Saved in:
| Main Authors: | , , , , |
|---|---|
| Format: | Preprint |
| Published: |
2026
|
| Subjects: | |
| Online Access: | https://arxiv.org/abs/2604.05258 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866910107404599296 |
|---|---|
| author | Kim, Yeongjun Utesov, Oleg I. Andreanov, Alexei Fistul, Mikhail V. Flach, Sergej |
| author_facet | Kim, Yeongjun Utesov, Oleg I. Andreanov, Alexei Fistul, Mikhail V. Flach, Sergej |
| contents | We investigate the ground-state properties of one-dimensional Gross-Pitaevskii flat-band lattices. We uncover a geometry-driven phase transition into a macroscopically degenerate nematic state with broken time reversal symmetry. Focusing on all-bands-flat (ABF) models, we demonstrate that even infinitesimal onsite interactions can destabilize a uniform, constant-phase condensate, driving the system into a nematic manifold as the flat-band geometry controlled parameter $θ\geq π/8$. At a critical endpoint (\(θ=π/4\)), where the compact localized states exhibit constant amplitudes, we identify an additional pair of density-modulated ground states characterized by vanishing phase stiffness. Utilizing Bogoliubov-de Gennes excitations and simulated annealing, we show that these density-modulated phases are thermally selected at low temperatures via an order-by-disorder mechanism. Finally, we demonstrate that these non-trivial condensate phases extend beyond ABF models, as exemplified by the sawtooth lattice. Our findings also reveal that the sound velocity in flat-band condensates is a sensitive probe of the underlying geometric phase structure. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2604_05258 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Nematic Phase Transitions and Density Modulations in 1D Flat Band Condensates Kim, Yeongjun Utesov, Oleg I. Andreanov, Alexei Fistul, Mikhail V. Flach, Sergej Statistical Mechanics We investigate the ground-state properties of one-dimensional Gross-Pitaevskii flat-band lattices. We uncover a geometry-driven phase transition into a macroscopically degenerate nematic state with broken time reversal symmetry. Focusing on all-bands-flat (ABF) models, we demonstrate that even infinitesimal onsite interactions can destabilize a uniform, constant-phase condensate, driving the system into a nematic manifold as the flat-band geometry controlled parameter $θ\geq π/8$. At a critical endpoint (\(θ=π/4\)), where the compact localized states exhibit constant amplitudes, we identify an additional pair of density-modulated ground states characterized by vanishing phase stiffness. Utilizing Bogoliubov-de Gennes excitations and simulated annealing, we show that these density-modulated phases are thermally selected at low temperatures via an order-by-disorder mechanism. Finally, we demonstrate that these non-trivial condensate phases extend beyond ABF models, as exemplified by the sawtooth lattice. Our findings also reveal that the sound velocity in flat-band condensates is a sensitive probe of the underlying geometric phase structure. |
| title | Nematic Phase Transitions and Density Modulations in 1D Flat Band Condensates |
| topic | Statistical Mechanics |
| url | https://arxiv.org/abs/2604.05258 |