Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Itinerant ferromagnetism in narrow-band metals   Since its introduction in 1963, the Hubbard model has becomes one of the most
popular models used in the literature to study cooperative phenomena in
narrow-band metals (ferromagnetism, metal-insulator transitions, charge-density
waves, high-T$_c$ superconductivity). Amongst all these cooperative phenomena,
the problem of itinerant ferromagnetism in the Hubbard model has the longest
history. However, in spite of an impressive research activity in the past, the
underlying physics (microscopic mechanisms) that leads to the stabilization of
itinerant ferromagnetism in Hubbard model (narrow-band metals) is still far
from being understood. In this review we present our numerical results
concerning this subject, which have been reached by small cluster exact
diagonalization, density matrix renormalization group and quantum Monte Carlo
calculations within various extensions of the Hubbard model. Particular
attention is paid to a description of crucial mechanisms (interactions) that
support the stabilization of the ferromagnetic state, and namely: (i) the
long-range hopping, (ii) the correlated hopping, (iii) the long-range Coulomb
interaction, (iv) the flat bands and (v) the lattice structure. Most of the
presented results have been obtained for the one-dimensional case, but the
influence of the increasing dimension of the system on the ferromagnetic state
is also intensively discussed.

26
The categories of this paper are: bayes-an
29
The categories of this paper are: funct-an
7
The categories of this paper are: hep-th
35
The categories of this paper are: mtrl-th
3
The categories of this paper are: physics
31
The categories of this paper are: ao-sci
21
The categories of this paper are: adap-org
11
The categories of this paper are: hep-lat
19
The categories of this paper are: eess
2
The categories of this paper are: math
12
The categories of this paper are: nucl-th
13
The categories of this paper are: quant-ph
9
The categories of this paper are: nlin
5
The categories of this paper are: gr-qc
18
The categories of this paper are: econ
6
The categories of this paper are: astro-ph