LOW-TEMPERATURE ASYMPTOTIC BEHAVIOUR OF THE IMPURITY EFFECTIVE MASS IN SURERFLUID ⁴He

I. O. Vakarchuk, V. V. Babin
Ivan Franko National University of Lviv
12 Drahomanov Str., Lviv, UA-79005, Ukraine

The effective impurity Hamiltonian is built using the full statistic operator of the ``superfluid $^4$He + $^3$He--impurity" system which is averaged over liquid $^4$He states. The eigenvalues of this Hamiltonian are treated as the impurity spectrum at $T\neq 0$. The effective mass of the impurity atom is calculated in a ``one sum over wave vector" approximation. The low--temperature asymptotic behaviour of the effective mass is considered.

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