
Summary
The paper studies the quantum lattice transport along an infinitely extended perturbation, analyzing the band spectrum of a periodic quantum graph with a δ-coupling of strength γ in the vertices perturbed by changing the latter at an infinite straight array of vertices to a γ ̸= γ.
Highlights
- The authors consider a periodic quantum graph in the form of a rectangular lattice with a δ-coupling of strength γ in the vertices.
- The perturbation is introduced by changing the coupling strength to γ ̸= γ at an infinite straight array of vertices.
- The spectrum of the unperturbed system is analyzed using the Floquet-Bloch theory.
- The authors prove that the spectrum remains preserved as a set provided γ ̸= γ > 0.
- For all other combinations, additional bands appear in some or all gaps of the unperturbed system.
- The probability of existence of a state exponentially localized in the vicinity of the perturbation equals 1.
- The high-energy behavior of the spectrum is also analyzed.
Key Insights
- The authors use the Floquet-Bloch theory to analyze the spectrum of the unperturbed system, which is a powerful tool for studying periodic systems.
- The introduction of the perturbation leads to the appearance of new spectral bands, which can be analyzed using the band conditions derived in the paper.
- The authors prove that the spectrum remains preserved as a set provided γ ̸= γ > 0, which is an interesting result that sheds light on the behavior of the system under perturbation.
- The high-energy behavior of the spectrum is also analyzed, and the authors show that the probability of existence of a state exponentially localized in the vicinity of the perturbation equals 1.
- The paper provides a detailed analysis of the band-gap structure of the spectrum, which is an important aspect of quantum systems.
- The authors use a combination of analytical and numerical methods to study the system, which provides a comprehensive understanding of the behavior of the system.
- The results of the paper have implications for the study of quantum transport in periodic systems, which is an active area of research in condensed matter physics.
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Citation
Baradaran, M., Exner, P., & Khrabustovskyi, A. (2024). Quantum lattice transport along an infinitely extended perturbation (Version 1). arXiv. https://doi.org/10.48550/ARXIV.2412.20919