Workshop 2025: Topological delocalization in two-dimensional quantum walks
Session Information
Location: Lecture room F3213 - 01
Day: Wednesday, 14 May
Time: 18:00 - 19:00
Chairperson: -
Presentation Details
Presentation Type: Poster presentation
Title: Topological delocalization in two-dimensional quantum walks
Abstract: Quantum walks, the quantum mechanical generalization of random walks, are interesting for quantum information processing, but also as simple dynamical systems that have topological features. One such feature is a delocalization of quantum walks under maximal disorder, which we study here. Disorder that does not fluctuate in time, generically induces in 1 and 2 dimensional coherent dynamical systems (such as quantum walks) Anderson localization. Thus, an initially localized wavepacket does not spread off to infinity, but its extent remains bounded by the localization length. Increasing the amount of disorder makes the localization stronger, localization length shorter. However, for quantum walks we find [1] that increasing the amount of disorder to the maximum value leads to first an increase of the localization length, and then a change in the dynamics from localized to diffusive. The reason is that maximal disorder tunes the quantum walk to a critical point between phases with different topological invariants.
[1]: JK Asboth, A Mallick, Phys. Rev. B 102, 224202 (2020)
Presenter
Dr Janos Asboth
BME TTK | Hungary
Authors
1. JK Asbóth | BME TTK and HUN-REN Wigner FK
2. A. Mallick | Uniwersytet Jagiellonski, Lojasiewicza 11, 30-348 Krakow, Poland