Researchers cut computing heat waste by 60 percent

Good news!

"In brief

• A SLAC-Stanford team developed a new way to precisely measure just how much energy has dissipated into heat in a liquid crystal device.
• By controlling how they applied energy to a system, the researchers reduced waste heat by more than 60 percent.
• The method could inform design of future computers and other electrical devices to make them more energy efficient.

...

Researchers ... developed a new way to measure just how much energy has dissipated into heat in an electrical system.

The team ... also optimized the shape of the voltage pattern used to control the device, which reduced the waste heat by more than 60 percent. ...

team used a liquid crystal device as a model system and took a new approach: They injected clean electrical signals into the device and calculated the dissipation from electrical measurements alone, correlated with optical measurements of the dynamical switching processes occurring within the liquid crystals. ...

The team then took their experiment a step further and used machine learning ... to optimize their process to create the least amount of wasted energy. They found that if they ramped up the voltage quickly, then slowed the increase for a fraction of a second, then sped it up again, more than 60 percent less energy was wasted. ..."

From the abstract:

"In a finite-time continuous phase transition, topological defects emerge as the system undergoes spontaneous symmetry breaking. The Kibble-Zurek mechanism predicts how the defect density scales with the quench rate. During such processes, dissipation also arises as the system fails to adiabatically follow the control protocol near the critical point.

Quantifying and minimizing this dissipation is fundamentally relevant to nonequilibrium thermodynamics and practically important for energy-efficient computing and devices. However, experimentally measuring dissipation, and optimizing control protocols to reduce it, remains almost completely unexplored. In addition, it is an open question to what extent dissipation is correlated with the formation of defects.

Here, we directly measure the dissipation generated during the voltage-driven Fréedericksz transition of a liquid crystal with a sensitivity equivalent to a ∼10 nanokelvin temperature rise.

We observe Kibble-Zurek scaling of dissipation and its breakdown, both in quantitative agreement with existing theoretical works. We further implement a fully automated in situ optimization approach that discovers more optimal driving protocols, reducing dissipation by a factor of 3 relative to a simple linear protocol."

Researchers cut computing heat waste by 60 percent | Stanford Report "Using liquid crystals as a model, a SLAC-Stanford team developed a precise method to measure energy dissipation in electrical models. The technique could inform the design of more energy-efficient computers."

Quantifying and Minimizing Dissipation in a Nonequilibrium Phase Transition (no public access)

Quantifying and minimizing dissipation in a non-equilibrium phase transition (preprint, open access)