Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Generalized Random Phase Approximation: Zero and Non-Zero Temperature
  Properties of an Interacting Electron Gas   Correlated systems at both zero and nonzero temperature are treated here from
a novel angle using a functional method. This functional method is an extension
of the usual effective potential method. Here, however the effective action is
made to depend explicitly on the correlation effects that are inherent in the
physics involved. This will enable us to obtain new expressions for the free
energy, the specific heat and the ground state energy. The new expansion is
shown to give the expected results for the homogeneous case at zero
temperature. However at non-zero temperature we are able to get new sets of
diagrams that have a vanishing effect at zero temperature. To lowest order
these diagrams if summed properly will solve a ln T anomaly in the specific
heat of an electron gas at low temperature. We are also able to show that this
method provides a very clear way to extend the RPA approximation. We calculate
the effect of exchange on the ring diagrams at zero temperature and show how to
include some of the ladder digrams. Our results agree well with known numerical
calculations. We conclude by showing that this method is in fact a variant of
the time dependent density functional method and can in principle be applied to
study the effects of correlation in the nonhomogeneous case.

1
The categories of this paper are: cs
10
The categories of this paper are: q-bio
19
The categories of this paper are: eess
30
The categories of this paper are: q-alg
2
The categories of this paper are: math
5
The categories of this paper are: gr-qc
28
The categories of this paper are: alg-geom
36
The categories of this paper are: cmp-lg
3
The categories of this paper are: physics
8
The categories of this paper are: hep-ex
20
The categories of this paper are: acc-phys
24
The categories of this paper are: dg-ga
16
The categories of this paper are: stat
27
The categories of this paper are: comp-gas
32
The categories of this paper are: atom-ph
12
The categories of this paper are: nucl-th