RT Journal Article T1 Ultrastrong coupling between electron tunneling and mechanical motion A1 Tabanera Bravo, Jorge A1 Rodríguez Parrondo, Juan Manuel A1 otros, ... AB The ultrastrong coupling of single-electron tunneling and nanomechanical motion opens exciting opportunities to explore fundamental questions and develop new platforms for quantum technologies. We have measured and modeled this electromechanical coupling in a fully suspended carbon nanotube device and report a ratio of gm/omega m = 2.72 +/- 0.14, where gm/2 pi = 0.80 +/- 0.04 GHz is the coupling strength and omega m/2 pi = 294.5 MHz is the mechanical resonance frequency. This is well within the ultrastrong coupling regime and the highest among all other electromechanical platforms. We show that, although this regime was present in similar fully suspended carbon nanotube devices, it went unnoticed. Even higher ratios could be achieved with improvement on device design. PB American Physical Society SN 2643-1564 YR 2022 FD 2022-12-07 LK https://hdl.handle.net/20.500.14352/72951 UL https://hdl.handle.net/20.500.14352/72951 LA eng NO Artículo firmado por 12 autores. We acknowledge useful discussions with M. Woolleyand F. Pistolesi and thank Serkan Kaya for his helpin the fabrication of the device. This research was supported by Grant No. FQXi-IAF19-01 from the Foundational Questions Institute Fund, a donor advised fund of Silicon Valley Community Foundation. N.A. acknowledges the support from the Royal Society, EPSRC Platform Grant (Grant No. EP/R029229/1), from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (Grant Agreement No. 948932), and from Templeton World Charity Foundation. A.A. acknowledges the support of the Foundational Questions Institute Fund (Grant No. FQXi-IAF19-05), the Templeton World Charity Foundation, Inc (Grant No.TWCF0338) and the ANR Research Collaborative Project "Qu-DICE" (Grant No. ANR-PRC-CES47). J.T. and J.M.R.P.acknowledge financial support from the Spanish Government (Grant Contract, FIS-2017-83706-R). J.A. acknowledges support from EPSRC (Grant No. EP/R045577/1) and the Royal Society. J.M. acknowledges funding from the Vetenskapsradet, Swedish VR (Project No. 2018-05061). NO Foundational Questions Institute Fund NO Silicon Valley Community Foundation NO Royal Society NO EPSRC Platform Grant NO European Research Council (ERC) under the European Union NO Templeton World Charity Foundation NO ANR Research Collaborative Project "Qu-DICE" NO Gobierno de España NO EPSRC NO Vetenskapsradet, Swedish VR DS Docta Complutense RD 17 abr 2025