Stability of flat-band Bose-Einstein condensation from the geometry of compact localized states

Fuente: arXiv
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Main Author: Huhtinen, Kukka-Emilia
Format: Preprint
Published: 2026
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author Huhtinen, Kukka-Emilia
author_facet Huhtinen, Kukka-Emilia
contents We consider Bose-Einstein condensation in flat-band models from a real-space perspective. Using a basis of compact localized states, we reformulate the minimization of the mean-field energy as a Euclidian geometry problem. Within Bogoliubov theory, we show that flat-band models where the solutions to this problem are frameworks consisting of triangles with nonzero area are promising for condensation, whereas for instance square frameworks indicate condensation in a single mode is impossible. When restricting the analysis to Bloch states, this approach can be related to a necessary condition for a non-vanishing quantum distance. This work provides a new perspective on how condensation in flat bands is destabilized, and offers principles for the construction of models where flat-band Bose-Einstein condensation is possible.
format Preprint
id arxiv_https___arxiv_org_abs_2603_09954
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Stability of flat-band Bose-Einstein condensation from the geometry of compact localized states
Huhtinen, Kukka-Emilia
Quantum Gases
We consider Bose-Einstein condensation in flat-band models from a real-space perspective. Using a basis of compact localized states, we reformulate the minimization of the mean-field energy as a Euclidian geometry problem. Within Bogoliubov theory, we show that flat-band models where the solutions to this problem are frameworks consisting of triangles with nonzero area are promising for condensation, whereas for instance square frameworks indicate condensation in a single mode is impossible. When restricting the analysis to Bloch states, this approach can be related to a necessary condition for a non-vanishing quantum distance. This work provides a new perspective on how condensation in flat bands is destabilized, and offers principles for the construction of models where flat-band Bose-Einstein condensation is possible.
title Stability of flat-band Bose-Einstein condensation from the geometry of compact localized states
topic Quantum Gases
url https://arxiv.org/abs/2603.09954