Carbon Nanotube Electromechanical Oscillators: where photons, phonons and electrons meet

Résumé :

Achieving strong mechanical nonlinearities, minimally invasive detection, and control at the few-phonon level is a central challenge in the development of mechanical oscillators for quantum technologies, including quantum information processing (1,2), precision sensing (3), and tests of quantum mechanics (4,5). In our group, we aim to realize these capabilities using suspended carbon-nanotube mechanical oscillators coupled to electronic quantum dots. In this talk, I will present results obtained with a device operating in the exotic dispersive ultrastrong-coupling regime (6,7), where the interaction strength between a nanotube mechanical oscillator and a double-quantum-dot electronic two-level system (DQD-ETLS) exceeds the bare energy of the oscillator. In this regime, we demonstrate a mechanical Kerr oscillator with an anharmonicity exceeding the state of the art for mechanical systems by four orders of magnitude (8). We read out the mechanical states using a superconducting cavity coupled to the square displacement (x²) of the oscillator (8), paving the way towards future quantum non-demolition (QND) cavity-based readout of mechanical Fock states (9). I will also show that the decay and decoherence rates of our ETLS charge qubit outperforms the current state of the art for 2DEG-based systems, reaching the highest coherence values ever measured in a charge-based DQD-ETLS (10).

1 A. D. O’Connell, et al. Nature 464 (2010)
2 Y. Yang, et al. A mechanical qubit, 386 (6723) (2024)
3 F. Pistolesi, et al. Phys. Rev. X, 11, 031027 (2021)
4 M.F. Gely et al., AVS Quantum Sci. 3, 035601 (2021)
5 Oriol Romero-Isart. et, al. Physical Review A, 84 (2011)
6 C. Samanta et al, Nat. Phys. 19 (2023)
7 P. Forn-Díaz et al., Rev. Mod. Phys (2019)
8 C.B. Moller*, R.Tormo-Queralt* (under review) 9 P. Arrangoiz-Ariola, Nature volume 571 (2019)
10 P. Scarlino Phys. Rev. Lett. 122, 206802 (2019)

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Contact : equipe-seminaires-nano@listes.grenoble.cnrs.fr