  Several sequential operations are usually needed for implementing controlled
quantum gates and generating entanglement between a pair of quantum bits. Based
on the conditional quantum dynamics for a two-ion system beyond the Lamb-Dicke
limit, here we propose a theoretical scheme for manipulating two-qubit quantum
information, i.e., implementing a universal two-qubit quantum gate and
generating a two-qubit entangled state, by using a pair of simultaneous laser
pulses. Neither the Lamb-Dicke approximation nor the auxiliary atomic level are
required. The experimental realizability of this simple approach is also
discussed.
