“The needle moved!” one can imagine Hans Christian Ørsted exclaiming aloud when he energized the nearby wire, discovering electromagnetism. Just as easily, one can imagine Niels Bohr wondering aloud a century later, “And what if there had been no needle? Would there still have been a magnetic field?” or even, “What if the needle was there, but Ørsted was not there to observe it?” The legacies of Ørsted and Bohr, respective discoverers of classical electromagnetism and quantum physics, connect today, at the research frontier, where the flow of electric currents and the fields that result can remain in an undetermined quantum state until measured. Perhaps most surprising is that adding quantum indeterminacy to electromagnetism raises new and difficult unanswered questions and hints at unrealized technologies. This talk presents the entangled legacies of Ørsted and Bohr and what it means for modern research and our future practical world.
