  In a recent article [http://dx.doi.org/10.1103/PhysRevA.87.022340, Phys. Rev.
A 87, 022340 (2013)], Yan et al have studied geometric discord for a well known
class of bound entangled states. Based on their calculation, they claim "It is
found that there exists a nondynamic sudden change in quantum discord" for
these states. In this Comment, we criticize their work by pointing out that
what has been calculated is actually a bound, and not the exact value of
discord. Since, generally, it is not possible to infer the exact value (or
property) of a quantity just from its bound, we can not conclude about (exact)
discord and its change. Thus, the above-mentioned conclusion can not be drawn
from the calculations of the paper.

Quantum Physics