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.
Francesco Grilli, Nicolo' Riva, Arooj Akbar, Bertrand Dutoit
Philip Johannes Walter Moll, Matthias Carsten Putzke, Yi-Chiang Sun, Chunyu Guo, Jonas De Jesus Diaz Gomez, Maarten Ruud van Delft, Jacopo Oswald
Sophia Haussener, Isaac Thomas Holmes-Gentle, Franky Esteban Bedoya Lora