  We present improved circuits for the control-control-phase (Toffoli) gate and
the control-swap (Fredkin) gate using three and four global two-qubit gates,
respectively. This is a nearly double speed-up compared to the conventional
circuits, which require five (for Toffoli) and seven (for Fredkin) conditional
two-qubit gates. We apply the same approach to construct the conditional
four-qubit phase gate by seven global two-qubit gates. We also present
construction of the Toffoli and the Fredkin gates with five nearest-neighbour
interactions. Our constructions do not employ ancilla qubits or ancilla
internal states and are particularly well suited for ion qubits and for circuit
QED systems, where the entangling operations can be implemented by global
addressing.
