  We present a way to create entangled states of two superconducting transmon
qutrits based on circuit QED. Here, a qutrit refers to a three-level quantum
system. Since only resonant interaction is employed, the entanglement creation
can be completed within a short time. The degree of entanglement for the
prepared entangled state can be controlled by varying the weight factors of the
initial state of one qutrit, which allows the prepared entangled state to
change from a partially entangled state to a maximally entangled state. Because
a single cavity is used, only resonant interaction is employed, and none of
identical qutrit-cavity coupling constant, measurement, and auxiliary qutrit is
needed, this proposal is easy to implement in experiments. The proposal is
quite general and can be applied to prepare a two-qutrit partially or maximally
entangled state with two natural or artificial atoms of a ladder-type level
structure, coupled to an optical or microwave cavity.
