Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Electron fractionalization for two-dimensional Dirac fermions   Fermion-number fractionalization without breaking of time-reversal symmetry
was recently demonstrated for a field theory in $(2+1)$-dimensional space and
time that describes the couplings between massive Dirac fermions, a
complex-valued Higgs field carrying an axial gauge charge of 2, and a U(1)
axial gauge field. Charge fractionalization occurs whenever the Higgs field
either supports vortices by itself, or when these vortices are accompanied by
half-vortices in the axial gauge field. The fractional charge is computed by
three different techniques. A formula for the fractional charge is given as a
function of a parameter in the Dirac Hamiltonian that breaks the spectral
energy-reflection symmetry. In the presence of a charge $\pm1$ vortex in the
Higgs field only, the fractional charge varies continuously and thus can take
irrational values. The simultaneous presence of a half-vortex in the axial
gauge field and a charge $\pm1$ vortex in the Higgs field re-rationalizes the
fractional charge to the value 1/2.

10
The categories of this paper are: q-bio
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The categories of this paper are: math-ph
36
The categories of this paper are: cmp-lg
34
The categories of this paper are: chem-ph
17
The categories of this paper are: q-fin
27
The categories of this paper are: comp-gas
37
The categories of this paper are: supr-con
32
The categories of this paper are: atom-ph
26
The categories of this paper are: bayes-an
35
The categories of this paper are: mtrl-th
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The categories of this paper are: alg-geom
5
The categories of this paper are: gr-qc
29
The categories of this paper are: funct-an
0
The categories of this paper are: hep-ph
33
The categories of this paper are: plasm-ph
24
The categories of this paper are: dg-ga