Quantum computers: Trust is good, proof is better

A quantum computer can solve tasks where a classical computer fails. The question how one can, nevertheless, verify the reliability of a quantum computer was recently answered in an experiment at the University of Vienna. The conclusions are published in the reputed scientific. The harnessing of quantum phenomena, such as superposition and entanglement, holds great promise for constructing future supercomputers using quantum technology. One huge advantage of such quantum computers is that they are capable of performing a variety of tasks much quicker than their conventional counterparts. The use of quantum computers for these purposes raises a significant challenge: how can one verify the results provided by a quantum computer? It is only recently that theoretical developments have provided methods to test a quantum computer without having an additional quantum computer at hand. The international research team around Philip Walther at the University of Vienna has now demonstrated a new protocol, where the quantum computational results can be verified without using additional quantum computer resources.