  Dielectric constant and absorption measurements on boron doped silicon
samples show that transitions between the acceptor energy levels can be induced
by an applied resonant ac electric field and the Stark tuning of level spacing
with an external DC electric field. The relatively longer decoherence times
were observed by the electric echo measurement in a low boron dopant
concentration Si sample. The scalable acceptor-based system is a promising
candidate of the charge qubit for quantum computing.
