A Kosterlitz-Thouless transition in solid $4^$ Helium?

ORAL

Abstract

We show that the reproducible ``Non-Classical Rotational Inertia'' signals in solid Helium four are completely ascribable to a Kosterlitz-Thouless transition of liquid $^4$He at the grain boundaries. Despite our toy model, we obtain a surprisingly good agreement with the experimental data when comparing the drop of the momentum of inertia. Within our model, we give an estimate of the average size of the grains, which we argue to be limited by the isotopic impurities and show that the signal is inversely proportional to the size of the average size of the grains.

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Authors

  • Sergio Gaudio

    • University of Rome La Sapienza
    • Dipartimento di Fisica, Universita' di Roma, La Sapienza

  • Emmanuele Cappeluti

    • Dipartimento di Fisica, Universita' di Roma, La Sapienza and ISC, INFM-CNR, Roma Italy

  • Gianluca Rastelli

    • Universite' Joseph Fourier, Grenoble, France

  • Luciano Pietronero

    • Dipartimento di Fisica, Universita' di Roma, La Sapienza and SMC Research Center and ISC, INFM-CNR, Roma Italy