Conciousness requires constant processing of a changing stimulus. It exists at a single point in the logical mind where the most important object of the moment is constantly focused upon. When there is nothing physical or external to focus upon, we delve into our imagination to fill the gap.
AI cannot be conscious, by this definition, because it is not responsible for determining what it should use fill this void. Rather, it simply blinks in and out of "existence" like a flash, in response to our queries.
The ultimate measure of consciousness is whether an AI can alone collapse a quantum superposition.