Anomalous tunneling as a low-energy theorem for Nambu-Goldstone modes

Fuente: arXiv
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Autori principali: Fujii, Keisuke, Kagamihara, Daichi, Hongo, Masaru
Natura: Preprint
Pubblicazione: 2026
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author Fujii, Keisuke
Kagamihara, Daichi
Hongo, Masaru
author_facet Fujii, Keisuke
Kagamihara, Daichi
Hongo, Masaru
contents Anomalous tunneling refers to the phenomenon in which the transmission coefficient through a potential barrier approaches unity as the energy of an incident particle or quasiparticle tends to zero. This counterintuitive effect has been reported in systems exhibiting spontaneous symmetry breaking (SSB), such as superfluids, yet the general conditions for its occurrence remain unclear. In this Letter, we establish that anomalous tunneling of Nambu-Goldstone (NG) modes is a universal low-energy theorem dictated solely by symmetry and scaling, using a low-energy effective field theory (EFT) framework. We formulate the scattering of NG modes by external potentials in terms of spatially dependent EFT coefficients and demonstrate that symmetry-preserving localized potentials are irrelevant in the long-wavelength limit, leading to perfect transmission. In contrast, symmetry-breaking perturbations are relevant and suppress transmission, resulting in the absence of anomalous tunneling. We illustrate this universal behavior with explicit examples of superfluid phonons and magnons.
format Preprint
id arxiv_https___arxiv_org_abs_2604_27489
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Anomalous tunneling as a low-energy theorem for Nambu-Goldstone modes
Fujii, Keisuke
Kagamihara, Daichi
Hongo, Masaru
Quantum Gases
High Energy Physics - Theory
Anomalous tunneling refers to the phenomenon in which the transmission coefficient through a potential barrier approaches unity as the energy of an incident particle or quasiparticle tends to zero. This counterintuitive effect has been reported in systems exhibiting spontaneous symmetry breaking (SSB), such as superfluids, yet the general conditions for its occurrence remain unclear. In this Letter, we establish that anomalous tunneling of Nambu-Goldstone (NG) modes is a universal low-energy theorem dictated solely by symmetry and scaling, using a low-energy effective field theory (EFT) framework. We formulate the scattering of NG modes by external potentials in terms of spatially dependent EFT coefficients and demonstrate that symmetry-preserving localized potentials are irrelevant in the long-wavelength limit, leading to perfect transmission. In contrast, symmetry-breaking perturbations are relevant and suppress transmission, resulting in the absence of anomalous tunneling. We illustrate this universal behavior with explicit examples of superfluid phonons and magnons.
title Anomalous tunneling as a low-energy theorem for Nambu-Goldstone modes
topic Quantum Gases
High Energy Physics - Theory
url https://arxiv.org/abs/2604.27489