Observation of directly interacting coherent two-level systems in a solid

Abstract

Parasitic two-level tunneling systems originating from structural material defects affect the functionality of various microfabricated devices by acting as a source of noise. In particular, superconducting quantum bits may be sensitive to even single defects when these reside in the tunnel barrier of the qubit's Josephson junctions, and this can be exploited to observe and manipulate the quantum states of individual tunneling systems. Here, we detect and fully characterize a system of two strongly interacting defects using a novel technique for high-resolution spectroscopy. Mutual defect coupling has been conjectured to explain various anomalies of glasses, and was recently suggested as the origin of low frequency noise in superconducting devices. Our study provides conclusive evidence of defect interactions with full access to the individual constituents, demonstrating the potential of superconducting qubits for studying material defects. All our observations are consistent with the assumption that defects are generated by atomic tunneling.

13 pages, 7 figures. Includes supplementary material

References in corpus (8)

• State tomography of capacitively shunted phase qubits with high fidelity
• Measuring the temperature dependence of individual two-level systems by direct coherent control
• Microscopic Model of Critical Current Noise in Josephson Junctions
• Delocalised oxygen as the origin of two-level defects in Josephson junctions
• Quantitative evaluation of defect-models in superconducting phase qubits
• Tunneling Spectroscopy of Two-level Systems Inside Josephson Junction
• Microscopic model of critical current noise in Josephson-junction qubits: Subgap resonances and Andreev bound states
• $T_1$-Echo Sequence - Protecting the state of a qubit in the presence of coherent interaction

Cited by in corpus (11)

• Quantum Sensors for Microscopic Tunneling Systems
• Low-Loss Superconducting Nanowire Circuits Using a Neon Focused Ion Beam
• Transmission-line resonators for the study of individual two-level tunneling systems
• Generation of Ultra-Low Power Phononic Combs
• Driven-state relaxation of a coupled qubit-defect system in spin-locking measurements
• Protecting superconducting qubits from phonon mediated decay
• Development of transmon qubits solely from optical lithography on 300mm wafers
• Mesoscopic Quantum Thermo-mechanics: a new frontier of experimental physics
• Material matters in superconducting qubits
• Quantum synchronization in disordered superconducting metamaterials
• Superconducting on-chip spectrometer for mesoscopic quantum systems