Wen-Jie Qiu | Searcharxiv

arXiv2026

Quantum scattering by intersecting δ-potential barriers: from Gaudin's kaleidoscope to quantum Galperin billiards

We develop a general framework for the scattering of a plane wave by a class of Gaudin kaleidoscope models: straight $δ$-potential barriers intersecting at a common point. The projected Lippmann-Schwinger equations split into a singular part, a finite pole closure generated by a geometric moving rule, and a regular remainder, the outgoing state being an atomic measure on the circle. At the special angles $π/N$, where the intersecting barriers generate the dihedral group $D_N$, the number of channels stays fixed, whereas at generic angles channels are created and destroyed, opening smoothly from zero weight as a critical direction is crossed. This leaves no singular trace in the probabilities, being carried instead by the phase shifts, a quantum-classical correspondence beyond the reach of the coordinate Bethe ansatz. The same equations solve the quantum Galperin billiards exactly, the method of images reducing them to a single linear system whose phase shifts follow in closed form.

quant-ph↗

arXiv2026

Kaleidoscope Yang-Baxter Equation for Gaudin's Kaleidoscope models

Recently, researchers have proposed the Asymmetric Bethe ansatz method - a theoretical tool that extends the scope of Bethe ansatz-solvable models by "breaking" partial mirror symmetry via the introduction of a fully reflecting boundary. Within this framework, the integrability conditions which were originally put forward by Gaudin have been further generalized. In this work, building on Gaudin's generalized kaleidoscope model, we present a detailed investigation of the relationship between DN symmetry and its integrability. We demonstrate that the mathematical essence of integrability in this class of models is characterized by a newly proposed Kaleidoscope Yang-Baxter Equation. Furthermore, we show that the solvability of a model via the coordinate Bethe ansatz depends not only on the consistency relations satisfied by scattering matrices, but also on the model's boundary conditions and the symmetry of the subspace where solutions are sought. Through finite element method based numerical studies, we further confirm that Bethe ansatz integrability arises in a specific symmetry sector. Finally, by analyzing the algebraic structure of the Kaleidoscope Yang-Baxter Equation, we derive a series of novel quantum algebraic identities within the framework of quantum torus algebra.

nlin.SI↗