  We present a continuous time quantum search algorithm analogous to Grover's.
In particular, the optimal search time for this algorithm is proportional to
$\sqrt{N}$, where $N$ is the database size. This search algorithm can be
implemented using any Hamiltonian with a discrete energy spectrum through
excitation of resonances between an initial and the searched state. This
algorithm is robust and, as in the case of Grover's, it allows for an error
$O(1/\sqrt{N})$ in the determination of the searched state. A discrete time
version of this continuous time search algorithm is built, and the connection
between the search algorithms with discrete and continuous times is
established.
