Logarithmic singularity of specific heat in liquid helium II at the λ point

Abstract

The experimental width of the second sound peak in Brillouin scattering is less than the instrumental width. It is also less than the width of the first sound peak near the λ point. The theoretical width of the second sound peak becomes infinitely large at the λ point in the traditional viewpoint. This discrepancy suggests that the second sound peak detected in Brillouin scattering is an elementary excitation. We calculate the specific heat of liquid helium near the λ point by considering the second sound peak. The calculated temperature-dependence of the specific heat has a logarithmic divergence at the λ point. Furthermore, the calculated values of the specific heat agree well with data derived from experiments. © Springer Science+Business Media, LLC 2007.