  A scheme for implementing 2-qubit quantum controlled phase gate (QCPG) is
proposed with two superconducting quantum interference devices (SQUIDs) in a
cavity. The gate operations are realized within the two lower flux states of
the SQUIDs by using a quantized cavity field and classical microwave pulses.
Our scheme is achieved without any type of measurement, does not use the cavity
mode as the data bus and only requires a very short resonant interaction of the
SQUID-cavity system. As an application of the QCPG operation, we also propose a
scheme for generating the cluster states of many SQUIDs.
