We may finally have a way to rate a quantum computer’s usefulness

How useful is a particular quantum computer? We may finally be able to answer this question.

Quantum computers have made significant strides in recent years, becoming both more reliable and powerful. Yet, when it comes to computations that could have a large impact on the world, such as understanding the FeMoco molecule, which plays a key role in nitrogen fixing, or breaking today’s most prevalent cryptography methods, quantum computers still underperform.

But assessing how far they are from being sufficiently capable has always been tricky. Now, Timothy Proctor at Sandia National Laboratories in California and his colleagues say their QUOPS score is the missing piece of the puzzle.

The idea is relatively simple. First, a quantum computer runs a special set of programs, or quantum circuits, which allow researchers to calculate its QUOPS score. QUOPS stands for quantum universal operation performance system, and reflects how many physical building blocks, or qubits, the quantum computer has and how many computational operations it can execute. This number can then be compared with the QUOPS score for an algorithm that researchers may wish to run on this quantum computer.

If the algorithm’s score is larger than the computer’s, the computation won’t work. But if the quantum computer’s score is comparable or larger, then the machine ought to be useful for solving the problem that the algorithm was designed for. Another number, the QUOPS rate, captures how long that computation would take.