Topological charge pumping with subwavelength Raman lattices
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arXiv
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| Autori principali: | , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2022
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| _version_ | 1866912665300893696 |
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| author | Burba, Domantas Račiūnas, Mantas Spielman, Ian B. Juzeliūnas, Gediminas |
| author_facet | Burba, Domantas Račiūnas, Mantas Spielman, Ian B. Juzeliūnas, Gediminas |
| contents | Recent experiments demonstrated deeply subwavelength lattices using atoms with $N$ internal states Raman-coupled with lasers of wavelength $λ$. The resulting unit cell was $λ/2N$ in extent, an $N$-fold reduction compared to the usual $λ/2$ periodicity of an optical lattice. For resonant Raman coupling, this lattice consists of $N$ independent sinusoidal potentials (with period $λ/2$) displaced by $λ/2N$ from each other. We show that detuning from Raman resonance induces tunneling between these potentials. Periodically modulating the detuning couples the $s$- and $p$-bands of the potentials, creating a pair of coupled subwavelength Rice--Mele chains. This operates as a novel topological charge pump that counter-intuitively can give half the displacement per pump cycle of each individual Rice--Mele chain separately. We analytically describe this behavior in terms of infinite-system Chern numbers, and numerically identify the associated finite-system edge states. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2210_05515 |
| institution | arXiv |
| publishDate | 2022 |
| record_format | arxiv |
| spellingShingle | Topological charge pumping with subwavelength Raman lattices Burba, Domantas Račiūnas, Mantas Spielman, Ian B. Juzeliūnas, Gediminas Quantum Gases Recent experiments demonstrated deeply subwavelength lattices using atoms with $N$ internal states Raman-coupled with lasers of wavelength $λ$. The resulting unit cell was $λ/2N$ in extent, an $N$-fold reduction compared to the usual $λ/2$ periodicity of an optical lattice. For resonant Raman coupling, this lattice consists of $N$ independent sinusoidal potentials (with period $λ/2$) displaced by $λ/2N$ from each other. We show that detuning from Raman resonance induces tunneling between these potentials. Periodically modulating the detuning couples the $s$- and $p$-bands of the potentials, creating a pair of coupled subwavelength Rice--Mele chains. This operates as a novel topological charge pump that counter-intuitively can give half the displacement per pump cycle of each individual Rice--Mele chain separately. We analytically describe this behavior in terms of infinite-system Chern numbers, and numerically identify the associated finite-system edge states. |
| title | Topological charge pumping with subwavelength Raman lattices |
| topic | Quantum Gases |
| url | https://arxiv.org/abs/2210.05515 |