Interaction-driven losses for atoms in a dark-state lattice

In this work we estimate the collisional loss rate of ultracold bosons in the optical potential featuring subwavelength-width peaks. This is established by using $\Lambda$ arrangement of three atomic states coupled (almost) resonantly by lasers. Using Fermi's Golden Rule, we find that the loss rate is influenced by the overall strength of the lasers, with the largest losses occurring when the two-photon transition is blue-detuned from the excited state of the $\Lambda$ system. Overall, the predicted loss rates are low, which may allow the use of ultracold bosons in the construction of dark-state potentials in the $\Lambda$-type many-level system.