arXiv subjects

Deyi Kong

Publications and source records attributed to Deyi Kong.

4 recordsLinked to original sources

arXiv2026

High-purity fluorescence photon bundle emission from two separate emitters

We propose a scheme for generating high-purity fluorescence two-photon bundles from two spatially separate two-level emitters, whose correlated excitation is mediated by a strongly driven auxiliary emitter. Unlike bosonic-mode-based approaches, the finite excitation space of the two target emitters intrinsically excludes higher-excitation manifolds, and thus eliminates impurity photons associated with undesired higher-excitation states. We further analytically characterize the residual population of off-resonant single-excitation states and show that suppressing the corresponding leakage improves photon bundle purity. Our scheme offers a feasible pathway for constructing high-purity quantum light sources with promising applications in quantum information processing.

quant-ph↗

arXiv2026

Enhanced two-photon sources in a cavity-coupled two-atom system

We propose a component-selective scheme for improving two-photon sources in a cavity-coupled two-atom system, where a single cavity mode interacts with two two-level atoms driven by phase-controlled classical fields of the same frequency. By controlling the atomic detunings and driving phase, the system can be tailored toward optimized cavity-field two-photon blockade or strongly correlated fluorescence photon-pair emission. When the two-cavity-photon component is enhanced, the cavity field exhibits optimized two-photon blockade with simultaneous suppression of unwanted one- and three-photon components at a comparable two-photon population. In another parameter regime, strongly correlated fluorescence photon pairs can also be generated from the two atoms by selecting the double-atomic-excitation component in the same two-excitation manifold. This approach provides a route toward high-quality and versatile two-photon sources, with potential applications in few-photon quantum optics and quantum information processing.

quant-ph↗

arXiv2026

Chiral interaction enhanced magnon bundle emission

In this paper, we suggest a chiral interaction scheme to enhance magnon bundle emission by placing a qubit and a magnon into a cascaded-cavity setup, respectively. It is found that the unidirectional interaction prolongs the lifetime of the target excited state, thereby suppressing the magnon re-excitation and promoting both the average purity and number of two-magnon bundles. Consequently, the chiral interaction not only offers directional control but also improves the quality of the multi-magnon source, which may find potential applications in quantum information processing.

quant-ph↗

arXiv2026

Natural Hypergradient Descent: Algorithm Design, Convergence Analysis, and Parallel Implementation

In this work, we propose Natural Hypergradient Descent (NHGD), a new method for solving bilevel optimization problems. To address the computational bottleneck in hypergradient estimation--namely, the need to compute or approximate Hessian inverse--we exploit the statistical structure of the inner optimization problem and use the empirical Fisher information matrix as an asymptotically consistent surrogate for the Hessian. This design enables a parallel optimize-and-approximate framework in which the Hessian-inverse approximation is updated synchronously with the stochastic inner optimization, reusing gradient information at negligible additional cost. Our main theoretical contribution establishes high-probability error bounds and sample complexity guarantees for NHGD that match those of state-of-the-art optimize-then-approximate methods, while significantly reducing computational time overhead. Empirical evaluations on representative bilevel learning tasks further demonstrate the practical advantages of NHGD, highlighting its scalability and effectiveness in large-scale machine learning settings.

cs.LG↗