Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: First-principles theory of magnetic multipoles in condensed matter
  systems   The multipole concept, which characterizes the spacial distribution of scalar
and vector objects by their angular dependence, has already become widely used
in various areas of physics. In recent years it has become employed to
systematically classify the anisotropic distribution of electrons and
magnetization around atoms in solid state materials. This has been fuelled by
the discovery of several physical phenomena that exhibit unusual higher rank
multipole moments, beyond that of the conventional degrees of freedom as charge
and magnetic dipole moment. Moreover, the higher rank electric/magnetic
multipole moments have been suggested as promising order parameters in exotic
hidden order phases. While the experimental investigations of such anomalous
phases have provided encouraging observations of multipolar order, theoretical
approaches have developed at a slower pace. In particular, a materials'
specific theory has been missing. The multipole concept has furthermore been
recognized as the key quantity which characterizes the resultant configuration
of magnetic moments in a cluster of atomic moments. This cluster multipole
moment has then been introduced as macroscopic order parameter for a
noncollinear antiferromagnetic structure in crystals that can explain unusual
physical phenomena whose appearance is determined by the magnetic point group
symmetry. It is the purpose of this review to discuss the recent developments
in the first-principles theory investigating multipolar degrees of freedom in
condensed matter systems. These recent developments exemplify that ab initio
electronic structure calculations can unveil detailed insight in the mechanism
of physical phenomena caused by the unconventional, multipole degree of
freedom.

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The categories of this paper are: hep-ex
37
The categories of this paper are: supr-con
16
The categories of this paper are: stat
25
The categories of this paper are: patt-sol
23
The categories of this paper are: solv-int
32
The categories of this paper are: atom-ph
26
The categories of this paper are: bayes-an
6
The categories of this paper are: astro-ph
12
The categories of this paper are: nucl-th
21
The categories of this paper are: adap-org
30
The categories of this paper are: q-alg
18
The categories of this paper are: econ
33
The categories of this paper are: plasm-ph
15
The categories of this paper are: nucl-ex
1
The categories of this paper are: cs
36
The categories of this paper are: cmp-lg