The agency has promoted Paul Bennett, its current director of e-commerce, to the role of managing director.
Arena Quantum will offer digital business services including bespoke technology build, content development and e-commerce strategy. It will also offer insight for Arena Media's clients that are using core digital media channels such as paid search, display and social media.
The change to Arena Quantum is part of a refresh of Arena Media's agency positioning. It includes the launch of a new tool called Architect, which incorporates behavioural economics into the planning process.
Dan Clays, Arena Media's chief strategy officer, said: "We are an agency restless to stay ahead, but still rooted in performance; and our new positioning, 'partners for now and next', reflects that."