Researchers have found a way to test how accurate the answers are returned by a quantum computer.
In order to maximize the benefits of quantum computers, you need to be able to validate the data.
The authors of the new work thought about this problem and created a new way of cross-validation: it allows you to verify the results of a calculation performed on one device by calculating the same data on another device: it is important that the calculation algorithm is not completely similar to the original one.
The authors used an alternative model of quantum computing, built on graph structures: in this way, many different alternative computations can be generated from a common source in order to verify the results of a quantum computer.
The researchers noted that there are certain outputs that need to be matched if the devices are working properly.
The team tested their method on five modern quantum computers using four different hardware technologies.
The new approach works on modern equipment without any special requirements. Another important advantage is that researchers do not need to look at all the results of the calculations, as this can be very time-consuming. It is enough to check how often both devices agree at intermediate stages and in the end. This can be done even for very large quantum computers.