  In this letter we present a scheme for generating maximally entangled states
of two cavity modes which enables us to generate complete set of Bell basis
states having rather simple initial state preparation. Furthermore, we study
the interaction of a two-level atom with two modes of electromagnetic field in
a high Q cavity. The two-level atom acts as a control qubit and the two mode
electromagnetic field serves as a target qubit. This simple system of quantum
electrodynamics provides us experimentally feasible universal quantum logic
gates.
