The topological quantum computer still exists only in theory but, if possible, would be the most stable and powerful computing machine in the world. However, it requires a special type of qubit (quantum bit) that has yet to be realized and manipulated. The topological quantum computer still exists only in theory but, if possible, would be the most stable and powerful computing machine in the world. However, it requires a special type of qubit (quantum bit) that has yet to be realized and manipulated. Condensed Matter Quantum Physics Phys.org – latest science and technology news stories