English

Current-based RF charge sensing in a carbon nanotube

Mesoscale and Nanoscale Physics 2026-07-30 v1

Abstract

Ultra-sensitive charge detection is a widely used tool for quantum electronics with applications in quantum information processing and in probing the physics of condensed matter systems. Existing approaches require either an impedance-matched resonant circuit, or millimeter-scale proximity between amplifier and sample, both adding complexity and constraining device design. In this work, we introduce a current-mode charge sensor in a suspended carbon nanotube, operating at the 1.251.25 MHz resonance of an RLC tank circuit and achieving a charge sensitivity of 0.15 μe/Hz0.15~\mu e/\sqrt{\mathrm{Hz}}. We utilize it to measure a double quantum dot (DQD) electrostatically defined in the same nanotube, revealing a highly regular charge stability diagram. We perform single-shot readout of the DQD charge state at an integration time of 3.56 μs3.56~\mu\mathrm{s}, without any false assignments over 10710^{7} measurements and a signal-to-noise ratio of 17 exceeding the state of the art.

Cite

@article{arxiv.2607.28313,
  title  = {Current-based RF charge sensing in a carbon nanotube},
  author = {Marta Cagetti and Stefan Forstner and Victor Champain and Roger Tormo-Queralt and Christoffer B. Møller and Sergio L. De Bonis and Chandan Samanta and Elsa Vázquez-Rodriguez and Eneko Mateos-Madinabeitia and David A. Czaplewski and Adrian Bachtold},
  journal= {arXiv preprint arXiv:2607.28313},
  year   = {2026}
}