In a mesoscopic conductor, electric resistance is detected even if the device is defect-free. We engineered and studied a cold-atom analog of a mesoscopic conductor. It consists of a narrow channel connecting two macroscopic reservoirs of fermions that can be switched from ballistic to diffusive. We induced a current through the channel and found ohmic conduction, even when the channel is ballistic. We measured in situ the density variations resulting from the presence of a current and observed that density remains uniform and constant inside the ballistic channel. In contrast, for the diffusive case with disorder, we observed a density gradient extending through the channel. Our approach opens the way toward quantum simulation of mesoscopic devices with quantum gases.
Philip Johannes Walter Moll, Matthias Carsten Putzke, Yi-Chiang Sun, Chunyu Guo, Jonas De Jesus Diaz Gomez, Maarten Ruud van Delft, Jacopo Oswald
Francesco Grilli, Nicolo' Riva, Arooj Akbar, Bertrand Dutoit
Sophia Haussener, Isaac Thomas Holmes-Gentle, Franky Esteban Bedoya Lora