Can we ever achieve absolute cold? PBS Space-Time investigates.
Many experimental physicists have spent their careers trying to cool things to absolute zero. This state of absolute cold is the zero-point on the Kelvin temperature scale, corresponding to -273.15 Celsius. Using lasers and magnetic fields, we’ve now managed to cool certain substances to less than a billionth of a Kelvin. Doing so has revealed some bizarre quantum states of matter. But quantum mechanics may also prevent us from ever reaching absolute zero. Understanding the limit to cold will lead us to an understanding of the nature of the quantum vacuum itself.