Singularity in entanglement negativity across finite-temperature phase transitions

Phase transitions at a finite (i.e. nonzero) are typically driven by classical fluctuations, as opposed to those at zero temperature where quantum mechanics plays an essential role. Motivated by this observation, here we ask whether there exist any universal signatures of quantum correlations across a finite temperature phase transition? In this work, we approach this question by investigating one measure of quantum correlations at finite temperature, called `entanglement negativity', in several models that exhibit phase transition.