Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Valence transition in the periodic Anderson model   A very rich phase diagram has recently been found in CeCu$_{2}$Si$_{2}$ from
high pressure experiments where, in particular, a transition between an
intermediate valence configuration and an integral valent heavy fermion state
has been observed. We show that such a valence transition can be understood in
the framework of the periodic Anderson model. In particular, our results show a
breakdown of a mixed-valence state which is accompanied by a drastic change in
the \textit{f} occupation in agreement with experiment. This valence transition
can possibly be interpreted as a collapse of the large Fermi surface of the
heavy fermion state which incorporates not only the conduction electrons but
also the localized \textit{f} electrons. The theoretical approach used in this
paper is based on the novel projector-based renormalization method (PRM). With
respect to the periodic Anderson model, the method was before only employed in
combination with the basic approximations of the well-known slave-boson
mean-field theory. In this paper, the PRM treatment is performed in a more
sophisticated manner where both mixed as well as integral valent solutions have
been obtained. Furthermore, we argue that the presented PRM approach might be a
promising starting point to study the competing interactions in
CeCu$_{2}$Si$_{2}$ and related compounds.

27
The categories of this paper are: comp-gas
26
The categories of this paper are: bayes-an
9
The categories of this paper are: nlin
37
The categories of this paper are: supr-con
6
The categories of this paper are: astro-ph
7
The categories of this paper are: hep-th
14
The categories of this paper are: math-ph
12
The categories of this paper are: nucl-th
11
The categories of this paper are: hep-lat
18
The categories of this paper are: econ
5
The categories of this paper are: gr-qc
3
The categories of this paper are: physics
22
The categories of this paper are: chao-dyn
2
The categories of this paper are: math
21
The categories of this paper are: adap-org
8
The categories of this paper are: hep-ex