Quantum Statistics and the Many-Body Problem pp 205-206 | Cite as

# Thermal Expansion Coefficient and Universality Near the Superfluid Transition of ^{4}He under Pressure

Chapter

## Summary

Recent measurements
for T > T

^{1}of the specific heat C_{p}of pressurized liquid helium near the λ-line gave results which seemed to be in conflict with the concept of universality;^{2}specifically the amplitude ratio A/A’ of the singular part of C_{p}above and below T_{λ}appeared to depend upon the pressure P.^{1}We report on new determinations of A/A’ for^{4}He near T_{λ}based upon measurements of the isobaric thermal expansion coefficient ß_{p}^{3}, which is a linear function of C_{p}sufficiently near T_{λ}. Our measurements were made by a new technique, to be described in detail elsewhere,^{3}which is characterized by high pressure stability (ΔP/P ≲ 2.10^{−8}), and temperature resolution (ΔT/T ≈ 2·10^{−7}). Our experiment covered the ranges 5 bar ≤ P ≤ 29 bar, and 2·10^{−5}≤ |t| ≤ 0.07, where t = T/T_{λ}− 1. The data were fit to$$
{\beta _p} = (A/\alpha ) {t^{ -\alpha }}[1 + D {t^x}] + B
$$

_{λ}, and simultaneously to the same function with primed coefficients for T < T_{λ}.## Keywords

Thermal Expansion Quantum Statistics Theoretical Prediction Excellent Agreement Thermal Expansion Coefficient
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

## References

- (1).G. Ahlers, Phys. Rev. A8, 530 (1973).ADSGoogle Scholar
- (2).See, for instance, L. P. Kadanoff, in Critical Phenomena, Proceedings of the International School Enrico Fermi, Course L1, edited by M. S. Green (Academic Press, N.Y., 1971);Google Scholar
- R. B. Griffiths, Phys. Rev. Lett. 24, 1479 (1970);ADSCrossRefGoogle Scholar
- D. Jasnow and M. Wortis, Phys. Rev. 176, 739 (1968)ADSCrossRefGoogle Scholar
- E. Brezin, J. C. Guillou, and J. Zinn-Justin, Phys. Lett. 47A, 285 (1974).ADSGoogle Scholar
- (3).K. H. Mueller, F. Pobell, and G. Ahlers, Phys. Rev. Lett. 34, 513 (1975), and to be published in Phys. Rev.ADSCrossRefGoogle Scholar

## Copyright information

© Plenum Press, New York 1975