Transient fault detectors for quantum circuits

In the last twenty years, transistors have been made smaller and smaller, in order to increase performance while reducing the area, as much as possible. Nowadays technologies have become more and more efficient. By the way, there is a threshold in the minimum size of the transistors that will be reached in a couple of years, which will cause a huge problem for the development of more powerful systems.?? A new computing paradigm has been proposed and is gaining a lot of attention: Quantum Computing. The latter can execute a certain task in several seconds rather than hundreds or even thousands of years as it happens on classical computer. These quantum computers are extremely powerful, but, unluckily, their reliability is very low, compromising their scalability. Cosmic rays are one of the main causes of this problem. They have been simulated by software, tuning the phase shift magnitude based on the proximity of the qubit to the particle strike location, to see how the fault is propagated on the circuit. To detect these particles, a specific circuitry, called Detector Barriers, has been designed. It is used to catch potential faults. The basic idea is to measure the barrier qubits always expecting the same bit string. Different barriers have been proposed, each of them can better detect different phase shifts caused by faults, on the qubits. According to these results, it is possible to understand that these extra gates, which are useless for elaboration, could be a good tool to improve the reliability of quantum computers.