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Thermal Expansion Coefficient and Universality Near the Superfluid Transition of 4He under Pressure

  • K. H. Mueller
  • F. Pobell
  • Guenter Ahlers

Summary

Recent measurements1 of the specific heat Cp 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 Cp above and below Tλ appeared to depend upon the pressure P.1 We report on new determinations of A/A’ for 4He near Tλ based upon measurements of the isobaric thermal expansion coefficient ßp 3, which is a linear function of Cp sufficiently near Tλ . 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/Tλ − 1. The data were fit to
$$ {\beta _p} = (A/\alpha ) {t^{ -\alpha }}[1 + D {t^x}] + B $$
for T > Tλ, and simultaneously to the same function with primed coefficients for T < Tλ.

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. (1).
    G. Ahlers, Phys. Rev. A8, 530 (1973).ADSGoogle Scholar
  2. (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
  3. R. B. Griffiths, Phys. Rev. Lett. 24, 1479 (1970);ADSCrossRefGoogle Scholar
  4. D. Jasnow and M. Wortis, Phys. Rev. 176, 739 (1968)ADSCrossRefGoogle Scholar
  5. E. Brezin, J. C. Guillou, and J. Zinn-Justin, Phys. Lett. 47A, 285 (1974).ADSGoogle Scholar
  6. (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

Authors and Affiliations

  • K. H. Mueller
    • 1
  • F. Pobell
    • 1
  • Guenter Ahlers
    • 2
  1. 1.Institut für Festkörperforschung KernforschungsanlageJülichW. Germany
  2. 2.Bell LaboratoriesMurray HillUSA

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