  We present a model for quantum computation using n steady 3-level atoms or
3-level quantum dots, kept inside a quantum electro-dynamics (QED) cavity. Our
model allows one-qubit operations and the two-qubit controlled-NOT gate as
required for universal quantum computation. The n quantum bits are described by
two energy levels of each atom/dot. An external laser and n separate pairs of
electrodes are used to address a single atom/dot independent of the others, via
Stark effect. The third level of each system and an additional common-mode
qubit (a cavity photon) are used for realizing the controlled-NOT operation
between any pair of qubits. Laser frequency, cavity frequency, and energy
levels are far off-resonance, and they are brought to resonance by modifying
the energy-levels of a 3-level system using the Stark effect, only at the time
of operation.
