Nobel Prize-winning physicist Richard Feynman was the first to suggest that the mind-bending properties of quantum mechanics could be harnessed to make a new kind of computer. Almost 40 years later and after a decade of significant progress -- and after a claim by Google that its computer had reached a milestone known as “quantum supremacy” -- it’s still easier to describe the approach’s potential importance than to describe how it works. Understanding quantum mechanics, whose principles underpin quantum computing, involves a lot of mental mountain climbing — like something about a cat in a box that might or might not be dead?