Ferroelectricity in magnon Bose-Einstein condensate: non-reciprocal superfluidity, exceptional points and Majorana bosons

Fuente: arXiv
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Main Authors: Yamamoto, Kazuki, Kawakami, Takuto, Koshino, Mikito
Format: Preprint
Published: 2025
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author Yamamoto, Kazuki
Kawakami, Takuto
Koshino, Mikito
author_facet Yamamoto, Kazuki
Kawakami, Takuto
Koshino, Mikito
contents We investigate a ferroelectric instability of a magnon Bose-Einstein condensate, mediated by its interaction with an electric field through a geometric Aharonov-Casher (AC) phase. A distinct feature of the system is the positive feedback loop in which an electric field induces magnon orbital motion via the AC phase, generating electric polarization that in turn enhances the original field. Based on bosonic Bogoliubov-de Gennes (BdG) mean-field theory, we show that this feedback drives a spontaneous ferroelectric transition in the magnon superfluid, accompanied by a persistent magnon supercurrent. In the resulting ferroelectric phase, the quasiparticle excitation spectrum becomes nonreciprocal, reflecting spontaneous breaking of spatial inversion symmetry. At the critical point of the transition, the bosonic BdG Hamiltonian exhibits coalescence of both eigenvalues and eigenvectors, forming an exceptional point. The corresponding eigenvector is an equally weighted superposition of bosonic quasiparticle and quasihole states and is invariant under particle-hole transformation, allowing it to be interpreted as a bosonic analog of a Majorana fermion.
format Preprint
id arxiv_https___arxiv_org_abs_2512_22073
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Ferroelectricity in magnon Bose-Einstein condensate: non-reciprocal superfluidity, exceptional points and Majorana bosons
Yamamoto, Kazuki
Kawakami, Takuto
Koshino, Mikito
Mesoscale and Nanoscale Physics
Quantum Gases
Superconductivity
We investigate a ferroelectric instability of a magnon Bose-Einstein condensate, mediated by its interaction with an electric field through a geometric Aharonov-Casher (AC) phase. A distinct feature of the system is the positive feedback loop in which an electric field induces magnon orbital motion via the AC phase, generating electric polarization that in turn enhances the original field. Based on bosonic Bogoliubov-de Gennes (BdG) mean-field theory, we show that this feedback drives a spontaneous ferroelectric transition in the magnon superfluid, accompanied by a persistent magnon supercurrent. In the resulting ferroelectric phase, the quasiparticle excitation spectrum becomes nonreciprocal, reflecting spontaneous breaking of spatial inversion symmetry. At the critical point of the transition, the bosonic BdG Hamiltonian exhibits coalescence of both eigenvalues and eigenvectors, forming an exceptional point. The corresponding eigenvector is an equally weighted superposition of bosonic quasiparticle and quasihole states and is invariant under particle-hole transformation, allowing it to be interpreted as a bosonic analog of a Majorana fermion.
title Ferroelectricity in magnon Bose-Einstein condensate: non-reciprocal superfluidity, exceptional points and Majorana bosons
topic Mesoscale and Nanoscale Physics
Quantum Gases
Superconductivity
url https://arxiv.org/abs/2512.22073