From vast data cen­ters to mobile phones, the pow­er of com­put­ers con­tin­ues to trans­form our lives. But there are some prob­lems across arti­fi­cial intel­li­gence, in the design of new mate­ri­als, phar­ma­ceu­ti­cals, and clean ener­gy devices that they will sim­ply nev­er solve. So even if we turned our entire plan­et into a giant super­com­put­er we would­n’t be able to solve these and many oth­er impor­tant prob­lems. The good news is that if we could build a com­put­ing device based on fun­da­men­tal quan­tum prin­ci­ples, we could.