Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:2502.10121 · Physical Review A

Nonreciprocal routing induced by chirality in an atom-dimer waveguide-QED system

Shi-Yu Liu, Lin-Lin Jiang, Hai Zhu, Jie‐Qiao Liao, Jin‐Feng Huang

Published Nov 12, 2025• 3 citations
arXivHTMLPDF

Abstract

The implementation of quantum routers is an important and desired task in quantum information science, since quantum routers are important components of quantum networks. Here, we propose a scheme for implementing single-photon routers in a waveguide-QED system, which consists of two coupled two-level atoms coupled to two waveguides to form a four-port quantum device. We obtain the exact analytical expressions of the single-photon scattering amplitudes using the real-space method. By taking the propagating time of photons between two coupling points into account or not, we consider the system working in the Markovian and non-Markovian regimes, respectively. In addition, we introduce the chiral coupling, which breaks the symmetry of the waveguide model, to manipulate the transmission of single photons. We find that when the system works in the non-Markovian regime, the single photon can be transmitted on demand by adjusting the asymmetry coefficient. More interestingly, the complete single-photon routing in this device does not require an ideal chiral coupling, loosening the photon transport conditions. This work will motivate the studies concerning the nonreciprocal and chiral quantum devices in the waveguide-QED platform.

DOI
10.1103/14mw-23wm

Related papers

Chiral and nonreciprocal single-photon scattering in a chiral-giant-molecule waveguide-QED system

Juan Zhou, Xian‐Li Yin, Jie‐Qiao Liao

We study chiral and nonreciprocal single-photon scattering in a chiral-giant-molecule waveguide-QED system. Here, the giant molecule consists of two coupled giant atoms, which interact with two linear waveguides, forming a four-port quantum device. We obtain the exact analytical expressions of the four scattering amplitudes using a real-space method. Under the Markovian limit, we find that the single-photon scattering behavior is determined by the coupling strength between the giant atoms and the waveguides, the coupling strength between the two giant atoms, and the nondipole effect caused by the phase accumulation of photons traveling between the coupling points. It is also found that chiral and nonreciprocal single-photon scattering can be realized by introducing the chiral coupling to break the symmetry in the coupling configuration between the giant molecule and the waveguides. In addition, an ideal chiral emitter-waveguide coupling enables a directional single-photon routing. In the non-Markovian regime, the scattering spectra are characterized by more abundant structures with multiple peaks and dips. In particular, we demonstrate that the non-Markovian retarded effect can induce the nonreciprocal single-photon scattering. Our results have potential applications in the design of optical quantum devices involving giant atoms, which can provide an efficient platform for studying chiral quantum optics.

arXiv:2306.10957•Physical Review A•Jun 13, 2023•65 citations

Phase-engineered single-photon quantum router and chiral scattering in waveguide-coupled cavity-QED system

Liming Yang, Z H Zhu, Yi‐Qi Zhang +1 more

Abstract We present a theoretical study of controlled single-photon routing in a cavity-quantum electrodynamics system coupled to dual waveguides, where each cavity embedding with a two-level atom mediates photon transport between two channels. The proposed system achieves enhanced routing performance through tailored phase-dependent cavity–waveguide couplings that generate optimized quantum interference patterns. Using a real-space formalism, we derive analytical expressions for single-photon scattering amplitudes and identify optimal conditions for maximum routing efficiency. Our analysis shows that targeted routing with near-unity efficiency can be realized by precisely manipulating both the accumulated phase and differential phase shift, while the atom–cavity coupling strength enables frequency-selective tunability. Furthermore, we demonstrate engineered nonreciprocal transmission and chiral scattering, enabling deterministic control over photonic propagation direction. This phase-tunable protocol establishes a scalable platform for quantum network implementation and enables novel functionalities in photonic quantum information processing.

Laser Physics Letters•Sep 1, 2025•0 citations

Photon routing based on non-chiral interaction between atoms and waveguides

Wang-Rui Zhang, Tao Shui, Yilou Liu +2 more

Abstract The photon router plays an essential role in the optical quantum network. However, conventional routers generally couple photons chirally into waveguides to achieve complete transmission from the input port to the required port. Here, we use non-chiral photon-atom interactions for targeted routing. The system consists of two V-type three-level atoms and two parallel waveguides. In addition, the two atoms are driven by external coherent fields, respectively. With a real-space Hamiltonian, the probability of photon transmitted to four ports can be obtained. The study shows that a single photon input from the left port of the waveguide-a can be deterministically transferred to any of the four ports of the two waveguides by adjusting the detuning of the atom and the driving field on the atom, as well as the distance between the two atoms.

Laser Physics Letters•Nov 30, 2021•3 citations

Tunable single-photon nonreciprocal scattering and targeted router in a giant atom-waveguide system with chiral couplings

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.

Communications in Theoretical Physics•Jan 30, 2023•16 citations

Single-photon scattering in a two-level giant atom-dual waveguide coupled system based on local coupling phase regulation

Zhonghua ZHU, CHEN Keke, Yuqing Zhang +6 more

This work is to investigate the single-photon scattering in a waveguide quantum electrodynamics system consisting of two dipole-coupled giant atoms, each interacting with a separate one-dimensional infinite waveguide at two distinct coupling points. Our primary objective is to establish a theoretical framework for manipulating photon propagation paths via quantum interference induced by multiple coupling points and local phase engineering. Unlike traditional chiral coupling schemes, an innovative method, in which the coupling phases are designed locally at each atom-waveguide interface, is used to achieve effective chiral coupling, thereby introducing novel quantum interference mechanisms. Using a real-space approach, we derive analytical expressions for four-port scattering amplitudes. We establish the conditions for achieving perfect directional routing to any output port and demonstrate the coherent control mechanisms implemented by geometric and local coupled phases. Continuous frequency tunability is primarily achieved through dipole-dipole interaction, and finely tuned through the accumulated phase and local coupling phases. Local phase differences precisely regulate port-specific probability distributions within the waveguides while preserving total routing efficiency. Furthermore, we elucidate the mechanisms of nonreciprocal transport and chiral scattering. The analysis reveals different governing principles: perfect nonreciprocity arises from the interplay of the accumulated phase, local coupling phases, photon-atom detuning, and dipole-dipole interaction. In contrast, perfect chiral scattering depends entirely on the accumulated phase and local coupling phases, and is independent of detuning. Notably, under the phase-matching conditions, the system achieves both perfect chiral and directional routing, and realizes frequency-selective path-asymmetric photon control. These findings provide a comprehensive framework for manipulating quantum interference in multi-atom waveguide systems, highlighting applications in quantum information processing, including tunable single-photon routers, isolators, and chiral quantum nodes. By implementing superconducting circuits, the local phase can be dynamically adjusted, thus proving the feasibility of the experiment.

Acta Physica Sinica•Jan 1, 2025•2 citations

Targeted quantum routing of single photons in a giant-atom waveguide-QED system

Yong Wang, Wenan Li, Yuan Chen

In this paper, we propose a single-photon routing scheme using a hybrid system, where a two-level giant atom is coupled to a pair of one-dimensional coupled-resonator waveguides. Using the discrete-coordinate scattering approach, exact expressions of the four scattering coefficients are obtained, and the single-photon routing properties are studied. We find that the single-photon routing properties are closely related to the size of the giant atom, the coupling strength between the giant atom and waveguides, and the phase difference between two coupled channels of the atom-upper (lower) waveguide. Without considering the effect of phases of the atom-waveguide coupling coefficients, the probability for a single-photon routing from one waveguide to the other does not exceed $50%$. However, by properly selecting coupling points between the giant atom and two waveguides, and the phase difference between two atom-upper (lower) waveguide coupling coefficients, a single photon can be transferred from the input port to an arbitrarily selected output port deterministically, i.e., with $100%$ probability. It is also found that chiral and nonreciprocal single-photon scattering can be realized in our model by properly adjusting the phase difference between two atom-upper (lower) waveguide coupled channels. Our paper offers a promising route towards achieving tunable single-photon routing and constructing optical scalable quantum networks.

Physical Review A•Apr 18, 2025•13 citations
The implementation of quantum routers is an important and desired task in quantum information science, since quantum routers are important components of quantum networks. Here, we propose a scheme for implementing single-photon routers in a waveguide-QED system, which consists of two coupled two-level atoms coupled to two waveguides to form a four-port quantum device. We obtain the exact analytical expressions of the single-photon scattering amplitudes using the real-space method. By taking the propagating time of photons between two coupling points into account or not, we consider the system working in the Markovian and non-Markovian regimes, respectively. In addition, we introduce the chiral coupling, which breaks the symmetry of the waveguide model, to manipulate the transmission of single photons. We find that when the system works in the non-Markovian regime, the single photon can be transmitted on demand by adjusting the asymmetry coefficient. More interestingly, the complete single-photon routing in this device does not require an ideal chiral coupling, loosening the photon transport conditions. This work will motivate the studies concerning the nonreciprocal and chiral quantum devices in the waveguide-QED platform.
We study chiral and nonreciprocal single-photon scattering in a chiral-giant-molecule waveguide-QED system. Here, the giant molecule consists of two coupled giant atoms, which interact with two linear waveguides, forming a four-port quantum device. We obtain the exact analytical expressions of the four scattering amplitudes using a real-space method. Under the Markovian limit, we find that the single-photon scattering behavior is determined by the coupling strength between the giant atoms and the waveguides, the coupling strength between the two giant atoms, and the nondipole effect caused by the phase accumulation of photons traveling between the coupling points. It is also found that chiral and nonreciprocal single-photon scattering can be realized by introducing the chiral coupling to break the symmetry in the coupling configuration between the giant molecule and the waveguides. In addition, an ideal chiral emitter-waveguide coupling enables a directional single-photon routing. In the non-Markovian regime, the scattering spectra are characterized by more abundant structures with multiple peaks and dips. In particular, we demonstrate that the non-Markovian retarded effect can induce the nonreciprocal single-photon scattering. Our results have potential applications in the design of optical quantum devices involving giant atoms, which can provide an efficient platform for studying chiral quantum optics.
Abstract We present a theoretical study of controlled single-photon routing in a cavity-quantum electrodynamics system coupled to dual waveguides, where each cavity embedding with a two-level atom mediates photon transport between two channels. The proposed system achieves enhanced routing performance through tailored phase-dependent cavity–waveguide couplings that generate optimized quantum interference patterns. Using a real-space formalism, we derive analytical expressions for single-photon scattering amplitudes and identify optimal conditions for maximum routing efficiency. Our analysis shows that targeted routing with near-unity efficiency can be realized by precisely manipulating both the accumulated phase and differential phase shift, while the atom–cavity coupling strength enables frequency-selective tunability. Furthermore, we demonstrate engineered nonreciprocal transmission and chiral scattering, enabling deterministic control over photonic propagation direction. This phase-tunable protocol establishes a scalable platform for quantum network implementation and enables novel functionalities in photonic quantum information processing.
Abstract The photon router plays an essential role in the optical quantum network. However, conventional routers generally couple photons chirally into waveguides to achieve complete transmission from the input port to the required port. Here, we use non-chiral photon-atom interactions for targeted routing. The system consists of two V-type three-level atoms and two parallel waveguides. In addition, the two atoms are driven by external coherent fields, respectively. With a real-space Hamiltonian, the probability of photon transmitted to four ports can be obtained. The study shows that a single photon input from the left port of the waveguide-a can be deterministically transferred to any of the four ports of the two waveguides by adjusting the detuning of the atom and the driving field on the atom, as well as the distance between the two atoms.
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.
This work is to investigate the single-photon scattering in a waveguide quantum electrodynamics system consisting of two dipole-coupled giant atoms, each interacting with a separate one-dimensional infinite waveguide at two distinct coupling points. Our primary objective is to establish a theoretical framework for manipulating photon propagation paths via quantum interference induced by multiple coupling points and local phase engineering. Unlike traditional chiral coupling schemes, an innovative method, in which the coupling phases are designed locally at each atom-waveguide interface, is used to achieve effective chiral coupling, thereby introducing novel quantum interference mechanisms. Using a real-space approach, we derive analytical expressions for four-port scattering amplitudes. We establish the conditions for achieving perfect directional routing to any output port and demonstrate the coherent control mechanisms implemented by geometric and local coupled phases. Continuous frequency tunability is primarily achieved through dipole-dipole interaction, and finely tuned through the accumulated phase and local coupling phases. Local phase differences precisely regulate port-specific probability distributions within the waveguides while preserving total routing efficiency. Furthermore, we elucidate the mechanisms of nonreciprocal transport and chiral scattering. The analysis reveals different governing principles: perfect nonreciprocity arises from the interplay of the accumulated phase, local coupling phases, photon-atom detuning, and dipole-dipole interaction. In contrast, perfect chiral scattering depends entirely on the accumulated phase and local coupling phases, and is independent of detuning. Notably, under the phase-matching conditions, the system achieves both perfect chiral and directional routing, and realizes frequency-selective path-asymmetric photon control. These findings provide a comprehensive framework for manipulating quantum interference in multi-atom waveguide systems, highlighting applications in quantum information processing, including tunable single-photon routers, isolators, and chiral quantum nodes. By implementing superconducting circuits, the local phase can be dynamically adjusted, thus proving the feasibility of the experiment.
In this paper, we propose a single-photon routing scheme using a hybrid system, where a two-level giant atom is coupled to a pair of one-dimensional coupled-resonator waveguides. Using the discrete-coordinate scattering approach, exact expressions of the four scattering coefficients are obtained, and the single-photon routing properties are studied. We find that the single-photon routing properties are closely related to the size of the giant atom, the coupling strength between the giant atom and waveguides, and the phase difference between two coupled channels of the atom-upper (lower) waveguide. Without considering the effect of phases of the atom-waveguide coupling coefficients, the probability for a single-photon routing from one waveguide to the other does not exceed 5050%50. However, by properly selecting coupling points between the giant atom and two waveguides, and the phase difference between two atom-upper (lower) waveguide coupling coefficients, a single photon can be transferred from the input port to an arbitrarily selected output port deterministically, i.e., with 100100%100 probability. It is also found that chiral and nonreciprocal single-photon scattering can be realized in our model by properly adjusting the phase difference between two atom-upper (lower) waveguide coupled channels. Our paper offers a promising route towards achieving tunable single-photon routing and constructing optical scalable quantum networks.