107 research outputs found
The First Cohomology of Lie Superalgebra with Coefficients in Kac Modules
Over a field of characteristic p>2, firstly, the structure of Kac modules of
Lie superalgebra and the weight space decompositions are given.
Secondly, the weight-derivations of to its Kac modules are
computed. Finally, the first cohomology of with coefficients in
Kac modules is determined
Dimension Reduction for Positively Curved Steady Solitons
We consider noncollapsed steady gradient Ricci solitons with nonnegative
sectional curvature. We show that such solitons always dimension reduce at
infinity. This generalizes an earlier result in [CDM22] to higher dimensions.
In dimension four, we classify possible reductions at infinity, which lays
foundation for possible classifications of steady solitons. Moreover, we show
that any tangent flow at infinity of a general noncollapsed steady soliton must
split off a line. This generalizes an earlier result in [BCDMZ21] to higher
dimensions. While this article is under preparation, we realized that part of
our main results are proved independently in a recent post [ZZ23] under
different assumptions
Tuning the Dzyaloshinskii-Moriya Interaction in Pt/Co/MgO heterostructures through MgO thickness
The interfacial Dzyaloshinskii-Moriya interaction (DMI) in the
ferromagnetic/heavy metal ultra-thin film structures , has attracted a lot of
attention thanks to its capability to stabilize Neel-type domain walls (DWs)
and magnetic skyrmions for the realization of non-volatile memory and logic
devices. In this study, we demonstrate that magnetic properties in
perpendicularly magnetized Ta/Pt/Co/MgO/Pt heterostructures, such as
magnetization and DMI, can be significantly influenced through both the MgO and
the Co ultrathin film thickness. By using a field-driven creep regime domain
expansion technique, we find that non-monotonic tendencies of DMI field appear
when changing the thickness of MgO and the MgO thickness corresponding to the
largest DMI field varies as a function of the Co thicknesses. We interpret this
efficient control of DMI as subtle changes of both Pt/Co and Co/MgO interfaces,
which provide a method to investigate ultra-thin structures design to achieve
skyrmion electronics.Comment: 18 pages, 11 figure
Local smooth convergence of -limit flows
The metric flow is introduced and extensively studied by Bamler [Bam20b,
Bam20c], especially as an -limit of a sequence of smooth Ricci
flows with uniformly bounded Nash entropy, in which case each regular point on
the limit is a point of smooth convergence. In this note, we shall consider the
-convergence of a sequence of -limit flows, and, like
Bamler, show that each regular point on the limit is also a point of smooth
convergence. The main result will be applied in a forthcoming work of the
authors [CMZ23]
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