Nonextensive boson gas and specific heat of 4He superfluid

The temperature dependence of the heat capacity C-v of the boson gas is studied within the generalized quantum statistics. The generalized heat capacity (C-v)(q) is shown to increase strongly at all temperatures with increasing nonextensive parameter q. This (C-v)(q) behavior is used to reproduce the observed curve of C-v(T) of the liquid He-4(II) for the temperature range 1 K less than or equal to T less than or equal to 2.17 K with particular q Values. We obtain an almost linear T-dependence of parameter q which increases with increasing temperature from q approximate to 0.5 at 1 K to q approximate to 1.35 at 2.17K. The observed He-4(I) -(4) He(II) transition temperature (2.17K) is also reproduced with q approximate to 1.36. (C) 2000 Elsevier Science B.V. All rights reserved.