Measurements of the Complex Permittivity of Liquid Helium-4 in the Millimeter Wave Range by a Whispering Gallery Mode Resonator
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We report an experimental study of the electrical properties of liquid helium-4 in the temperature range 1.2–3 K. The experiment is carried out in the millimeter wave range using a whispering gallery mode dielectric resonator, and the complex permittivity of liquid helium is extracted from the data using the resonant perturbation method. The results for the temperature dependence of the dielectric constant are consistent with the previous studies. In addition, we find strong enhancement of the loss tangent around the superfluid transition temperature.
KeywordsDielectric constant and loss tangent of liquid helium Millimeter waves Whispering gallery mode resonator
The work was supported by an internal Grant from the Okinawa Institute of Science and Technology (OIST) Graduate University. A.S.R. was supported as a visiting researcher by the Okinawa Institute of Science and Technology (OIST) Graduate University.
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