So basically, bad code causes slowdowns?
No, because there is no code.
It's a "quantum annealing" machine, which is something like a cooling metal, only with configurable strengths between the configuration elements (think analog computer doing neural networks or spin glass annealing), and with more quantum sauce.
I also notice that there are two Google Guys/Gals in the list of authors:
> Troels F. Rønnow - Theoretische Physik, ETH Zurich
> Zhihui Wang - Department of Chemistry, University of Southern California
> Joshua Job - Center for Quantum Information Science and Technology & Department of Physics, University of Southern California
> Sergio Boixo - Google, 150 Main Street, Venice Beach, California
> Sergei V. Isakov - Google, Brandschenkestrasse 110, Zurich
> David Wecker - Quantum Architectures and Computation Group, Microsoft Research, Redmond
> John M. Martinis - Department of Physics, University of California Santa Barbara
> Daniel A. Lidar - Department of Chemistry & Center for Quantum Information Science and Technology & Department of Physics, University of Southern California
> Matthias Troyer - Theoretische Physik, ETH Zurich