Quantum effects near the liquid-vapour critical point

We gather together a number of recent measurements of the coexistence curve and compressibility of fluids close to the critical point, and investigate the variation of the critical exponents and amplitudes as quantum effects become more important. We find that the universal critical exponents and amplitude ratios are the same for quantum fluids as for room-temperature fluids, as expected. Some of the nonuniversal critical amplitudes, however, show systematic variations as quantum effects become significant, in at least qualitative agreement with theoretical predictions