arXiv subjects

I Gusti Ngurah Yudi Handayana

Publications and source records attributed to I Gusti Ngurah Yudi Handayana.

6 recordsLinked to original sources

arXiv2026

High-order quantum correlations in nonlinear waveguide quantum electrodynamics

Quantum emitters coupled to nonlinear one-dimensional waveguides provide a route for quantum-state engineering by utilizing parametric gain accumulation along with modified waveguide-mediated interactions. Since the accumulated squeezing depends on propagation distance, different emitter separations can experience different effective gain, making the spatial structure of connected quantum correlations a central feature of the dynamics. Here we investigate the transient and steady-state connected correlations of emitter arrays coupled to a parametrically driven waveguide. Using an effective master equation for nonlinear waveguide QED, we analyze second- and third-order connected correlations as functions of the squeezing parameter and interparticle distance. In the two-emitter limit, accumulated squeezing drives excitation buildup and generates a nonzero connected second-order correlation. For many-emitter arrays, tuning the interparticle distance switches the dominant local second-order correlation between the bulk and boundary regions, and enables an analogous spatial control of genuine third-order connected correlations. In the steady state, the averaged second-order correlation exhibits sign-changing and nonmonotonic behavior in the squeezing--interparticle distance parameter space, whereas the third-order connected correlation is strongly enhanced by increasing the squeezing parameter. These results identify nonlinear waveguide QED as a tunable platform for spatially controlling connected quantum correlations and provide insights into correlation engineering in open quantum optical arrays. We further show that this local contrast remains visible in both odd and even number of atomic arrays.

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arXiv2026

Fast and High Excitation Transport in Waveguide Quantum Electrodynamics

Waveguide quantum electrodynamics (wQED) with underlying collective and long-range atom-atom interactions has led to many distinct dynamical phenomena, including modified collective radiations and intriguing quantum correlations. It stands out as a unique platform to illustrate correlated photon transport, as well as to promise applications in quantum information processing. Here we manifest a fast and high atomic excitation transport by employing two separated chirally-coupled atomic arrays. This enhanced waveguide-mediated transport of excitations emerges due to the dominance of few subradiant right eigenstates that are spectrally isolated and spatially localized in the system's dynamics. Contrary to the instinct of applying the cascaded systems with unidirectional couplings to expedite direct and high excitation transport, the optimal system configurations in open wQED systems demand slight or finite nonreciprocal decay channels to facilitate energy transport by exploiting waveguide-mediated couplings. We also investigate the effect of the couplings' directionality and the scaling of atom number on the transport properties. Our results showcase the wide applicability in wQED platforms and provide insights into quantum engineering and quantum information applications.

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arXiv2026

Manipulating Excitation Dynamics in Structured Waveguide Quantum Electrodynamics

Waveguide quantum electrodynamics (wQED) has become a central platform for studying collective light-matter interactions in low-dimensional photonic environments. While conventional wQED systems rely on uniform chirality or reciprocal emitter-waveguide coupling, we propose a structured wQED framework, where the coupling directionality of each emitter can be engineered locally to control excitation transport in an atom-nanophotonic interface. For different combinations of patterned coupling directionalities of the emitters, we identify four representative configurations that exhibit distinct dynamical behaviors: centering, wave-like, leap-frog, and dispersion excitations. Spectral analysis of the effective non-Hermitian Hamiltonian reveals that these dynamics originate from interferences among subradiant eigenmodes. Variance analysis further quantifies the spreading of excitation as functions of interatomic spacing and global chirality, showing tunable localization-delocalization transitions. Including nonguided losses, we find that the transport characteristics remain robust for realistic coupling efficiencies (beta >= 0.99). These results establish structured wQED as a practical route to manipulate excitation localization, coherence, and transport through programmable directionality patterns, paving the way for controllable subradiant transport and chiral quantum information routing.

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arXiv2024

Suppression of Quantum Correlations in a Clean-Disordered Atom-Nanophotonic Interface

Quantum correlations are essential to the emergent behaviors of quantum systems, supporting key phenomena such as localization or delocalization of particles, quantum avalanches in many-body localized systems, and quantum information transfer. In open atom-nanophotonic systems characterized by long-range spin-exchange interactions, we examine the influence of clean system size on high-order quantum correlations among a clean-disordered atomic array with multiple atomic excitations. By initializing the system far from equilibrium, we observe a suppression of quantum correlations for localized atomic excitations in the disordered zone as the clean system size increases, showcasing the delocalization behavior in the high-order spin-exchange processes. The calculation of the entanglement entropy at the interface further substantiates this thermalizing effect. Our results manifest distinct quantum correlations enabled by long-range interactions mediated by the waveguide, enhance the theoretical comprehension of clean-disordered systems, and provide insights to nonequilibrium quantum dynamics in an atom-nanophotonic platform.

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arXiv2024

Atomic excitation trapping in dissimilar chirally-coupled atomic arrays

Atomic array coupled to a one-dimensional nanophotonic waveguide allows photon-mediated dipole-dipole interactions and nonreciprocal decay channels, which hosts many intriguing quantum phenomena owing 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 hugely depends 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 multi-site 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 to nonequilibrium quantum dynamics in dissimilar arrays and shed light on confining and controlling quantum registers useful for quantum information processing.

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arXiv2023

Steady-state phases and interaction-induced depletion in a driven-dissipative chirally-coupled dissimilar atomic array

A nanophotonic waveguide coupled with an atomic array forms one of the strongly-coupled quantum interfaces to showcase many fascinating collective features of quantum dynamics. In particular for a dissimilar array of two different interparticle spacings with competing photon-mediated dipole-dipole interactions and directionality of couplings, we study the steady-state phases of atomic excitations under a weakly-driven condition of laser field. We identify a partial set of steady-state phases of the driven system composed of combinations of steady-state solutions in a homogeneous array. We also reveal an intricate role of the atom at the interface of the dissimilar array in determining the steady-state phases and find an alteration in the dichotomy of the phases strongly associated with steady-state distributions with crystalline orders. We further investigate in detail the interaction-induced depletion in half of the dissimilar array. This blockaded region results from two contrasting interparticle spacings near the reciprocal coupling regime, which is evidenced from the analytical solutions under the reciprocal coupling. Our results can provide insights in the driven-dissipative quantum phases of atomic excitations with nonreciprocal couplings and pave the avenues toward quantum simulations of exotic many-body states essential for quantum information applications.

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