Energy spectrum, normal-fluid density, and specific heat of3He quasiparticles in dilute3He-He II mixtures

1982 ◽  
Vol 49 (1-2) ◽  
pp. 135-149 ◽  
Author(s):  
A. Szprynger
Keyword(s):  
Energy Spectrum ◽  
Specific Heat ◽  
Fluid Density ◽  
Normal Fluid

Thermodynamic Properties of an In-Phase Flux Antiferromagnetic Spin Coupled Heisenberg Model on a Square Lattice

SPIN ◽  
2018 ◽  
Vol 08 (04) ◽  
pp. 1830001
Author(s):  
E. Mainimo ◽  
N. Ibrahim Famenyi
Keyword(s):  
Energy Spectrum ◽  
Specific Heat ◽  
Thermodynamic Parameters ◽  
Heisenberg Model ◽  
State Energy ◽  
Spontaneous Magnetization ◽  
Exchange Interactions ◽  
Spin Model ◽  
Square Lattice ◽  
Antiferromagnetic Spin

Using the two-dimensional Jordan–Wigner Fermionization procedure, we calculate the energy spectrum of the in-phase flux antiferromagnetically spin-1/2 coupled Heisenberg model in a square lattice, the formalism used introduces the notion of isotropic parameters. The energy spectrum is analyzed for various regimes of the exchange interactions and the isotropic parameters. The thermodynamic parameters of the lattice, notably the ground state energy, the free energy, mean energy, entropy and specific heat are calculated. It is seen that the specific heat undergoes a phase transition at a temperature below the critical temperature due to spontaneous magnetization. Its entropy for homogeneous and completely isotropic regime is compared for two regimes of the exchange interaction and it is observed that the entropy decreases with an increase in the coupling strength. All the thermodynamic parameters calculated for this spin model are seen to be in conformity with the principles and laws of Statistical Thermodynamics.

Normal Fluid Density of LiquidHe3-B

1979 ◽  
Vol 43 (2) ◽  
pp. 139-143 ◽  
Author(s):  
C. N. Archie ◽  
T. A. Alvesalo ◽  
J. D. Reppy ◽  
R. C. Richardson
Keyword(s):  
Fluid Density ◽  
Normal Fluid

Ultrasonic studies of liquid helium in porous media

1987 ◽  
Vol 65 (11) ◽  
pp. 1557-1559 ◽  
Author(s):  
J. R. Beamish ◽  
K. Warner
Keyword(s):  
Porous Media ◽  
Sound Propagation ◽  
Porous Ceramic ◽  
Ultrasonic Waves ◽  
Effective Density ◽  
Biot Theory ◽  
Fluid Density ◽  
Normal Fluid ◽  
Superfluid Fraction ◽  
Viscous Losses

We have studied the propagation of 12 MHz transverse ultrasonic waves in a porous ceramic containing liquid 4He. Both the sound velocity and the attenuation clearly show the superfluid nature of helium. The helium in the pores increases the system's effective density by an amount proportional to the normal-fluid density and so decreases the sound speed. The decoupling of the superfluid fraction below the lambda transition allows us to use the shear wave essentially as a "high-frequency torsional oscillator" to determine the superfluid density and pore tortuosity. The sound attenuation in this system is due to the same mechanism as for fourth sound, namely, viscous losses due to motion of the normal-fluid component. We observed an attenuation proportional to the normal-fluid density and compare this result to predictions of the Biot theory of sound propagation in fluid-filled porous media.

Normal fluid density of superfluid 3He-B

Nature ◽  
1979 ◽  
Vol 281 (5728) ◽  
pp. 179-180
Author(s):  
P.V.E. McClintock
Keyword(s):  
Superfluid 3He ◽  
Fluid Density ◽  
Normal Fluid

scholarly journals On the Effective Normal Fluid Density tf Solution of He3in He4

1957 ◽  
Vol 17 (1) ◽  
pp. 126-128
Author(s):  
S. K. Trikha ◽  
V. S. Nanda
Keyword(s):  
Fluid Density ◽  
Normal Fluid
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