  The ATLAS experiment at CERN relies on a worldwide distributed computing Grid
infrastructure to support its physics program at the Large Hadron Collider.
ATLAS has integrated cloud computing resources to complement its Grid
infrastructure and conducted an R&D program on Google Cloud Platform. These
initiatives leverage key features of commercial cloud providers: lightweight
configuration and operation, elasticity and availability of diverse
infrastructure. This paper examines the seamless integration of cloud computing
services as a conventional Grid site within the ATLAS workflow management and
data management systems, while also offering new setups for interactive,
parallel analysis. It underscores pivotal results that enhance the on-site
computing model and outlines several R&D projects that have benefited from
large-scale, elastic resource provisioning models. Furthermore, this study
discusses the impact of cloud-enabled R\&D projects in three domains:
accelerators and AI/ML, ARM CPUs and columnar data analysis techniques.
