It was one thing for a quantum liquid like helium to exhibit divergences in properties like the specific heat near the critical temperature. Bagatskii, Voronel', and Gusak set out to measure the specific heat of a classical fluid (weakly-interacting argon) to obtain a more finely- resolved picture of the behavior very close to the critical point. Van der Waals' theory (and more generally, Landau's mean-field theory) yield finite discontinuities in the specific heat across the critical point, but the results obtained here suggested a much stronger divergence. With an eye on Fairbank, Buckingham, and Kellers' 1957 results for liquid helium, which had suggested a logarithmic singularity, Bagatskii, Voronel' and Gusak thought perhaps they were observing a similar logarithmic singularity. Voronel' and his colleagues performed similar experiments on nitrogen and oxygen which seemed to point to similar logarithmic singularities.

Was this an important experimental motive for rejecting incremental improvements in mean field theories as "good enough" for three dimensions?

Primary:

M. I. Bagatskii, A. V. Voronel', and V. G. Gusak, "Measurement of the specific heat c_v of argon in the immediate vicinity of the critical point," Soviet Physics JETP 16 (1963): 517-518; "Izmerenie teploemkosti c_v argona v neposredstvennoi blizosti k kriticheskoi tochke," ZhETF 43 (1962): 728-729.

A. V. Voronel', Yu. R. Chashkin, V. A. Popov, and V. G. Simkin, "Measurement of the specific heat c_v of oxygen near the critical point," Soviet Physics JETP 18 (1964): 568-569; "Izmerenie teploemkosti c_v kisloroda vblizi kriticheskoi tochki," ZhETF 45 (1963): 828-830.

A. V. Voronel' and M. Sh. Giterman, "Hydrostatic effect at the critical point of a binary alloy," Soviet Physics JETP 21 (1965): 958-; "Gidrostaticheskii effekt v kriticheskoi tochke binarnoi smesi," ZhETF 48 (1965): 1433-1436.

A. V. Voronel', V. G. Gorbunova, Yu. R. Chashkin, and V. V. Schekochikhina, "Specific heat of nitrogen at the critical point," Soviet Physics JETP 23 (1966): 597- 601; "Teploemkost' azota v okrestnosti kriticheskoi tochki," ZhETF 50 (1966): 897-904.

Secondary:

Ahlers 1980, 492.

Brush 1983, 254.

Domb 1996, 205.
--Karl Hall