Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ultrasonic elastic responses in monopole lattice   The latest experimental advances have extended the scenario of coupling
mechanical degrees of freedom in chiral magnets (MnSi/MnGe) to the
topologically nontrivial skyrmion crystal and even monopole lattices. Equipped
with a spin-wave theory highlighting the topological features, we devise an
interacting model for acoustic phonons and magnons to explain the experimental
findings in a monopole lattice with a topological phase transition, i.e.,
annihilation of monopole-antimonopole pairs. We reproduce the anisotropic
magnetoelastic modulations of elastic moduli: drastic ultrasonic softening
around the phase transition and a multi-peak-and-trench fine structure for
sound waves parallel and orthogonal to the magnetic field, respectively.
Comparison with experiments indicates that the magnetoelastic coupling induced
by Dzyaloshinskii-Moriya interaction is comparable to that induced by the
exchange interaction. Other possibilities such as elastic hardening are also
predicted. The study implies that the monopole defects and their motion in MnGe
play a crucial role.

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The categories of this paper are: hep-ph
19
The categories of this paper are: eess
14
The categories of this paper are: math-ph
7
The categories of this paper are: hep-th
11
The categories of this paper are: hep-lat
5
The categories of this paper are: gr-qc
12
The categories of this paper are: nucl-th
20
The categories of this paper are: acc-phys
8
The categories of this paper are: hep-ex
1
The categories of this paper are: cs
15
The categories of this paper are: nucl-ex
29
The categories of this paper are: funct-an
32
The categories of this paper are: atom-ph
2
The categories of this paper are: math
35
The categories of this paper are: mtrl-th
16
The categories of this paper are: stat