arXiv subjects

Bishuang Chen

Publications and source records attributed to Bishuang Chen.

3 recordsLinked to original sources

arXiv2026

Coherent Perfect Tunneling at Exceptional Points via Directional Degeneracy

Coherent perfect tunneling in the presence of loss and asymmetry remains a fundamental challenge in wave transport, a universal problem across optics, acoustics, and quantum mechanics. Here we demonstrate coherent perfect tunneling at an exceptional point in a passive one-dimensional waveguide cascade with three coupled interfaces. Using a waveguide-invariant scattering framework, we show that the suppression of a selected output channel originates from a directional scattering degeneracy rather than from resonance or absorption collapse. This exceptional-point condition emerges when interference between boundary-induced feedback loops promotes a simple zero of the scattering response to a second-order degeneracy. As a direct consequence, fixed coherent excitation produces a robust quartic leakage law within a transparency-dominated tunneling window. These results establish directional degeneracy as a general mechanism for loss-tolerant tunneling enabled by exceptional points across a broad class of wave systems.

physics.optics↗

arXiv2026

A waveguide kinetics framework for electrochemical polarization

Hydrogen electrocatalysis (HER/HOR) exhibits an anomalous, non-Nernstian pH dependence that has motivated competing mechanistic narratives yet still lacks a unified, transferable, and quantitatively predictive description across conditions. Here, we introduce a theory-neutral waveguide kinetics framework that reinterprets the polarization curve as a power-flow-like response, enabling a compact modal representation of interfacial kinetics. Without presuming any specific mechanism, the model quantitatively fits four representative polarization datasets historically explained by divergent theories. From each fit, we extract interpretable diagnostics, including a reflection amplitude and a useful-output density, that provide transferable metrics for interfacial efficiency. The framework thus establishes a computational experiment platform for mechanistic triangulation, operating-regime diagnosis, and the rational design of hydrogen electrocatalysts across the pH spectrum.

hep-ex↗

arXiv2026

A universal waveguide mass--energy relation for lossy one-dimensional waves in nature

Finite, lossy waveguides are ubiquitous: distributed attenuation with partial reflections produces feedback, resonance, delays and decay across electromagnetic, acoustic, photonic, quantum-transport and electrochemical interfaces. Yet standard impedance/scattering tools and weak-loss resonator approximations do not provide low-dimensional invariants that remain predictive under intrinsic asymmetry and realistic boundaries, nor do they cleanly separate total absorption from useful power delivered to a load. Here we develop a unified mass--energy framework for linear, single-mode, one-dimensional systems, in which energy-like and power-flow variables $(\mathcal{U},\mathcal{S})$ satisfy the universal invariant $\mathcal{U}^2-\mathcal{S}^2=|\Gamma_g|^2$, with the effective standing-wave ``mass'' $|\Gamma_g|$ becoming state-dependent under asymmetry. The Cai--Smith chart gives a bounded state-space map of stability, feedback proximity and operating states, and makes explicit the divergence between maximum absorption and useful delivery under loss. We derive four laws governing absorption and emission, validate the invariant in multiport optics via coherent perfect absorption at exceptional points using a basis-independent SVD criterion (reconciling quadratic vs quartic near-zero scaling), and map electrochemical polarization onto the same geometry by extracting $|\Gamma_g|$ from two-mode orthogonal fits to reveal a universal storage-to-transfer transition across pH. This framework provides a transferable design language for dissipative, boundary-controlled systems.

physics.optics↗