Caustic formation in expanding condensates of cold atoms
We study the evolution of density in an expanding Bose-Einstein condensate that initially has a spatially varying phase, concentrating on behaviour when these phase variations are large. In this regime large density fluctuations develop during expansion. Maxima have a characteristic density that div...
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| Format: | Journal article |
| Language: | English |
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2009
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| _version_ | 1797096328775335936 |
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| author | Chalker, J Shapiro, B |
| author_facet | Chalker, J Shapiro, B |
| author_sort | Chalker, J |
| collection | OXFORD |
| description | We study the evolution of density in an expanding Bose-Einstein condensate that initially has a spatially varying phase, concentrating on behaviour when these phase variations are large. In this regime large density fluctuations develop during expansion. Maxima have a characteristic density that diverges with the amplitude of phase variations and their formation is analogous to that of caustics in geometrical optics. We analyse in detail caustic formation in a quasi-one dimensional condensate, which before expansion is subject to a periodic or random optical potential, and we discuss the equivalent problem for a quasi-two dimensional system. We also examine the influence of many-body correlations in the initial state on caustic formation for a Bose gas expanding from a strictly one-dimensional trap. In addition, we study a similar arrangement for non-interacting fermions, showing that Fermi surface discontinuities in the momentum distribution give rise in that case to sharp peaks in the spatial derivative of the density. We discuss recent experiments and argue that fringes reported in time of flight images by Chen and co-workers [Phys. Rev. A 77, 033632 (2008)] are an example of caustic formation. |
| first_indexed | 2024-03-07T04:40:18Z |
| format | Journal article |
| id | oxford-uuid:d1648af3-1a6e-47bb-aac0-88989058d3ee |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T04:40:18Z |
| publishDate | 2009 |
| record_format | dspace |
| spelling | oxford-uuid:d1648af3-1a6e-47bb-aac0-88989058d3ee2022-03-27T07:56:40ZCaustic formation in expanding condensates of cold atomsJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:d1648af3-1a6e-47bb-aac0-88989058d3eeEnglishSymplectic Elements at Oxford2009Chalker, JShapiro, BWe study the evolution of density in an expanding Bose-Einstein condensate that initially has a spatially varying phase, concentrating on behaviour when these phase variations are large. In this regime large density fluctuations develop during expansion. Maxima have a characteristic density that diverges with the amplitude of phase variations and their formation is analogous to that of caustics in geometrical optics. We analyse in detail caustic formation in a quasi-one dimensional condensate, which before expansion is subject to a periodic or random optical potential, and we discuss the equivalent problem for a quasi-two dimensional system. We also examine the influence of many-body correlations in the initial state on caustic formation for a Bose gas expanding from a strictly one-dimensional trap. In addition, we study a similar arrangement for non-interacting fermions, showing that Fermi surface discontinuities in the momentum distribution give rise in that case to sharp peaks in the spatial derivative of the density. We discuss recent experiments and argue that fringes reported in time of flight images by Chen and co-workers [Phys. Rev. A 77, 033632 (2008)] are an example of caustic formation. |
| spellingShingle | Chalker, J Shapiro, B Caustic formation in expanding condensates of cold atoms |
| title | Caustic formation in expanding condensates of cold atoms |
| title_full | Caustic formation in expanding condensates of cold atoms |
| title_fullStr | Caustic formation in expanding condensates of cold atoms |
| title_full_unstemmed | Caustic formation in expanding condensates of cold atoms |
| title_short | Caustic formation in expanding condensates of cold atoms |
| title_sort | caustic formation in expanding condensates of cold atoms |
| work_keys_str_mv | AT chalkerj causticformationinexpandingcondensatesofcoldatoms AT shapirob causticformationinexpandingcondensatesofcoldatoms |