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Main Authors: Liang, Guo-Hua, Mei, Ai-Guo, Lai, Men-Yun, Xu, Shu-Sheng
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2509.00432
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author Liang, Guo-Hua
Mei, Ai-Guo
Lai, Men-Yun
Xu, Shu-Sheng
author_facet Liang, Guo-Hua
Mei, Ai-Guo
Lai, Men-Yun
Xu, Shu-Sheng
contents We study the quantum dynamics of a particle confined in a twisted tube with a linearly varying cross section. By relating a general linear transformation matrix to the system's Hamiltonian, we use an extended thin-layer method to derive an effective Hamiltonian for tangential motion under mild and general linear transformations. Explicit forms are provided for three fundamental transformations: rotation, scaling, and shearing. Rotation introduces a gauge field coupled to angular momentum, while scaling and shearing produce geometric potentials that lift degeneracies in non-circular cross sections. In square cross sections, these transformations cause energy splittings among formerly degenerate states, whereas circular cross sections retain degeneracy. Through an example combining rotation and squeezing, we analyze state evolution and compute the quantum geometric tensor to quantify geometric response. Our results demonstrate how geometric transformations can tailor quantum states and suggest that circular waveguides are more robust against mode mixing.
format Preprint
id arxiv_https___arxiv_org_abs_2509_00432
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Quantum States in Twisted Tubes with Linear Cross-Section Variation
Liang, Guo-Hua
Mei, Ai-Guo
Lai, Men-Yun
Xu, Shu-Sheng
Quantum Physics
Mesoscale and Nanoscale Physics
We study the quantum dynamics of a particle confined in a twisted tube with a linearly varying cross section. By relating a general linear transformation matrix to the system's Hamiltonian, we use an extended thin-layer method to derive an effective Hamiltonian for tangential motion under mild and general linear transformations. Explicit forms are provided for three fundamental transformations: rotation, scaling, and shearing. Rotation introduces a gauge field coupled to angular momentum, while scaling and shearing produce geometric potentials that lift degeneracies in non-circular cross sections. In square cross sections, these transformations cause energy splittings among formerly degenerate states, whereas circular cross sections retain degeneracy. Through an example combining rotation and squeezing, we analyze state evolution and compute the quantum geometric tensor to quantify geometric response. Our results demonstrate how geometric transformations can tailor quantum states and suggest that circular waveguides are more robust against mode mixing.
title Quantum States in Twisted Tubes with Linear Cross-Section Variation
topic Quantum Physics
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2509.00432