Abstract: This presentation introduces unexpected physics that arises as one considers circuit design involving ultracold atoms rather than electrons. As a technology, atom circuitry iscomplementary to both electronics and photonics in problem-solving applicability (think clocks, quantum computers, and sensors). It is simply not so well developed, hence the interest in understanding the physics and developing engineering design principles. The ?new physics? enters with an inspiration from Maxwell's equations that asks about the properties of alternating (AC) matter currents. We know, of course, that alternating electric currents give rise to electromagnetic waves, and that generally the behavior of AC currents can be quite diHerent than the behavior of direct (DC) currents.