It is a sunny Tuesday morning in late March at IBM's Thomas J. Watson Research Center. The corridor from the reception area follows the long, curving glass curtain-wall that looks out over the visitors' parking lot to leafless trees covering a distant hill in Yorktown Heights, New York, an hour north of Manhattan. Walk past the podium from the "Jeopardy!" episodes at which IBM's Watson smote the human champion of the TV quiz show, turn right into a hallway, and you will enter a windowless lab where a quantum computer is chirping away.