Physics & AstronomyJanuary 31: John Lacy, Postdoctoral Research Fellow, Williams College, "Making Use of Imperfect Perfect Connectors."

Superconductivity – the phenomenon of electrical conduction with precisely zero resistance –
seems like the stuff of science fiction. Not only can a closed superconducting loop sustain
electrical power without any measurable decay (you would have to wait a time longer than the
age of the universe to observe any change!), but their properties can also be harnessed to
levitate trains, propel aircraft, and generate extremely high magnetic fields. The latter has a
whole range of applications, including in medicine, defense, and fundamental science. As an
atomic physicist by training, I first became interested in superconductivity as a subsidiary
project when I was designing an apparatus to trap and detect individual electrons for quantum
microwave detection. During that time, I learned that superconductors are not always perfect,
and in certain circumstances they can exhibit small but finite resistances. In this talk, I will
discuss the importance of imperfect superconductors, and will introduce the rapidly growing
field of flux pumping, whereby imperfect superconductivity can be exploited to generate
extremely clean and efficient electrical power in a wireless fashion.