  We theoretically study the crossed Andreev reflection in a hybrid
nanostructure which comprises a d-wave superconductor and two normal-metal
quantum wires. When the superconductor of the (110) oriented surface is in
contact with the wires parallel and placed close to each other, the Andreev
bound state is formed by the crossed Andreev reflection. When the contact
barrier potential is sufficiently large, two sharp peaks appear in the
conductance well below the gap structure, which originate from the bonding and
antibonding Andreev bound states. We propose that these Andreev bound states
form a two-level quantum system (qubit).
