Superfluid density in He II near the lambda transition: First principles theory

Autor: H.W. Jackson
Rok vydání: 2015
Předmět:
Zdroj: Physica B: Condensed Matter. 461:92-100
ISSN: 0921-4526
DOI: 10.1016/j.physb.2014.11.102
Popis: A first principles theory of the λ transition in liquid 4He was introduced in a recent paper [H. W. Jackson, J. Low Temp. Phys. 155, 1 (2009)]. In that theory critical fluctuations consisting of isothermal fourth sound waves are treated with quantum statistical mechanics methods in deriving formulas for constant volume conditions for specific heat, correlation length, equal time pair correlation function, and isothermal compressibility. To leading order terms in (Tλ−T) the theory yields exact results α′=0 and ν′=2/3 for critical exponents at constant volume. A follow-up study in the present paper demonstrates by a least squares fit that a logarithmic function accurately describes the specific heat at svp when (Tλ−T) is between 10−9 K and 10−5 K. This logarithmic divergent behavior conflicts with previous analyses of experimental data and predictions of renormalization group theory that constant pressure specific heat is finite at Tλ, but Is thermodynamically consistent with logarithmic asymptotic behavior of specific heat at constant volume predicted in the new theory. The first principles theory is extended in this paper to derive formulas for superfluid density and for a relation between superfluid density and correlation length in He II near Tλ. Numerical results based on these formulas are in good agreement with experimental data produced by second sound measurements.
Databáze: OpenAIRE
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