Recent progress in statistical mechanics indicates the Tsallis non-extensiv
e thermostatistics as the natural generalization of the standard classical
and quantum statistics, when memory effects and long-range forces are not n
egligible. In this framework, we show that in weakly non-ideal plasma non-e
xtensive and quantum uncertainty effects should be taken into account to de
rive the equilibrium distribution functions, quantum fluctuations and corre
lations between the particles. The strong influence of these effects is dis
cussed in the context of the solar neutrino problem and in the high-energy
nuclear-nuclear collision experiments. Although the deviation from the Bolt
zmann-Gibbs statistics, in both cases, is very small, the nuclear reaction
rates and quantum fluctuations are strongly influenced by the non-extensive
feature of the solar plasma and the hadronic gas produced by a quark-gluon
plasma. The discrepancies between the experimental data and theoretical pr
evisions are sensibly reduced. (C) 2001 Elsevier Science Ltd. All rights re
served.