Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Magnetic vortex dynamics in a 2D easy plane ferromagnet   In this thesis, we consider the dynamics of vortices in the easy plane
insulating ferromagnet in two dimensions. In addition to the quasiparticle
excitations, here spin waves or magnons, this magnetic system admits a family
of vortex solutions carrying two topological invariants, the winding number or
vorticity, and the polarization. A vortex is approximately described as a
particle moving about the system, endowed with an effective mass and acted upon
by a variety of forces. Classically, the vortex has an inter-vortex potential
energy giving a Coulomb-like force (attractive or repulsive depending on the
relative vortex vorticity), and a gyrotropic force, behaving as a self-induced
Lorentz force, whose direction depends on both topological indices. Expanding
semiclassically about a many-vortex solution, the vortices are quantized by
considering the scattered magnon states, giving a zero point energy correction
and a many-vortex mass tensor. The vortices cannot be described as independent
particles--that is, there are off-diagonal mass terms, such as 1/2 Mij vi vj,
that are non-negligible. This thesis examines the full vortex dynamics in
further detail by evaluating the Feynman-Vernon influence functional, which
describes the evolution of the vortex density matrix after the magnon modes
have been traced out. In addition to the set of forces already known, we find
new damping forces acting both longitudinally and transversely to the vortex
motion. The vortex motion within a collective cannot be entirely separated:
there are damping forces acting on one vortex due to the motion of another. The
effective damping forces have memory effects: they depend not only on the
current motion of the vortex collection but also on the motion history.

12
The categories of this paper are: nucl-th
27
The categories of this paper are: comp-gas
22
The categories of this paper are: chao-dyn
19
The categories of this paper are: eess
15
The categories of this paper are: nucl-ex
13
The categories of this paper are: quant-ph
5
The categories of this paper are: gr-qc
0
The categories of this paper are: hep-ph
18
The categories of this paper are: econ
3
The categories of this paper are: physics
28
The categories of this paper are: alg-geom
20
The categories of this paper are: acc-phys
24
The categories of this paper are: dg-ga
11
The categories of this paper are: hep-lat
35
The categories of this paper are: mtrl-th
7
The categories of this paper are: hep-th