  For the Josephson junction charge qubits with macroscopically quantum
natures, we propose a theoretical scheme to observe the loss of quantum
coherence through coupling such qubit system to an engineered reservoir, the
harmonic oscillator mode in the LC circuit formed by the inductor and the
separated capacitors. Similar to the usual cavity QED system in form, this
charge qubit system with engineered couplings shows the quantum jumps (C.P.Sun
et al Fortschr. Phys. \textbf{43}, 585 (1995))in a progressive decoherence
process. Corresponding to two components of superposition of two charge states,
the inductor evolves simultaneously towards two distinct quasi-classical states
entangling with two states of the charge qubit. Then it induces the quantum
decoherence for the induced squeezing macroscopically in the LC mode.
