In situ scanning gate imaging of individual quantum two-level system defects in live superconducting circuits.

ABSTRACT: The low-temperature physics of structurally amorphous materials is governed by low-energy two-level system (TLS) defects. Being impervious to most traditional condensed matter probes, the exact origin and nature of TLS remain elusive. Recent advances toward realizing stable high-coherence quantum computing platforms have increased the importance of studying TLS in solid-state quantum circuits, as they are a persistent source of decoherence and instability. Here, performing scanning gate microscopy on a live superconducting NbN resonator at millikelvin temperatures, we locate individual TLS, directly revealing their microscopic nature. Mapping and visualizing the most detrimental TLS in the bath pinpoints the dominant sources of ubiquitous 1/f dielectric noise and energy relaxation.

SUBMITTER: Hegedus M 

PROVIDER: S-EPMC12042869 | biostudies-literature | 2025 May

REPOSITORIES: biostudies-literature