Single-photon scattering in a giant-molecule waveguide-QED system

Abstract

We study the coherent single-photon scattering in a one-dimensional waveguide coupled to a giant artificial molecule consisting of two coupled giant atoms. Since each giant atom couples to the waveguide via two coupling points, the couplings of the molecule with the waveguide have three different coupling configurations: the separated-, braided-, and nested-coupling cases. We obtain the exact expressions of the single-photon transmission and reflection amplitudes with the real-space approach. It is found that the behavior of the scattering spectra depends on the phase shift between two neighboring coupling points, the coupling configuration, and the coupling between the two giant atoms. Concretely, we study the photon scattering in both the Markovian and non-Markovian regimes, in which the photon propagating time between two neighboring coupling points is neglected and considered, respectively. Under the Markovian limit, the asymmetric Fano lineshapes in different coupling configurations of the giant-molecule waveguide-QED system can be obtained by choosing proper phase shift, and the transmission window can be adjusted by the coupling strength between the two giant atoms in these three coupling configurations. In particular, multiple reflection peaks and dips in these configurations are revived in the non-Markovian regime. This work will pave the way for the study of controllable singlephoton devices based on the giant-molecule waveguide-QED systems.

Superconducting giant atom waveguide QED: Quantum Zeno and Anti-Zeno effects in ultrastrong coupling regime

“…This nonlocal coupling leads to lots of otherwise nonexist phenomenon, such as frequency dependent relaxation and Lamb shift [3], non-Markovian atomic dissipation [4][5][6][7], exotic charity [8,9] as well as the decoherence free interatomic interaction [10,11]. Besides, due to the interference effect, the photon propagation behavior can also be modified by the location or the size of the giant atom [12][13][14][15][16][17][18].…”

Tunable Single-Photon Scattering of a Giant Λ-type Atom in a SQUID-Chain Waveguide

“…In such giant atom systems, many striking effects were discovered [18]. For example, strongly frequency-dependent coupling between giant atoms and bosonic modes can be designed for realizing interference effects [23][24][25][26] between coupling points, which enables electromagnetically induced transparency (EIT) in a ladder configuration [27]. When the distance of the coupling points is too large, the Markovian approximation can no longer be applied to the whole system.…”