Non-Markovian nonreciprocal interactions in waveguide-based systems

H. Yi, T. Z. Luan, W. Y. Hu +4 more

Xin Wang, Qing‐Yang Qiu, Kai‐Wei Huang +1 more

We study nonreciprocal single-photon scattering in a giant-spin-ensemble (GSE)--waveguide magnonics system where the GSE constructed by a yttrium iron garnet sphere interacts twice with the waveguide via two separated coupling points. It is shown that the generation of nonreciprocity arises from the synergy of the breaking of time-reversal symmetry induced by the chiral coupling and the intrinsic dissipation of the magnon mode in the case of a single waveguide. The accumulated phase caused by the photon propagating between coupling points can be a powerful tool to control nonreciprocity due to quantum interference effects. Compared to the Markovian regime, single-photon transmission exhibits peculiarly nonreciprocal properties in the non-Markovian regime. Multiple narrow nonreciprocal transmission windows are observed. Non-Markovianity can break the decoupling phenomenon of the Markovian regime and non-Markovianity-induced nonreciprocity is demonstrated. We extend the study of nonreciprocity to the GSE coupled to a double-waveguide structure to explore the design of quantum devices. A high-efficiency and tunable multifrequency single-photon targeted router and circulator with narrow operational bandwidth are achieved. Our results provide an effective avenue for single-photon manipulation and have potential applications in designing magnon-based quantum devices and constructing an integrated quantum network.

Z. Kanokov

Dariusz Chruściński, Andrzej Kossakowski

Xue-jian Sun, Wenxiao Liu, Hao Chen +1 more

Abstract We investigate the single-photon scattering properties of a driven three-level giant atom chirally coupled to two waveguides simultaneously in both the Markovian and the non-Markovian regimes. It is shown that under the Markovian limit, the chiral photon-atom interactions enable nonreciprocal scattering in a single waveguide and targeted photon routing with a probability of 100% in two waveguides, while the presence of the driving field and the giant atom structure introduce a more tunable parameter to manipulate the single-photon scattering behaviors. We also examine how the non-reciprocity and routing capability are influenced by the imperfect chirality and the atomic dissipation. In the non-Markovian regime, we show that the scattering behaviors are more complicated. The non-Markovicity induced non-reciprocity and photon routing are demonstrated in this paper. We believe that those results have potential applications in quantum network engineering.

Yue Chang

Chiral interactions enable directional control of quantum light, providing new routes for nonreciprocal photon dynamics. While previous studies focused on single photon regimes, this work explores the non-Markovian multiphoton regime in a giant nonlinear system nonlocally coupled to a one-dimensional waveguide, with a tunable phase difference breaking parity symmetry. We show that single-photon transport remains reciprocal, but multiphoton dynamics become chiral, generating direction-dependent higher-order correlations and enabling deterministic creation of multiphoton states with nontrivial statistics from a single input direction, even under strong dissipation. The non-Markovian nature allows tuning of transmitted photon statistics via the coupling-point separation. At a specific phase, internal dynamics become Markovian while output photons retain non-Markovian features. Under strong coherent driving, we uncover nonreciprocal dissipative phase transitions and demonstrate how non-Markovianity shapes the critical response. This framework offers a general strategy for controlling chiral multiphoton dynamics in nonlocally coupled waveguide QED systems. Chiral light-matter interactions offer directional control of quantum states. This work demonstrates that a giant quantum emitter with tunable nonlocal coupling to a waveguide enables direction-dependent multiphoton correlations and dissipative phase transitions, providing a route to engineer non-Markovian chiral dynamics.