Abstract:
Two features of the diagram technique for Hubbard operators are
established, namely, the need to choose a definite way to
disentangle nondiagonal operators from a time-ordered product and
linear dependence of the concentration fluctuations on the
temperature.
Citation:
A. V. Vedyaev, M. Yu. Nikolaev, “Aspects of the diagram technique for Hubbard operators”, TMF, 59:2 (1984), 293–296; Theoret. and Math. Phys., 59:2 (1984), 510–512