Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Non-exponential relaxation and quantum tunnel splitting in molecular
  magnet Fe8   Magnetic relaxation in molecular magnets under a sweeping field is studied by
taking into account local stray fields. It is found that the randomness of
local stray field leads to a distribution of the relaxation rate which
subsequently makes the relaxation deviate from the exponential law as predicted
by the Landau-Zener model such that the Landau-Zener method needs to be revised
to deduce an exact tunneling splitting. The tunneling splitting and
distribution width of local stray fields are derived from the experimental data
for molecular magnets Fe8.

12
The categories of this paper are: nucl-th
17
The categories of this paper are: q-fin
16
The categories of this paper are: stat
26
The categories of this paper are: bayes-an
11
The categories of this paper are: hep-lat
25
The categories of this paper are: patt-sol
5
The categories of this paper are: gr-qc
21
The categories of this paper are: adap-org
22
The categories of this paper are: chao-dyn
32
The categories of this paper are: atom-ph
24
The categories of this paper are: dg-ga
8
The categories of this paper are: hep-ex
9
The categories of this paper are: nlin
34
The categories of this paper are: chem-ph
28
The categories of this paper are: alg-geom
19
The categories of this paper are: eess