Researchers from Griffith University and the University of Queensland have overcome one of the key challenges to quantum computing. They demonstrated this by experimentally realising a challenging circuit — the quantum Fredkin gate — for the first time.
The quantum Fredkin gate can also be used to perform a direct comparison of two sets of qubits (quantum bits) to determine whether they are the same or not.
For more information – here in the link from sciencedaily.com
The scheme is that it is not limited to just controlling whether qubits are swapped, but can be applied to a variety of different operation.