# Physical significance of negative temperature

I read some answers regarding negative temperatures but I think my question is new. I want to know that what is the physical significance of negative temperature.

Suppose I say a body has temperature -2 K. Can I interpret it physically?

• I am a negative temperature "partisan" but it is important to mention that it is not everyone's cup of tea. The arxiv link can be found here. – gatsu Mar 16 '14 at 21:50
• @gatsu's position is also reflected in a Physics SE post pre-dating the paper he links: physics.stackexchange.com/q/76145 – dmckee Mar 16 '14 at 23:09

I think that the simplest way to wrap one's head around negative temperatures is that one: $$\beta = 1/T$$ The point is -- it is much more "physical" to describe a temperature of a body in terms of $\beta$. (We are using inverse of $\beta$ for a number of practical and historical reasons, but nevertheless.)
The larger that quantity $\beta$ -- the lower the temperature of a body. Notice that getting to absolute zero $T=0$ in that language means $\beta\to\infty$, making inaccessibility of it much more transparent.
On the other hand $\beta=0$ ($\Rightarrow T=\infty$) is not as restricted and you can go into negative values of $\beta$, thus getting negative (and very large) values of $T$.