I know that for two symmetric positive semi-definite (non-diagonal) matrices $A,B$, the inequality asserts that the following does not hold for all $p > 1$
$$A \succeq B \succeq 0 \Rightarrow A^p \succeq B^p $$
I would like to know if there are results, which say under what conditions of $A,B$ (e.g., looking at a particular space of the the matrices etc.) the inequality would hold, and in particular, for $p = 2$? Thanks.