Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Role of thermal vibrations in magnetic phase transitions   We address and resolve the fundamental contradiction that has existed from
the earliest studies on magnetic phase transitions between theoretical models
that ignore the role of thermal vibrations and represent the exchange
interaction as a constant, Jij(0), and analysis of neutron diffraction data
that always incorporates thermal vibrations even though it is also possible to
analyze the same data by ignoring them. Of the two possibilities, ignoring
thermal vibrations in both theoretical models and analysis of diffraction data
leads to the latter giving different magnetic order parameters for different
reciprocal lattice lines. This appears to be the first report of a unique
consequence, viz. the assumption to neglect a physical phenomenon turns a
single-valued experimental observable into a multiple-valued one where all
values are equally valid. This assumption is clearly unacceptable and must be
rejected. The second possibility of incorporating thermal vibrations in both
leads to single-valued theoretical and experimental order parameters. Thus,
analysis of neutron diffraction data constrain the exchange interaction in all
theoretical models to be temperature dependent and represented as Jij(T).
Additional experimental and theoretical evidences in support of this conclusion
are presented.

10
The categories of this paper are: q-bio
17
The categories of this paper are: q-fin
9
The categories of this paper are: nlin
27
The categories of this paper are: comp-gas
22
The categories of this paper are: chao-dyn
37
The categories of this paper are: supr-con
20
The categories of this paper are: acc-phys
8
The categories of this paper are: hep-ex
2
The categories of this paper are: math
23
The categories of this paper are: solv-int
16
The categories of this paper are: stat
19
The categories of this paper are: eess
32
The categories of this paper are: atom-ph
15
The categories of this paper are: nucl-ex
21
The categories of this paper are: adap-org
24
The categories of this paper are: dg-ga