Israeli Physicists Approach Theoretical Limit of Computer Memory Energy Efficiency
Translated & summarized from NEWSru Israel by baba
Physicists at the Hebrew University of Jerusalem have created a novel memory cell that operates at an energy cost only five times the theoretical minimum, a significant leap from conventional chips. The cell uses a superconducting vortex, not a transistor, to store information as a 0 or 1. This breakthrough, published in Nature Communications, was achieved by carefully measuring the vortex's magnetic response at extremely low temperatures. While currently experimental and requiring cryogenic conditions, the technology could be applied to quantum computers.
The story in 6 lines · by baba
- Hebrew University physicists created a memory cell using superconducting vortices, operating near the theoretical energy limit.
- The new cell uses 5 times the minimum energy, compared to millions of times for standard chips.
- The research, published in Nature Communications, overcomes Landauer's 1961 energy dissipation limit for information.
- Measuring the vortex's magnetic response at 4 Kelvin was key to the experiment.
- The technology could store classical information in quantum computers.
- Co-author Nofar Friedman highlighted the experimental challenge of measuring the vortex's energy dissipation.
Physicists at the Hebrew University of Jerusalem have developed a memory cell that operates at an energy cost only five times the theoretical minimum, a significant improvement over conventional processors which consume millions of times more energy. In 1961, physicist Rolf Landauer established that erasing a single bit of information inevitably releases at least 3·10^-21 joules of heat. While this limit was initially overlooked due to its minuscule value, the immense scale of modern computing, with billions of transistors switching billions of times per second, makes energy dissipation a critical issue.
The new memory cell, detailed in Nature Communications, utilizes a superconducting vortex, a tiny magnetic flux "whirlpool" in certain materials at extremely low temperatures, instead of a transistor. Researchers have trapped a single vortex in a state with two stable positions, representing a 0 or a 1. This design allows the cell to approach Landauer's limit, consuming only about five times the minimum energy, a vast reduction from the millions of times more energy used by standard chips.
Measuring the minute energy dissipation was a significant experimental challenge. The heat generated by the vortex's movement is almost imperceptible. To overcome this, the researchers monitored the vortex's magnetic response using a highly sensitive microscope equipped with a superconducting quantum interference device (SQUID) at its tip. "The vortex is an extremely small and fragile object, so measuring the energy dissipated during its movement is a serious experimental task," explained co-author Nofar Friedman. "By tracking its magnetic response, we were able to compare the energy expenditure with the fundamental Landauer limit."
While the device currently operates at approximately 4 Kelvin (-269 °C), making it unsuitable for conventional computers, this temperature range is typical for quantum computers. These "vortex-based" memory cells could potentially store classical information within quantum processors.