Molar volume of superfluid3He−4Hemixtures: The dependence of the Bardeen-Baym-Pines parameter on temperature, pressure, and

Abstract

We have developed a new method for determining the Bardeen-Baym-Pines ͑BBP͒ parameter of a superfluid 3 He-4 He mixture from the measurement of its molar volume within the wide ranges of temperature, pressure, and the 3 He concentration. The method and the results are described. The ranges of the present investigation are 0.4 -660 mK in temperature, 0.3-10 kgf/cm 2 in pressure, and 0.07-0.39 in the 3 He concentration. The data obtained are fitted with a formula based on the phenomenological theory of dilute solutions of 3 He in superfluid 4 He. Our empirical formula can reproduce the experimental values of the BBP parameter within the accuracy of 1%. The argument on the absolute uncertainty is also given.

Effective3He interactions in dilute3He-4He mixtures

“…The various parameters are defined through Eqs. (13) and (14). The pressure factors are in units 1/(25 bar).…”

Effective field theory of boson-fermion mixtures and bound fermion states on a vortex of boson superfluid

“…The BBP parameter at zero concentration α0(P ) is determined up to 10 atm by the experiment in Ref. [29]. α0(P ) for 15, 20 atm (indicated with daggers) are read from Ref.…”

THERMODYNAMIC PROPERTIES OF LIQUID [sup 3]He-[sup 4]He MIXTURES BETWEEN 0.15 K AND 1.5 K

“…The only extensive sources of molar volume data that we could find were by Kierstead [18] and by Hatakeyama et al [19]. The former presents molar volumes over the entire concentration range between 0.6 K and 1.8 K at saturated pressure; the latter present molar volumes in the He-II region below 0.66 K, from 0.3 bar-9.8 bar.…”

“…The slope of the dilute-phase surface ∂x d /∂p is calculated from the known dilute-phase-surface equation. At a given pressure, ∂v/∂x is calculated from Hatakeyama et al [19]. ∂ 2 g/∂x 2 is harder; it is known at zero pressure, but not at higher pressures.…”

“…The deviation term is calculated by fitting a functional form to values of v r , ∂v r /∂T and ∂v r /∂x calculated from Kierstead [18] and Hatakeyama et al [19]. (Accurate values of ∂v/∂T and ∂v/∂x are necessary for reliable calculations of s and µ 4 respectively.)…”