Experimental characterization of the photonic quantum Fredkin gate

The quantum Fredkin gate is a three-qubit gate that swaps the two target qubits if and only if the control qubit is in the logical state |1). The gate finds various applications in quantum computing [1, 2], communications [3] and measurement schemes [4]. We present photonic implementation of the quantum Fredkin gate and its full tomographical characterization, along with other demonstrations of its functionality.