Scientists Recreate Quantum Electronics with Ultracold Atoms

Josephson junctions are essential for defining voltage standards and building quantum computers. However, their quantum behavior is extremely difficult to observe directly in solid materials. To address this, the team used two Bose-Einstein condensates separated by a thin optical barrier created with a focused laser. By moving the laser periodically, they mimicked the conditions of a superconducting Josephson junction. The atomic system produced the same defining signatures seen in real junctions, including Shapiro steps. These quantized voltage plateaus depend on fundamental constants and the driving frequency. Therefore, they form the basis for calibrating the global unit of voltage.

Making Quantum Processes Visible

Ultracold atoms offer a unique advantage: scientists can directly observe their movement. This allows visualization of quantum excitations that are otherwise hidden inside superconductors. The experiment confirms that Shapiro steps are a universal phenomenon. It also bridges the gap between electronic and atomic quantum systems.
Towards Atom-Based Quantum CircuitsLooking ahead, the researchers plan to connect multiple atomic junctions to form atom-based circuits, a field known as atomtronics. These circuits can replicate fundamental electronic components, but with atoms instead of electrons. As a result, scientists can study quantum coherence and microscopic behavior more precisely.This work represents a major advance in quantum simulation, showing that effects from solid-state physics can be recreated in entirely different systems while maintaining their core behavior.