Physicists at the Hebrew University of Jerusalem have calculated that a single superconducting vortex can operate as a memory bit at roughly five times Landauer's theoretical minimum. Led by Yonathan Anahory, the research team utilized a nanoscale whirlpool of electrical current to store data values based on physical positioning.
The experimental setup involved a 55-nanometer niobium film patterned into a 10-micrometer-wide strip and cooled to 4.2 kelvin, or minus 269 degrees Celsius. By sweeping a steady current through the material, researchers nudged individual vortices into resting spots just nanometers apart, effectively designating left and right positions as binary zero and one. Using a SQUID-on-tip magnetic sensor, the team tracked energy dissipation during cycles of alternating current, anchoring their efficiency estimates to continuous-drive measurements and numerical simulations.
Despite approaching the absolute efficiency floor dictated by physics, the architecture faces notable constraints. The impressive energy metrics exclude the substantial power demands of the cryogenic refrigeration needed to maintain liquid-helium temperatures. Furthermore, the operational speed of 150 kHz falls significantly behind modern computing standards, while thermal noise introduces stability challenges for data retention.
Comments