Speaker
Description
Ultracold atoms represent a flexible platform for simulating topological and many-body phenomena of condensed matter and high-energy physics. The use of atomic dark states (long-lived superpositions of atomic internal ground states immune to atom-light coupling) offers new possibilities for such simulations. Making the dark states position-dependent, one can generate a synthetic magnetic field for ultracold atoms adiabatically following the dark states [1]. Recently, two-dimensional (2D) dark-state lattices were considered [ 2,3].
Here we present a general description of 2D topological dark state lattices elucidating an interplay with the sub-wavelength lattices [4]. In particular, we demonstrate that one can create a 2D Kronig-Penney lattice representing a periodic set of 2D subwavelength potential peaks affected by a non-staggered magnetic flux. Away from these patches of the strong magnetic field, there is a smooth magnetic flux of the opposite sign, compensating for the former peaks. While the total magnetic flux is zero, the system supports topological phases due to the flux variation over a unit cell, akin to Haldane-type lattice models with zero net flux over an elementary cell, but non-trivial topology due to non-zero fluxes over the plaquettes constituting the elementary cell. This work paves the way for experimental exploration of topological phases in dark-state optical lattices, offering new possibilities for simulating quantum Hall systems, fractional Chern insulators and related strongly correlated phases.
[1] N. Goldman, G. Juzeliūnas, P. Öhberg, and I. B. Spielman, Rep. Prog. Phys., 77,126401 (2014).
[2] E. Gvozdiovas, I. B. Spielman, and G. Juzeliūnas, Phys. Rev.. A, 107, 033328 (2023).
[3] S. Nascimbene and J. Dalibard, arXiv:2412.15038 (2024).
[4] D. Burba and G. Juzeliūnas, to be published.
