Superconducting qubit based on a single molecule: the carbon nanotube gatemon

• URL: http://arxiv.org/abs/2503.01978v1
• Date: Mon, 03 Mar 2025 19:00:38 GMT
• Title: Superconducting qubit based on a single molecule: the carbon nanotube gatemon
• Authors: H. Riechert, S. Annabi, A. Peugeot, H. Duprez, M. Hantute, K. Watanabe, T. Taniguchi, E. Arrighi, J. Griesmar, J. -D. Pillet, L. Bretheau,
• Abstract summary: We present the coherent control of a gatemon based on a single molecule, a one-dimensional carbon nanotube.<n>The measured qubit spectrum can be tuned with a gate voltage and reflects the quantum dot behaviour of the nanotube.<n>Our work paves the way for studying microscopic fermionic processes in low-dimensional quantum conductors.
• Score: 0.0
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: Gate-tunable transmon qubits are based on quantum conductors used as weak links within hybrid Josephson junctions. These gatemons have been implemented in just a handful of systems, all relying on extended conductors, namely epitaxial semiconductors or exfoliated graphene. Here we present the coherent control of a gatemon based on a single molecule, a one-dimensional carbon nanotube, which is integrated into a circuit quantum electrodynamics architecture. The measured qubit spectrum can be tuned with a gate voltage and reflects the quantum dot behaviour of the nanotube. Our ultraclean integration, using a hexagonal boron nitride substrate, results in record coherence times of 200ns for such a qubit. Furthermore, we investigate its decoherence mechanisms, thus revealing a strong gate dependence and identifying charge noise as a limiting factor. On top of positioning carbon nanotubes as contenders for future quantum technologies, our work paves the way for studying microscopic fermionic processes in low-dimensional quantum conductors.

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