ELFT HÍRADÓ

[Szeminárium koordinátor <szfi-seminar AT wigner.mta.hu>]

SZFI SeminarNémet NikolettUniversity of Auckland (host: Vukics András)Coupled 
Nanofibre Fabry-Perot Cavity-QEDTuesday, 10 March 2020, 10:00, KFKI Campus, 
Bldg. 1, 2nd floor, Conference RoomRecently, 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) 
 Minden érdeklődőt szívesen látunk! - Everyone is welcome to 
attend.Róbert Juhászszfi-seminar AT wigner.mta.hu