Vacuum-field-induced THz transport gap in a carbon nanotube quantum dot

F Valmorra,M M Desjardins,A Cottet,M R Delbecq,T Kontos,K Yoshida,L C Contamin,T Cubaynes,S Messelot,J Mangeney,S Balibar,Z Leghtas,K Hirakawa,J Tignon,S Massabeau,S Dhillon,M C Dartiailh

doi:10.1038/s41467-021-25733-x

Abstract

The control of light-matter interaction at the most elementary level has become an important resource for quantum technologies. Implementing such interfaces in the THz range remains an outstanding problem. Here, we couple a single electron trapped in a carbon nanotube quantum dot to a THz resonator. The resulting light-matter interaction reaches the deep strong coupling regime that induces a THz energy gap in the carbon nanotube solely by the vacuum fluctuations of the THz resonator. This is directly confirmed by transport measurements. Such a phenomenon which is the exact counterpart of inhibition of spontaneous emission in atomic physics opens the path to the readout of non-classical states of light using electrical current. This would be a particularly useful resource and perspective for THz quantum optics.

Highlights

The control of light-matter interaction at the most elementary level has become an important resource for quantum technologies
Despite the fact that the electrical coupling is very often described by a dipoleelectric field coupling, it is important to stress that the microscopic origin of this phenomenon is a coupling of the electron density to the electric field of the form[4]: Z
Where ^ρðrÞ is the electronic density, v(r) the distribution function of the electric field and Vrms(a + a†) is the quantized electric field corresponding to a cavity mode of frequency fcav, with Vrms the amplitude of the vacuum fluctuations

Summary

Introduction

The control of light-matter interaction at the most elementary level has become an important resource for quantum technologies. The resulting light-matter interaction reaches the deep strong coupling regime that induces a THz energy gap in the carbon nanotube solely by the vacuum fluctuations of the THz resonator. This is directly confirmed by transport measurements. In the case of strong hybridization between light and matter, one expects changes in the electronic transport properties This has recently attracted considerable interest in the limit of many particles or collective modes[10–15]. The large particle density helps to reach strong light-matter hybridization This contrasts with a single electron occupying a single orbital that we study here. This situation can be understood with a simple tunneling argument

Methods

Results

Conclusion