Comments on Coupling between pressure and temperature amplitude in waves of second sound in liquid helium

1971 ◽  
Vol 247 (4) ◽  
pp. 380-382
Author(s):  
I. Rudnick
Keyword(s):  
Liquid Helium ◽  
Second Sound ◽  
Temperature Amplitude

Quantum hydrodynamics and the theory of liquid helium

1953 ◽  
Vol 219 (1137) ◽  
pp. 257-270 ◽  
Keyword(s):  
Energy Spectrum ◽  
Liquid Helium ◽  
Fluid Velocity ◽  
Second Sound ◽  
Quantum Hydrodynamics ◽  
Dynamical Equations ◽  
Helium Ii ◽  
Apparent Variation ◽  
Theory Of Fields ◽  
Good Agreement

The Clebsch formula, u = –∇ ϕ – χ ∇ ψ , for the fluid velocity allows the classical hydro-dynamical equations, including vorticity, to be derived from a variational principle, and put into canonical form. The standard quantization procedure of the theory of fields then gives a set of field operators satisfying the commutation relations obtained (starting from different premises) by Landau (1941). The Hamiltonian contains terms corresponding to the excitation of the ‘roton’ states of Landau’s theory, with an energy spectrum (allowing for the atomicity of real liquids by a ‘cut off’ in the Fourier analysis of the field variables) of the form E = ∆ + p 2 /2 μ . The observed variations of specific heat and second-sound velocity in liquid helium II may be interpreted to give values of ∆ in good agreement with the theory, with an apparent variation of μ with p , perhaps attributable to roton-roton and phonon-roton interactions.

Second Sound Attenuation in Liquid Helium II

1954 ◽  
Vol 95 (2) ◽  
pp. 321-327 ◽  
Author(s):  
W. B. Hanson ◽  
J. R. Pellam
Keyword(s):  
Liquid Helium ◽  
Sound Attenuation ◽  
Second Sound ◽  
Helium Ii

Pulsed Second Sound in Liquid Helium II

1948 ◽  
Vol 74 (7) ◽  
pp. 841-841 ◽  
Author(s):  
J. R. Pellam
Keyword(s):  
Liquid Helium ◽  
Second Sound ◽  
Helium Ii

Second Sound Velocity in Paramagnetically Cooled Liquid Helium II

1949 ◽  
Vol 76 (6) ◽  
pp. 869-870 ◽  
Author(s):  
John R. Pellam ◽  
Russell B. Scott
Keyword(s):  
Sound Velocity ◽  
Liquid Helium ◽  
Second Sound ◽  
Helium Ii
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