Comment on “Frequency dependence and equilibration of the specific heat of glass-forming liquids”

In a recent publication C. C. Yu and H. M. Carruzzo [Phys. Rev. E 69, 051201 (2004)] determined that the minimum sampling time to calculate the specific heat in a supercooled liquid using energy fluctuations is on the order of 10(3) alpha relaxation times, which is much longer than the sampling time used in most simulations. We demonstrate how the specific heat can be calculated from simulations run to 15 alpha relaxation times, and use statistical arguments to explain the systematic deviation of the specific heat calculated from a simulation of finite length from the true expectation value of the specific heat.