Probing individual tunneling fluctuators with coherently controlled tunneling systems

Abstract

Josephson junctions made from aluminium and its oxide are the most commonly used functional elements for superconducting circuits and qubits. It is generally known that the disordered thin-film AlOx contains atomic tunneling systems. Coherent tunneling systems may couple strongly to a qubit via their electric dipole moment, giving rise to spectral level repulsion. In addition, slowly fluctuating tunneling systems are observable when they are located close to coherent ones and distort their potentials. This interaction causes telegraphic switching of the coherent tunneling systems' energy splitting. Here, we measure such switching induced by individual fluctuators on time scales from hours to minutes using a superconducting qubit as a detector. Moreover, we extend the range of measurable switching times to millisecond scales by employing a highly sensitive single-photon qubit swap spectroscopy and statistical analysis of the measured qubit states.

References in corpus (6)

• Realizing Rapid, High-Fidelity, Single-Shot Dispersive Readout of Superconducting Qubits
• State tomography of capacitively shunted phase qubits with high fidelity
• Observation of directly interacting coherent two-level systems in a solid
• Generalized Tunneling Model for TLS in amorphous materials and its predictions for their dephasing and the noise in superconducting microresonators
• Measuring the temperature dependence of individual two-level systems by direct coherent control
• Probing nanocrystalline grain dynamics in nanodevices

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• Quantum Sensors for Microscopic Tunneling Systems
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• Enhancing the Coherence of Superconducting Quantum Bits with Electric Fields
• Probing hundreds of individual quantum defects in polycrystalline and amorphous alumina
• Dynamical Decoupling of Quantum Two-Level Systems by Coherent Multiple Landau-Zener Transitions
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• Decoherence induced by a sparse bath of two-level fluctuators: peculiar features of $1/f$ noise in high-quality qubits
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• Towards a general framework of Randomized Benchmarking incorporating non-Markovian Noise
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• Theory of nonlinear microwave absorption by interacting two-level systems
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• Averting multi-qubit burst errors in surface code magic state factories
• Dynamic phases induced by two-level system defects on driven qubits
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