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arXiv · 2605.12257

Probing charge noise in bilayer graphene quantum dots by Landau-Zener-St\"uckelberg-Majorana spectroscopy

Katrin Hecker·Samuel Möller·Tobias Deußen·Hubert Dulisch·Luca Banszerus·Kenji Watanabe·Takashi Taniguchi·Christian Volk·Christoph Stampfer
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Abstract

Charge noise is an important factor limiting qubit coherence and relaxation in solid-state devices. In bilayer graphene (BLG) quantum dots, recently established as a promising platform for spin- and valley-based qubits, both the origin and magnitude of charge noise remain largely unexplored. Here, we investigate high-frequency charge noise using Landau-Zener-St\"uckelberg-Majorana (LZSM) interference spectroscopy. We study a single-particle charge qubit formed in a BLG double quantum dot at frequencies between 5 and 10 GHz and extract a noise spectral density $S_\varepsilon$ on the order of 0.5-0.9 neV$/\sqrt{\mathrm{Hz}}$. This is comparable to values reported for III-V semiconductor platforms and silicon. From the temperature and frequency dependence of the charge qubit decoherence, we conclude that thermal (Johnson) noise or electron-phonon coupling dominates over two-level fluctuators.

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Katrin Hecker, Samuel Möller, Tobias Deußen, Hubert Dulisch, Luca Banszerus, Kenji Watanabe, Takashi Taniguchi, Christian Volk, Christoph Stampfer. 2026-05-12. Probing charge noise in bilayer graphene quantum dots by Landau-Zener-St\"uckelberg-Majorana spectroscopy. https://arxiv.org/abs/2605.12257

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