Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Electromagnetic Interactions of Electrons in the Lowest Landau Level   Starting from a system of planar electrons in a strong magnetic field normal
to the plane, interacting with perturbing electromagnetic fields, an effective
Lagrangian for the fermions in the lowest Landau level (L.L.L.) has been
derived. By choosing a suitable background electrostatic potential, an
incompressible droplet of these electrons is constructed. The gauge invariant
effective Lagrangian for the electrons in the L.L.L. is shown to split
naturally into a $1+1$ dimensional Lagrangian for the electrons on the surface
of the droplet and into a $2+1$ dimensional gauge-field Lagrangian representing
the contribution of the interior of the droplet. Upon bosonization, the former
represents the surface vibrations of the droplet. Individually neither of these
two actions is gauge invariant, but it is shown that the gauge dependence from
the two pieces cancels out. This demonstrates that the edge degrees of freedom
are essential for maintaining gauge invariance.

21
The categories of this paper are: adap-org
14
The categories of this paper are: math-ph
2
The categories of this paper are: math
24
The categories of this paper are: dg-ga
10
The categories of this paper are: q-bio
22
The categories of this paper are: chao-dyn
13
The categories of this paper are: quant-ph
6
The categories of this paper are: astro-ph
35
The categories of this paper are: mtrl-th
31
The categories of this paper are: ao-sci
29
The categories of this paper are: funct-an
1
The categories of this paper are: cs
34
The categories of this paper are: chem-ph
27
The categories of this paper are: comp-gas
23
The categories of this paper are: solv-int
3
The categories of this paper are: physics