Collective excitations and supersolid behavior of bosonic atoms inside two crossed optical cavities
We discuss the nature of symmetry breaking and the associated collective excitations for a system of bosons coupled to the electromagnetic field of two optical cavities. For the specific configuration realized in a recent experiment at ETH [ 1 , 2 ], we show that, in absence of direct intercavity sc...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2017-01-01
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| Series: | New Journal of Physics |
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| Online Access: | https://doi.org/10.1088/1367-2630/aa9b4a |
| _version_ | 1797750662834946048 |
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| author | J Lang F Piazza W Zwerger |
| author_facet | J Lang F Piazza W Zwerger |
| author_sort | J Lang |
| collection | DOAJ |
| description | We discuss the nature of symmetry breaking and the associated collective excitations for a system of bosons coupled to the electromagnetic field of two optical cavities. For the specific configuration realized in a recent experiment at ETH [ 1 , 2 ], we show that, in absence of direct intercavity scattering and for parameters chosen such that the atoms couple symmetrically to both cavities, the system possesses an approximate U (1) symmetry which holds asymptotically for vanishing cavity field intensity. It corresponds to the invariance with respect to redistributing the total intensity $I={I}_{1}+{I}_{2}$ between the two cavities. The spontaneous breaking of this symmetry gives rise to a broken continuous translation-invariance for the atoms, creating a supersolid-like order in the presence of a Bose–Einstein condensate. In particular, we show that atom-mediated scattering between the two cavities, which favors the state with equal light intensities ${I}_{1}={I}_{2}$ and reduces the symmetry to ${{\bf{Z}}}_{2}\otimes {{\bf{Z}}}_{2}$ , gives rise to a finite value $\sim \sqrt{I}$ of the effective Goldstone mass. For strong atom driving, this low energy mode is clearly separated from an effective Higgs excitation associated with changes of the total intensity I . In addition, we compute the spectral distribution of the cavity light field and show that both the Higgs and Goldstone mode acquire a finite lifetime due to Landau damping at non-zero temperature. |
| first_indexed | 2024-03-12T16:37:05Z |
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| id | doaj.art-07a633d2a1ed4397a480fb6443c4e67f |
| institution | Directory Open Access Journal |
| issn | 1367-2630 |
| language | English |
| last_indexed | 2024-03-12T16:37:05Z |
| publishDate | 2017-01-01 |
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| series | New Journal of Physics |
| spelling | doaj.art-07a633d2a1ed4397a480fb6443c4e67f2023-08-08T14:50:03ZengIOP PublishingNew Journal of Physics1367-26302017-01-01191212302710.1088/1367-2630/aa9b4aCollective excitations and supersolid behavior of bosonic atoms inside two crossed optical cavitiesJ Lang0F Piazza1W Zwerger2Physik Department, Technische Universität München , D-85747 Garching, GermanyMax-Planck Institute for the Physics of Complex Systems, Nöthnitzer Straße 38, D-01187 Dresden, GermanyPhysik Department, Technische Universität München , D-85747 Garching, GermanyWe discuss the nature of symmetry breaking and the associated collective excitations for a system of bosons coupled to the electromagnetic field of two optical cavities. For the specific configuration realized in a recent experiment at ETH [ 1 , 2 ], we show that, in absence of direct intercavity scattering and for parameters chosen such that the atoms couple symmetrically to both cavities, the system possesses an approximate U (1) symmetry which holds asymptotically for vanishing cavity field intensity. It corresponds to the invariance with respect to redistributing the total intensity $I={I}_{1}+{I}_{2}$ between the two cavities. The spontaneous breaking of this symmetry gives rise to a broken continuous translation-invariance for the atoms, creating a supersolid-like order in the presence of a Bose–Einstein condensate. In particular, we show that atom-mediated scattering between the two cavities, which favors the state with equal light intensities ${I}_{1}={I}_{2}$ and reduces the symmetry to ${{\bf{Z}}}_{2}\otimes {{\bf{Z}}}_{2}$ , gives rise to a finite value $\sim \sqrt{I}$ of the effective Goldstone mass. For strong atom driving, this low energy mode is clearly separated from an effective Higgs excitation associated with changes of the total intensity I . In addition, we compute the spectral distribution of the cavity light field and show that both the Higgs and Goldstone mode acquire a finite lifetime due to Landau damping at non-zero temperature.https://doi.org/10.1088/1367-2630/aa9b4asymmetry breakingsuperradianceGoldstone modesupersoliditycavity QEDultracold atoms |
| spellingShingle | J Lang F Piazza W Zwerger Collective excitations and supersolid behavior of bosonic atoms inside two crossed optical cavities New Journal of Physics symmetry breaking superradiance Goldstone mode supersolidity cavity QED ultracold atoms |
| title | Collective excitations and supersolid behavior of bosonic atoms inside two crossed optical cavities |
| title_full | Collective excitations and supersolid behavior of bosonic atoms inside two crossed optical cavities |
| title_fullStr | Collective excitations and supersolid behavior of bosonic atoms inside two crossed optical cavities |
| title_full_unstemmed | Collective excitations and supersolid behavior of bosonic atoms inside two crossed optical cavities |
| title_short | Collective excitations and supersolid behavior of bosonic atoms inside two crossed optical cavities |
| title_sort | collective excitations and supersolid behavior of bosonic atoms inside two crossed optical cavities |
| topic | symmetry breaking superradiance Goldstone mode supersolidity cavity QED ultracold atoms |
| url | https://doi.org/10.1088/1367-2630/aa9b4a |
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