repel one another and their statistics approaches a Poisson distribution - the hallmark of transition from metallic to the many-body localized phase. Our work introduces a new many-body spectroscopy technique to study quantum phases of matter.
If time permit, I will also discuss our progress toward demonstrating quantum supremacy based on Floquet dynamics.

Lieu

Bâtiment: Ecole de Physique

Auditoire Stückelberg

entrée libre