Bound-like State in a 1D Self-Similar Delta-Barrier Array

Fuente: arXiv
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Autores principales: Tang, Jia-Chen, Hou, Xu-Yang, He, Yan, Guo, Hao
Formato: Preprint
Publicado: 2025
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author Tang, Jia-Chen
Hou, Xu-Yang
He, Yan
Guo, Hao
author_facet Tang, Jia-Chen
Hou, Xu-Yang
He, Yan
Guo, Hao
contents We investigate a one-dimensional quantum system with a self-similar arrangement of delta-function potential barriers, exhibiting discrete scale invariance. The singular potential induces kinematically enforced symmetry breaking at $x=0$, decoupling the positive and negative spatial regions and leading to non-symmetric zero-energy states. We demonstrate that the system supports a unique zero-energy wavefunction, which, though not square-integrable, decays to zero at infinity and acts as a bound-like state with self-similar properties under discrete scaling transformations, akin to Efimov physics but limited to a single state. In momentum space, this wavefunction exhibits a threshold singularity at low momenta, with behavior depending on the scaling exponent $α$:power-law divergence and log-periodic modulations for $0 < α< 1$, logarithmic divergence for $α= 1$, and a finite limit for $α> 1$, which may be observable through time-of-flight or spectroscopic measurements in cold atom experiments. The system's continuous spectrum, starting at zero energy, lacks discrete bound states. These findings highlight the role of singular potentials in generating scale-invariant quantum phenomena and provide a minimal framework for studying discrete scale symmetry and its potential experimental signatures.
format Preprint
id arxiv_https___arxiv_org_abs_2505_01317
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Bound-like State in a 1D Self-Similar Delta-Barrier Array
Tang, Jia-Chen
Hou, Xu-Yang
He, Yan
Guo, Hao
Quantum Physics
We investigate a one-dimensional quantum system with a self-similar arrangement of delta-function potential barriers, exhibiting discrete scale invariance. The singular potential induces kinematically enforced symmetry breaking at $x=0$, decoupling the positive and negative spatial regions and leading to non-symmetric zero-energy states. We demonstrate that the system supports a unique zero-energy wavefunction, which, though not square-integrable, decays to zero at infinity and acts as a bound-like state with self-similar properties under discrete scaling transformations, akin to Efimov physics but limited to a single state. In momentum space, this wavefunction exhibits a threshold singularity at low momenta, with behavior depending on the scaling exponent $α$:power-law divergence and log-periodic modulations for $0 < α< 1$, logarithmic divergence for $α= 1$, and a finite limit for $α> 1$, which may be observable through time-of-flight or spectroscopic measurements in cold atom experiments. The system's continuous spectrum, starting at zero energy, lacks discrete bound states. These findings highlight the role of singular potentials in generating scale-invariant quantum phenomena and provide a minimal framework for studying discrete scale symmetry and its potential experimental signatures.
title Bound-like State in a 1D Self-Similar Delta-Barrier Array
topic Quantum Physics
url https://arxiv.org/abs/2505.01317