The Cost of Forgetting

Landauer’s principle

An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• Erasing one bit releases at least $k_BT\ln 2 \approx 3 \times 10^{-21}$ J at room temperature.
• The erasure cost saves the second law from Maxwell’s demon.
• Only irreversible operations must pay it; today’s chips use thousands of times more.

Steps

1. Information is physical
2. One bit at room temperature
3. Erasing on a budget
4. Exorcising the demon
5. Real chips
6. Computing for free?