P.S. On quantum supremacy

 Here it is explained pretty well what the Google quantum computer can do. It is actually quite impressive as a technological feat (they created a quantum circuit which has hundreds of two-qubit gates and high fidelity). But according to the authors, it does not achieve "quantum supremacy". We will see how the Google team and Aaronson will respond. But at least it is clear what the current quantum circuits can do.