Fragmented condensation in Bose–Hubbard trimers with tunable tunnelling
We consider a Bose–Hubbard (BH) trimer, i.e. an ultracold Bose gas populating three quantum states. The latter can be either different sites of a triple-well potential or three internal states of the atoms. The bosons can tunnel between different states with variable tunnelling strength between two...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2015-01-01
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| Series: | New Journal of Physics |
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| Online Access: | https://doi.org/10.1088/1367-2630/17/7/073014 |
| _version_ | 1797751170177957888 |
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| author | A Gallemí M Guilleumas J Martorell R Mayol A Polls B Juliá-Díaz |
| author_facet | A Gallemí M Guilleumas J Martorell R Mayol A Polls B Juliá-Díaz |
| author_sort | A Gallemí |
| collection | DOAJ |
| description | We consider a Bose–Hubbard (BH) trimer, i.e. an ultracold Bose gas populating three quantum states. The latter can be either different sites of a triple-well potential or three internal states of the atoms. The bosons can tunnel between different states with variable tunnelling strength between two of them. This will allow us to study; (i) different geometrical configurations, i.e. from a closed triangle to three aligned wells and (ii) a triangular configuration with a π -phase, i.e. by setting one of the tunnellings negative. By solving the corresponding three-site BH Hamiltonian we obtain the ground state of the system as a function of the trap topology. We characterize the different ground states by means of the coherence and entanglement properties. For small repulsive interactions, fragmented condensates are found for the π -phase case. These are found to be robust against small variations of the tunnelling in the small interaction regime. A low-energy effective many-body Hamiltonian restricted to the degenerate manifold provides a compelling description of the π -phase degeneration and explains the low-energy spectrum as excitations of discrete semifluxon states. |
| first_indexed | 2024-03-12T16:44:35Z |
| format | Article |
| id | doaj.art-7dc16d48d90a4bcfb27b2176ba2d0090 |
| institution | Directory Open Access Journal |
| issn | 1367-2630 |
| language | English |
| last_indexed | 2024-03-12T16:44:35Z |
| publishDate | 2015-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | New Journal of Physics |
| spelling | doaj.art-7dc16d48d90a4bcfb27b2176ba2d00902023-08-08T14:18:58ZengIOP PublishingNew Journal of Physics1367-26302015-01-0117707301410.1088/1367-2630/17/7/073014Fragmented condensation in Bose–Hubbard trimers with tunable tunnellingA Gallemí0M Guilleumas1J Martorell2R Mayol3A Polls4B Juliá-Díaz5Departament d’Estructura i Constituents de la Matèria, Facultat de Física, Universitat de Barcelona , E-08028 Barcelona, Spain; Institut de Nanociència i Nanotecnologia de la Universitat de Barcelona (INUB), E-08028 Barcelona, SpainDepartament d’Estructura i Constituents de la Matèria, Facultat de Física, Universitat de Barcelona , E-08028 Barcelona, Spain; Institut de Nanociència i Nanotecnologia de la Universitat de Barcelona (INUB), E-08028 Barcelona, SpainDepartament d’Estructura i Constituents de la Matèria, Facultat de Física, Universitat de Barcelona , E-08028 Barcelona, SpainDepartament d’Estructura i Constituents de la Matèria, Facultat de Física, Universitat de Barcelona , E-08028 Barcelona, Spain; Institut de Nanociència i Nanotecnologia de la Universitat de Barcelona (INUB), E-08028 Barcelona, SpainDepartament d’Estructura i Constituents de la Matèria, Facultat de Física, Universitat de Barcelona , E-08028 Barcelona, Spain; Institut de Ciències del Cosmos, Universitat de Barcelona , ICC-UB, Martí i Franquès 1, E-08028 Barcelona, SpainDepartament d’Estructura i Constituents de la Matèria, Facultat de Física, Universitat de Barcelona , E-08028 Barcelona, Spain; Institut de Ciències del Cosmos, Universitat de Barcelona , ICC-UB, Martí i Franquès 1, E-08028 Barcelona, Spain; ICFO-Institut de Ciències Fotòniques, Parc Mediterrani de la Tecnologia, E-08860 Barcelona, SpainWe consider a Bose–Hubbard (BH) trimer, i.e. an ultracold Bose gas populating three quantum states. The latter can be either different sites of a triple-well potential or three internal states of the atoms. The bosons can tunnel between different states with variable tunnelling strength between two of them. This will allow us to study; (i) different geometrical configurations, i.e. from a closed triangle to three aligned wells and (ii) a triangular configuration with a π -phase, i.e. by setting one of the tunnellings negative. By solving the corresponding three-site BH Hamiltonian we obtain the ground state of the system as a function of the trap topology. We characterize the different ground states by means of the coherence and entanglement properties. For small repulsive interactions, fragmented condensates are found for the π -phase case. These are found to be robust against small variations of the tunnelling in the small interaction regime. A low-energy effective many-body Hamiltonian restricted to the degenerate manifold provides a compelling description of the π -phase degeneration and explains the low-energy spectrum as excitations of discrete semifluxon states.https://doi.org/10.1088/1367-2630/17/7/073014Bose–Hubbard trimersmany-body fragmentationsemifluxons |
| spellingShingle | A Gallemí M Guilleumas J Martorell R Mayol A Polls B Juliá-Díaz Fragmented condensation in Bose–Hubbard trimers with tunable tunnelling New Journal of Physics Bose–Hubbard trimers many-body fragmentation semifluxons |
| title | Fragmented condensation in Bose–Hubbard trimers with tunable tunnelling |
| title_full | Fragmented condensation in Bose–Hubbard trimers with tunable tunnelling |
| title_fullStr | Fragmented condensation in Bose–Hubbard trimers with tunable tunnelling |
| title_full_unstemmed | Fragmented condensation in Bose–Hubbard trimers with tunable tunnelling |
| title_short | Fragmented condensation in Bose–Hubbard trimers with tunable tunnelling |
| title_sort | fragmented condensation in bose hubbard trimers with tunable tunnelling |
| topic | Bose–Hubbard trimers many-body fragmentation semifluxons |
| url | https://doi.org/10.1088/1367-2630/17/7/073014 |
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