Intermediate measurements aren’t a big deal for your normal, everyday computers, which can check the value of a variable any time the software calls for it. But in quantum computers, where measurement changes the state of a qubit, these checks are not so trivial.
In 2020, UChicago CS Assistant Professor Bill Fefferman and postdoctoral researcher Zachary Remscrim published a paper that proved you could move these intermediate requests to the end of an algorithm. In a new story, Quanta Magazine reporter Nick Thieme unpacks the significance of that finding, and how it could help today’s limited-memory quantum computers perform interesting calculations more easily.
“With this theoretical guarantee, researchers have a road map for translating their theory into applied algorithms,” Thieme writes. “Quantum algorithms are now free, in a sense, to proceed without the prohibitive costs of deferred measurements.”