Traditionally, optical lattices are created by interfering two or more light beams, so atoms are trapped at minima or maxima of the emerging interference pattern depending on the sign of the atomic polarizability [1]. The characteristic distances over which such lattice potentials change are limited by diffraction and thus cannot be smaller than half of the optical wavelength λ. The diffraction limitation can be overcome, and subwavelength lattices can be created using coherent coupling between atomic internal states [2-9]. In particular, recent experiments demonstrated deeply subwavelength lattices using atoms with N internal states Raman-coupled with lasers of wavelength λ [7]. The resulting unit cell was N times smaller compared to the usual λ/2 periodicity of an optical lattice.

In the present talk we will discuss various ways to produce subwavelength lattices and effects manifesting in these lattices. In particular, the atom-atom interaction is unusual and extends over a longer range, leading to novel many-body phases [10].

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[2] M. Łącki et al., Phys. Rev. Lett. 117, 233001 (2016).
[3] F. Jendrzejewski et al., Phys. Rev. A 94, 063422 (2016).
[4] Y. Wang et al, Phys. Rev. Lett. 120, 083601 (2018).
[5] E. Gvozdiovas, P. Račkauskas, G. Juzeliūnas, SciPost Phys. 11, 100 (2021).
[6] P. Kubala, J. Zakrzewski and M. Łącki, Phys. Rev. A 104, 053312 (2021).
[7] R. P. Anderson et al, Physical Review Research 2, 013149 (2020).
[8] D. Burba, M. Račiūnas, I. B. Spielman and G. Juzeliūnas, Phys. Rev. A 107, 023309 (2023).
[9] E. Gvozdiovas, I. B. Spielman and G. Juzeliūnas, Phys. Rev. A 107, 033328 (2023).
[10] D. Burba, G. Juzeliūnas, I. B. Spielman and L. Barbiero, arXiv:2409.01443 (2024).