Physicists demonstrate a quantum Fredkin gate
Researchers from Griffith University and the University of Queensland have overcome one of the key challenges to quantum computing by simplifying a complex quantum logic operation. We demonstrate in our experiment how one can build larger quantum circuits in a more direct way without using small logic gates. This is a gate where two qubits are swapped depending on the value of the third. Usually the Fredkin gate requires implementing a circuit of five logic operations. The research team used the quantum entanglement of photons—particles of light—to implement the controlled-SWAP operation directly.