  Erasure of information stored in a quantum state requires energy cost and is
inherently an irreversible operation. If quantumness of a system is physical,
does erasure of quantum correlation as measured by discord also need some
energy cost? Here, we show that change in quantum correlation is never larger
than the total entropy change of the system and the environment. The entropy
cost of erasing correlation has to be at least equal to the amount of quantum
correlation erased. Hence, quantum correlation can be regarded as genuinely
physical. We show that the new bound leads to the Landauer erasure. The
physical cost of erasing quantum correlation is well respected in the case of
bleaching of quantum information, thermalization, and can have potential
application for any channel leading to erasure of quantum correlation.
