By creating a protocol that allows a quantum computer to check its own answers to difficult problems, researchers from the University of Warwick have provided a means to confirm that a quantum computer is working correctly without excessive use of resources.
The team has developed a protocol to quantify the effects of noise on the outputs of quantum computers. Noise is defined as anything that affects a quantum machine’s hardware but is beyond the user’s control, such as fluctuations in temperature or flaws in the fabrication. Noise affects the accuracy of a quantum computer’s results.
The researchers have proposed an alternative method that involves using the quantum computer to run a number of easy calculations that we already know the answer to and establishing the accuracy of those results. Based on this, the researchers can put a statistical boundary on how far the quantum computer can be from the correct answer in the difficult problem that we want it to answer, known as the target computation. (University of Warwick)