5,734 research outputs found
Skyrmions and Hall viscosity
We discuss the contribution of magnetic Skyrmions to the Hall viscosity and
propose a simple way to identify it in experiments. The topological Skyrmion
charge density has a distinct signature in the electric Hall conductivity that
is identified in existing experimental data. In an electrically neutral system,
the Skyrmion charge density is directly related to the thermal Hall
conductivity. These results are direct consequences of the field theory Ward
identities, which relate various physical quantities based on symmetries and
have been previously applied to quantum Hall systems.Comment: 10 pages, based on the invited talk at the 62nd Annual Conference on
Magnetism and Magnetic Materials (MMM conference), November 6-10, Pittsburgh,
P
Entanglement Entropy with Background Gauge Fields
We study the entanglement entropy, the R\'enyi entropy, and the mutual
(R\'enyi) information of Dirac fermions on a 2 dimensional torus in the
presence of constant gauge fields. We derive their general formulas using the
equivalence between twisted boundary conditions and the background gauge
fields. Novel and interesting physical consequences have been presented in
arXiv:1705.01859. Here we provide detailed computations of the entropies and
mutual information in a low temperature limit, a large radius limit, and a high
temperature limit. The high temperature limit reveals rather different physical
properties compared to those of the low temperature one: there exist two
non-trivial limits that depend on a modulus parameter and are not smoothly
connected.Comment: 37 pages, v2: some formulas in section 4.3 are correcte
KSBA compactification of the moduli space of K3 surfaces with purely non-symplectic automorphism of order four
We describe a compactification by KSBA stable pairs of the five-dimensional
moduli space of K3 surfaces with purely non-symplectic automorphism of order
four and lattice polarization. These K3 surfaces can
be realized as the minimal resolution of the double cover of
branched along a specific curve. We
show that, up to a finite group action, this stable pairs compactification is
isomorphic to Kirwan's partial desingularization of the GIT quotient
with the symmetric linearization.Comment: 26 pages, 6 figures. We explain the connection with Alexeev-Thompson
work on ADE surfaces. Comments are welcom
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