The ground state energy, the excitation spectra and the structure factors of weakly coupled mixtures of charged particles (bosons or fermions) are obtained in the well-known framework of the Feynman diagrams. The general theory, which is developed in a first part, is then applied to the three...

Excitation spectra and thermodynamic properties of a weakly coupled mixture of two Bose fluids at zero temperature are obtained by making the appropriate Bogoliubov transforamtion. The main part of the work is concerned with purely coulombic interactions, but the non-coulombic case is also...

We show by an effective calculation of the entropy that negative temperatures do not exist in two-dimensional inviscid fluids or guiding center plasmas. The entropy is always a non-decreasing function of the energy. Its exact form depends on the behaviour of the interaction potential at large...

As in the three-dimensional case, we show, from the BBGKY hierarchy and under exponential clustering assumption, that the two-dimensional one-component plasma obeys the compressibility sum rule which links the compressibility to the fourth moment of the two-point correlation function. A new sum...