Quantum gas magnification of ultracold atoms in optical lattices

Abstract Ultracold atoms in optical lattices are a very promising quantum simulation platform, as they provide a very clean system (almost defect free) and allow control over many parameters such as tunneling coupling or interaction strength. Because the typical lattice spacing lies in the sub-micron range, it is technically demanding to resolve exactly the position of the atoms in the lattice using high-resolution optics such as quantum gas microscopy. Here we review the matter-wave protocol of quantum gas magnification that we developed for magnifying the atomic density distribution in the lattice (Asteria et al 2021 Nature 599 571). The atomic cloud, thus magnified by a factor of up to <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mrow> <mml:mo>∼</mml:mo> </mml:mrow> <mml:mn>90</mml:mn> </mml:mrow> </mml:math> , can then be imaged in a single-shot even with sub-lattice resolution with standard absorption imaging techniques. Furthermore, the protocol was demonstrated for 3D systems with high filling factors, which are typically impossible to measure with high-resolution imaging. In this tutorial, we will review how this technique can be used for high-resolution imaging of the density distribution and present the results obtained using it as a method to access new observables. We conclude with an outlook focusing on how this technique could be beneficial for a wide variety of physical systems which can be realized using cold atoms. This tutorial expands on the topic of my presentation for the SAMOP 2023 PhD Prize finalist symposium.