Optimizing Pre-formed Molecules in Mixtures of Ultracold 40K and 87Rb on an Optical Lattice: A Challenge Grant and Capabilities Application Project

This work is part of a Defense Advanced Research Projects Agency (DARPA) sponsored project to build an optical lattice emulator, where models of strongly correlated electrons in condensed matter physics are simulated with ultracold atoms moving in an optical lattice. Recently, members of our team have been able to form dense clouds of dipolar fermionic molecules from mixtures of (fermionic) ⁴⁰K and (bosonic) ⁸⁷Rb. Here, we use high performance computing (HPC) resources to find a way to improve the efficiency of molecule formation from the current 20% to almost 100% and thereby show how to create a much denser cloud of dipolar molecules. Our code scales nearly linearly on up to 4,000 (or more) processors, and runs at an efficiency that is almost at 100% of the speed for one arithmetic operation per clock cycle. We have not been able to get the code to run with multiple operations per clock cycle in spite of using highly efficient and optimized libraries for BLAS and LAPACK.