Dragan Mihailović [Jozef Stefan Institute]

Abstract: After a phase transition, non-equilibrium many body systems can end up in diverse emergent states that are textured on different time- and length-scales, the eventual outcome being determined by ‘quantum Darwinism’. Mesoscopic states that are created in the process are of particular interest because they act as electron traps and act as sources of noise. Remarkably, we show that it is possible to measure individual electronic motion within such traps in real time with a high-speed scanning tunnelling microscope. The measurement yields classical movies of the spatially fluctuating density of electronic states whose electronic configurations are determined by quantum probabilities governed by non-local symmetry and global topological protection. Time-series measurements show that the electrons exhibit pseudo-periodic trajectories which generate correlated telegraph noise that cannot be explained by conventional quasiparticle interference.

This demonstration paves the way for real-time studies of microscopic dynamics in metastable mesoscopic states of quantum materials that may be particularly useful for pinpointing sources of noise in superconducting quantum devices for example.