SZFI Szeminárium
Német Nikolett
(University of Auckland, vendéglátó: Vukics András)
Coupled Nanofibre Fabry-Perot Cavity-QED

Recently, experiments in the group of Takao Aoki at Waseda University in Japan have demonstrated coherent coupling of two nanofibre cavity-quantum electrodynamic (QED) systems separated by a distance of more than a meter [1]. Transmission spectra show dressed states of the atoms in the two cavities with a normal mode of the cavity/coupling fibre/cavity system that is dark in the coupling fibre, hence offering a robust, coherent channel between the two distant atom-cavity systems. Complementary to this, another experiment [2] has demonstrated the existence of a dressed state of the distant atoms with only the coupling fibre, i.e., a dressed state that is dark in the two cavity modes. These phenomena are qualitatively well described by a relatively simple quantum optical model based upon treating the cavity and coupling fibre fields as single modes, with losses accounted for in a master equation approach. However, the long lengths of the cavities and the relatively low reflectivities of the (fibre Bragg grating) mirrors mean that the single-mode picture can be limited in its applicability to this system. As an alternative, one can develop a travelling-wave picture and transfer (or scattering) matrix approach that incorporates all modes of the fibre system, giving an improved model of the transmission properties [3]. A drawback of the transfer matrix approach is that it is linear and only appropriate for weak coherent driving. In order to have a fully quantum description, we have implemented a numerical method based on tensor-networks, which handles the two-way cascade represented by the connecting fibre in a similar fashion to a coherent time-delayed feedback system [4]. In this presentation I will sum up the experimental results and theoretical methods described above.

[1] S. Kato, N. Német, K. Senga, S. Mizukami, X. Huang, S. Parkins and T. Aoki, Nat. Commun. 10, 1160 (2019)
[2] D. H. White, S. Kato, N. Német, S. Parkins and T. Aoki, Phys. Rev. Lett. 122, 253603 (2019)
[3] N. Német, D. H. White, S. Kato, S. Parkins and T. Aoki, arXiv:1912.01755
[4] H. Pichler, and P. Zoller, PRL, 116, 093601 (2016)

2021. május 8. szombat, 10.00
Wigner FK SZFI, 1. ép. 1. em. nagy előadóterem