In our experiments, we generate arrays of up to 50 optical tweezers arranged in arbitrary two-dimensional geometries, each containing a single cold atom, and separated by distances of a few micrometers. This is achieved by active sorting of atoms in larger arrays that are initially loaded stochastically [1]. By exciting the atoms to Rydberg states (with principal quantum numbers in the range 50–100), we can induce strong, tunable dipolar interactions between the atoms [2].
This system is an ideal platform for the quantum simulation of spin Hamiltonians. By using van der Waals interactions we can implement the quantum Ising model in a transverse field and observe the dynamics of the magnetization and of correlation functions following a quantum quench [3]. Using resonant dipole-dipole interactions, we observed the propagation of a spin excitation in a minimalistic spin chain governed by the XY Hamiltonian [4,5].
References
[1] D. Barredo et al., Science 354, 1021 (2016).
[2] A. Browaeys, D. Barredo, and T. Lahaye, J. Phys. B 49, 152001 (2016).
[3] H. Labuhn et al., Nature 534, 667 (2016).
[4] D. Barredo et al., Phys. Rev. Lett. 114, 113002 (2015).
[5] S. de Léséleuc et al., Phys. Rev. Lett. 119, 053202 (2017).
LCF, CNRS and Institut d’Optique, Palaiseau, France