AN ALL-POWERFUL QUANTUM JUICER

Suppose you own a health food shop and you want to offer customers a variety of juices. Apple, orange, grapefruit, carrot, beet, wheatgrass – something for any appetite you might encounter.

Now imagine that each type of fruit or vegetable requires its own specific juicing equipment. To make apple juice, you need an apple juicer. For carrot juice, a carrot juicer. And so on. The investment required would gobble up your profits, and you’d be ill-prepared to capitalize on the latest trendy superfruits.

Now, if you want to make anything – from a manufactured product to a new kind of computer – you have to consider the required resources systematically. That’s called resource theory. For quantum computing and quantum experiments, you use quantum resource theory. Until recently, the study of quantum resource theory mostly targeted single fruits. Each type of quantum “resource” – entanglement, for example – was like a different type of fruit, for which a corresponding juicer (or resource theory) must be developed.

Zi-Wen Liu

That’s about to change, thanks to recent work by Perimeter postdoctoral researcher Zi-Wen Liu and collaborators Kaifeng Bu (Zhejiang University and Harvard University) and Ryuji Takagi (Massachusetts Institute of Technology). The trio developed a framework – the rough quantum equivalent of a multipurpose juicer – that can characterize the practical usefulness of any quantum resource, regardless of type.

The paper, published in Physical Review Letters, was highlighted as an Editor’s Suggestion. Liu’s work is expected to have broad applicability to fields that use quantum resources, like quantum computing and quantum information.

“My way of looking at resource theory is that I just wanted to develop the most powerful juicer with the most functions,” said Liu.