澳港粤大湾区量子科学中心

Abstract:

Introducing disorder in the superconducting materials has been considered promising to enhance the electromagnetic impedance and realize noise-resilient superconducting qubits. Despite a number of pioneering implementations, the understanding of the correlation between the material disorder and the qubit coherence is still developing. Here, we demonstrate a systematic characterization of fluxonium qubits with the superinductors made by spinodal titanium-aluminum-nitride with varied disorder. From qubit noise spectroscopy, the flux noise and the dielectric loss are extracted as a measure of the coherence properties. Our results reveal that the 1/f flux noise dominates the qubit decoherence around the flux-frustration point, strongly correlated with the material disorder; while the dielectric loss is largely similar under a wide range of material properties. From the flux-noise amplitudes, the areal density () of the phenomenological spin defects and material disorder are found to be approximately correlated by , or effectively. This work has provided new insights on the origin of decoherence channels beyond surface defects and within the superconductors, and could serve as a useful guideline for material design and optimization.

Speaker info:

高然博士现任粤港澳大湾区（广东）量子科学中心研究员（隶属S实验室团队），主要负责适用于超导量子比特的新材料/结构研发、退相干机理的研究、以及超导量子芯片的3D集成技术开发。高然博士本科毕业于复旦大学材料物理专业，2014年获得美国伊利诺伊大学香槟分校材料科学硕士学位，2019年博士毕业于美国加利福尼亚大学伯克利分校。2019年至2024年高然博士于阿里巴巴达摩院量子实验室担任量子科学家，全面参与超导量子芯片的研发工作。