Having recently posted a general piece about spin in general (https://physbang.com/2024/11/24/what-is-spin/) I thought it would be useful to discuss one particular use of spin in a practical context; cooling. Suppose we have a material with a single unpaired electron in each of its atoms. The lone electrons can either be spin-up or spin-down and on … Continue reading Spin Cooling
Absolute Zero
Where does the idea of "absolute zero" come from? In part it stems from a need to avoid negative temperatures but a better explanation can be found by thinking about the kinetic theory of gases. When a gas is heated, its particles gain kinetic energy. This in turn means that the particles have a higher … Continue reading Absolute Zero
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