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:2212.13927 · New Journal of Physics

State carving in a chirally-coupled atom-nanophotonic cavity

W. S. Hiew, H. H. Jen

Published Aug 30, 2023• 3 citations
arXivHTMLPDF

Abstract

Abstract Coherent quantum control of multiqubit systems represents one of the challenging tasks in quantum science and quantum technology. Here we theoretically investigate the reflectivity spectrum in an atom-nanophotonic cavity with collective nonreciprocal couplings. In the strong-coupling regime with a high cooperativity, we theoretically predict distinct on-resonance spectral dips owing to destructive interferences of chiral couplings. Due to the well-separated multiple dips in the spectrum, a contrasted reflectivity suggests a new control knob over the desired entangled state preparation in the basis of coupled and uncoupled states from the atoms’ internal hyperfine ground states. We propose to utilize such atom-nanophotonic cavity to quantum engineer the atomic internal states via photon-mediated dipole–dipole interactions in the coupled state and the chirality of decay channels, where the atomic Bell state and W states for arbitrary number of atoms can be tailored and heralded by state carving in the single-photon reflection spectrum. Our results pave the way toward quantum engineering of multiqubit states and offer new opportunities for coherent and scalable multipartite entanglement transport in atoms coupled to nanophotonic devices.

DOI
10.1088/1367-2630/acf518

Related papers

Collective single excitation dynamics in a chirally coupled atomic chain

H. H. Jen

Abstract We theoretically study the collective single excitation dynamics in a chiral-coupled atomic chain with nonreciprocal decay channels. The collective radiation in this one-dimensional (1D) nanophotonics system results from the resonant dipole–dipole interactions in 1D reservoirs, which allow infinite-range couplings between atoms. When a single photon interacts with part of the atomic chain from a side excitation, the long-time decay can be further prolonged when highly correlated states are initially excited. The excitation plateau in the decay process can emerge due to the ordered population exchanges, which presents one distinctive signature of long-range and light-induced atom–atom correlations. Multiple time scales of the decay behaviors also show up due to multiple scattering of light transmissions and reflections in the chain. We further investigate the effect of atomic position fluctuations and find that the cascaded scheme with a unidirectional coupling is more resilient to the fluctuations, while the overall decay constant can be increased due to large deviations. Our results present a fundamental study on the collective excitation dynamics and the light-induced atom–atom correlations in such 1D nanophotonics platforms and offer rich opportunities in potential applications of quantum storage of photons.

arXiv:1903.05352•Journal of Physics B Atomic Molecular and Optical Physics•Jul 27, 2020•7 citations

A nanophotonic quantum interface for atoms in optical tweezers

Dordevic, Tamara

Realizing an efficient quantum optical interface for multi-qubit systems would enable their quantum network integration and the scaling-up of the qubit number via distributed quantum computing. This thesis presents the building blocks for integrating a quantum processor based on a Rydberg atom array with a nanophotonic cavity as an optical interface. In our approach, the integration would be achieved by coherently transporting tweezer-trapped atoms between the cavity near-field and free space. To that end, we first characterize the strong coupling between single photons and atoms enabled by the nanophotonic device. Two 87Rb atoms are trapped in optical tweezers and brought to the cavity near-field, while the cavity is probed in reflection. We observe Purcell enhancement and cavity-mediated interactions between the atoms, corresponding to a single atom cooperativity of C = 70 in the mode center. The qubits are encoded in atomic hyperfine ground states, which have good coherence properties even when the atoms are trapped in the cavity near-field. We create an atomic Bell state by pairing up the coherent manipulation of atomic qubits with a quantum nondemolition measurement, implemented via a single photon reflection from the cavity. Crucial to the integration, we show that single atom coherence and two-atom entanglement can be preserved as the atoms are moved away from the cavity. The nanophotonic dielectric surface can host charges which affect highly polarizable Rydberg states, and this influence is studied by measuring the n = 70 Rydberg state coherence at different distances from the cavity. Our measurements suggest that a Rydberg array may be placed ∼ 200 μm away from a nanophotonic device while retaining high quantum gate fidelities. Our methods can be applied to other atomic species and device geometries, paving the path to quantum networks of Rydberg array processors.

•Jan 1, 2022•0 citations

Strong Coupling of Two Individually Controlled Atoms via a Nanophotonic Cavity

Polnop Samutpraphoot, Tamara Đorđević, Paloma Ocola +4 more

We demonstrate photon-mediated interactions between two individually trapped atoms coupled to a nanophotonic cavity. Specifically, we observe collective enhancement when the atoms are resonant with the cavity and level repulsion when the cavity is coupled to the atoms in the dispersive regime. Our approach makes use of individual control over the internal states of the atoms and their position with respect to the cavity mode, as well as the light shifts to tune atomic transitions individually, allowing us to directly observe the anticrossing of the bright and dark two-atom states. These observations open the door for realizing quantum networks and studying quantum many-body physics based on atom arrays coupled to nanophotonic devices.

arXiv:1909.09108•Physical Review Letters•Feb 11, 2020•115 citations

Atomic excitation trapping in dissimilar chirally coupled atomic arrays

I Gusti Ngurah Yudi Handayana, Chun-Chi Wu, Sumit Goswami +2 more

An atomic array coupled to a one-dimensional nanophotonic waveguide allows photon-mediated dipole-dipole interactions and nonreciprocal decay channels. Such an array possesses many intriguing quantum phenomena due to its distinctive and emergent quantum correlations. In this atom-waveguide quantum system, we theoretically investigate the atomic excitation dynamics and its transport property, specifically at an interface of dissimilar atomic arrays with different interparticle distances. We find that the atomic excitation dynamics is highly dependent on the interparticle distances of dissimilar arrays and the directionality of nonreciprocal couplings. By tuning these parameters, a dominant excitation reflection can be achieved at the interface of the arrays in the single excitation case. We further study two effects on the transport property—of external drive and of single excitation delocalization over multiple atoms—where we manifest a rich interplay between multisite excitation and the relative phase in determining the transport properties. Finally, we present an intriguing trapping effect of atomic excitation by designing multiple zones of dissimilar arrays. Similar to the single excitations, multiple excitations are reflected from the array interfaces and trapped as well, although complete trapping of many excitations together is relatively challenging at long time due to a faster combined decay rate. Our results can provide insights into nonequilibrium quantum dynamics in dissimilar arrays, and they can shed light on confining and controlling quantum registers useful for quantum information processing. Published by the American Physical Society 2024

arXiv:2311.05906•Physical Review Research•Mar 25, 2024•7 citations

Engineering interactions by collective coupling of atom pairs to cavity photons for entanglement generation

Sankalp Sharma, Jan Chwedeńczuk, Tomasz Wasak

Engineering atom-atom interactions is essential both for controlling novel phases of matter and for efficient preparation of many-body entangled states, which are key resources in quantum communication, computation, and metrology. In this work, we propose a scheme to tailor these interactions by coupling driven atom pairs to optical cavity photons via a molecular state in the dispersive regime, resulting in an effective photon-field-dependent potential. As an illustrative example, by analyzing the quantum Fisher information, we show that such induced interactions can generate robust many-body entanglement in two-mode ultracold bosons in an optical cavity. By tuning the photon-induced interactions through the cavity drive, we identify conditions for preparing highly entangled states on timescales that mitigate decoherence due to photon loss. Our results show that entanglement formation rate scales strongly with both photon and atom number, dramatically reducing the timescale compared to bare atomic interactions. We also identify an optimal measurement for exploiting the metrological potential of the atomic state in an interferometric protocol with significant photon losses, saturating the quantum Cramer-Rao lower bound. Furthermore, we show that despite these losses the atomic state exhibits strong Bell correlations. Our results pave the way for engineering atom-atom interactions to study novel phases of light and matter in hybrid atom-photon systems, as well as for tailoring complex quantum states for new quantum technology protocols and fundamental tests of quantum mechanics.

arXiv:2406.14461•Physical Review Research•Feb 20, 2025•2 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
Abstract Coherent quantum control of multiqubit systems represents one of the challenging tasks in quantum science and quantum technology. Here we theoretically investigate the reflectivity spectrum in an atom-nanophotonic cavity with collective nonreciprocal couplings. In the strong-coupling regime with a high cooperativity, we theoretically predict distinct on-resonance spectral dips owing to destructive interferences of chiral couplings. Due to the well-separated multiple dips in the spectrum, a contrasted reflectivity suggests a new control knob over the desired entangled state preparation in the basis of coupled and uncoupled states from the atoms’ internal hyperfine ground states. We propose to utilize such atom-nanophotonic cavity to quantum engineer the atomic internal states via photon-mediated dipole–dipole interactions in the coupled state and the chirality of decay channels, where the atomic Bell state and W states for arbitrary number of atoms can be tailored and heralded by state carving in the single-photon reflection spectrum. Our results pave the way toward quantum engineering of multiqubit states and offer new opportunities for coherent and scalable multipartite entanglement transport in atoms coupled to nanophotonic devices.
Abstract We theoretically study the collective single excitation dynamics in a chiral-coupled atomic chain with nonreciprocal decay channels. The collective radiation in this one-dimensional (1D) nanophotonics system results from the resonant dipole–dipole interactions in 1D reservoirs, which allow infinite-range couplings between atoms. When a single photon interacts with part of the atomic chain from a side excitation, the long-time decay can be further prolonged when highly correlated states are initially excited. The excitation plateau in the decay process can emerge due to the ordered population exchanges, which presents one distinctive signature of long-range and light-induced atom–atom correlations. Multiple time scales of the decay behaviors also show up due to multiple scattering of light transmissions and reflections in the chain. We further investigate the effect of atomic position fluctuations and find that the cascaded scheme with a unidirectional coupling is more resilient to the fluctuations, while the overall decay constant can be increased due to large deviations. Our results present a fundamental study on the collective excitation dynamics and the light-induced atom–atom correlations in such 1D nanophotonics platforms and offer rich opportunities in potential applications of quantum storage of photons.
Realizing an efficient quantum optical interface for multi-qubit systems would enable their quantum network integration and the scaling-up of the qubit number via distributed quantum computing. This thesis presents the building blocks for integrating a quantum processor based on a Rydberg atom array with a nanophotonic cavity as an optical interface. In our approach, the integration would be achieved by coherently transporting tweezer-trapped atoms between the cavity near-field and free space. To that end, we first characterize the strong coupling between single photons and atoms enabled by the nanophotonic device. Two 87Rb atoms are trapped in optical tweezers and brought to the cavity near-field, while the cavity is probed in reflection. We observe Purcell enhancement and cavity-mediated interactions between the atoms, corresponding to a single atom cooperativity of C = 70 in the mode center. The qubits are encoded in atomic hyperfine ground states, which have good coherence properties even when the atoms are trapped in the cavity near-field. We create an atomic Bell state by pairing up the coherent manipulation of atomic qubits with a quantum nondemolition measurement, implemented via a single photon reflection from the cavity. Crucial to the integration, we show that single atom coherence and two-atom entanglement can be preserved as the atoms are moved away from the cavity. The nanophotonic dielectric surface can host charges which affect highly polarizable Rydberg states, and this influence is studied by measuring the n = 70 Rydberg state coherence at different distances from the cavity. Our measurements suggest that a Rydberg array may be placed ∼ 200 μm away from a nanophotonic device while retaining high quantum gate fidelities. Our methods can be applied to other atomic species and device geometries, paving the path to quantum networks of Rydberg array processors.
We demonstrate photon-mediated interactions between two individually trapped atoms coupled to a nanophotonic cavity. Specifically, we observe collective enhancement when the atoms are resonant with the cavity and level repulsion when the cavity is coupled to the atoms in the dispersive regime. Our approach makes use of individual control over the internal states of the atoms and their position with respect to the cavity mode, as well as the light shifts to tune atomic transitions individually, allowing us to directly observe the anticrossing of the bright and dark two-atom states. These observations open the door for realizing quantum networks and studying quantum many-body physics based on atom arrays coupled to nanophotonic devices.
An atomic array coupled to a one-dimensional nanophotonic waveguide allows photon-mediated dipole-dipole interactions and nonreciprocal decay channels. Such an array possesses many intriguing quantum phenomena due to its distinctive and emergent quantum correlations. In this atom-waveguide quantum system, we theoretically investigate the atomic excitation dynamics and its transport property, specifically at an interface of dissimilar atomic arrays with different interparticle distances. We find that the atomic excitation dynamics is highly dependent on the interparticle distances of dissimilar arrays and the directionality of nonreciprocal couplings. By tuning these parameters, a dominant excitation reflection can be achieved at the interface of the arrays in the single excitation case. We further study two effects on the transport property—of external drive and of single excitation delocalization over multiple atoms—where we manifest a rich interplay between multisite excitation and the relative phase in determining the transport properties. Finally, we present an intriguing trapping effect of atomic excitation by designing multiple zones of dissimilar arrays. Similar to the single excitations, multiple excitations are reflected from the array interfaces and trapped as well, although complete trapping of many excitations together is relatively challenging at long time due to a faster combined decay rate. Our results can provide insights into nonequilibrium quantum dynamics in dissimilar arrays, and they can shed light on confining and controlling quantum registers useful for quantum information processing. Published by the American Physical Society 2024
Engineering atom-atom interactions is essential both for controlling novel phases of matter and for efficient preparation of many-body entangled states, which are key resources in quantum communication, computation, and metrology. In this work, we propose a scheme to tailor these interactions by coupling driven atom pairs to optical cavity photons via a molecular state in the dispersive regime, resulting in an effective photon-field-dependent potential. As an illustrative example, by analyzing the quantum Fisher information, we show that such induced interactions can generate robust many-body entanglement in two-mode ultracold bosons in an optical cavity. By tuning the photon-induced interactions through the cavity drive, we identify conditions for preparing highly entangled states on timescales that mitigate decoherence due to photon loss. Our results show that entanglement formation rate scales strongly with both photon and atom number, dramatically reducing the timescale compared to bare atomic interactions. We also identify an optimal measurement for exploiting the metrological potential of the atomic state in an interferometric protocol with significant photon losses, saturating the quantum Cramer-Rao lower bound. Furthermore, we show that despite these losses the atomic state exhibits strong Bell correlations. Our results pave the way for engineering atom-atom interactions to study novel phases of light and matter in hybrid atom-photon systems, as well as for tailoring complex quantum states for new quantum technology protocols and fundamental tests of quantum mechanics.
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.