Can temperature go lower than absolute zero kelvin ? It’s possible with statistical thermodynamics.
Consider a two-level system, for example magnetic dipoles in a magnetic field. Some of the dipoles may be aligned with the magnetic field while the rest are aligned opposite to the field. Those aligned with the field are at a lower energy level and those aligned opposite are at a higher energy level.
We can relate the number of dipoles of each type with energy and temperature this way :
So if there are more dipoles in the upper level than the lower level, we will have a negative thermodynamic temperature !
figkid 