arXiv subjects

Thomas Moran

Publications and source records attributed to Thomas Moran.

5 recordsLinked to original sources

arXiv2026

Tensor product degenerate spin affine Hecke superalgebras

We define a new class of superalgebras, called tensor product degenerate spin affine Hecke superalgebras, and study their structure theory. We establish an isomorphism that relates the tensor product degenerate spin affine Hecke superalgebras to the tensor product degenerate affine Hecke-Clifford superalgebras. The relationship between these superalgebras is a tensor product analogue of the relationship between the degenerate spin affine Hecke superalgebras and degenerate affine Hecke-Clifford superalgebras.

math.RT↗

arXiv2026

Higher-level affine wreath product algebras

We define and study two new classes of algebras, called higher-level affine wreath product algebras and higher-level affine Frobenius Hecke algebras. They depend on a Frobenius superalgebra and are defined, respectively, as path algebras of the higher-level affine wreath product category and higher-level affine Frobenius Hecke category. Our constructions produce a broad range of new higher-level algebras under a unified framework. Special cases include higher-level analogues of the degenerate affine Hecke algebra and affine Sergeev algebras, both of which appear to be new.

math.RT↗

arXiv2024

A generalization of the first Tits construction

Let $F$ be a field of characteristic not 2 or 3. The first Tits construction is a well-known tripling process to construct separable cubic Jordan algebras, especially Albert algebras. We generalize the first Tits construction by choosing the scalar employed in the tripling process outside of the base field. This yields a new family of nonassociative unital algebras which carry a cubic map, and maps that can be viewed as generalized adjoint and generalized trace maps. These maps display properties often similar to the ones in the classical setup. In particular, the cubic norm map permits some kind of weak Jordan composition law.

math.RA↗

arXiv2022

Defeating depolarizing fields with artificial flux closure in ultrathin ferroelectrics

Material surfaces encompass structural and chemical discontinuities that often lead to the loss of the property of interest in the so-called dead layers. It is notably problematic in nanoscale oxide electronics, where the integration of strongly correlated materials into devices is obstructed by the thickness threshold required for the emergence of their functionality. Here, we report the stabilization of ultrathin out-of-plane ferroelectricity in oxide heterostructures through the design of an artificial flux-closure architecture. Inserting an in-plane polarized ferroelectric epitaxial buffer provides continuity of polarization at the interface, and despite its insulating nature we observe the emergence of polarization in our out-of-plane-polarized model ferroelectric BaTiO$_{3}$ from the very first unit cell. In BiFeO$_{3}$, the flux-closure approach stabilizes a conceptually novel 251$^{\circ}$ domain wall. Its unusual chirality is likely associated with the ferroelectric analog to the Dzyaloshinskii-Moriya interaction. We thus see that in an adaptively engineered geometry, the depolarizing-field-screening properties of an insulator can even surpass those of a metal and be a source of new functionalities. This should be a useful insight on the road towards the next generation of ferroelectric-based oxide electronics.

cond-mat.mtrl-sci↗

arXiv2001

Solar Magnetic Field Studies Using the 12-Micron Emission Lines. IV. Observations of a Delta-Region Solar Flare

We have recently developed the capability to make solar vector (Stokes IQUV) magnetograms using the infrared line of MgI at 12.32 microns. On 24 April 2001, we obtained a vector magnetic map of solar active region NOAA 9433, fortuitously just prior to the occurrence of an M2 flare. Examination of a sequence of SOHO/MDI magnetograms, and comparison with ground-based H-alpha images, shows that the flare was produced by the cancellation of newly emergent magnetic flux outside of the main sunspot. The very high Zeeman-sensitivity of the 12-micron data allowed us to measure field strengths on a spatial scale which was not directly resolvable. At the flare trigger site, opposite polarity fields of 2700 and 1000 Gauss occurred within a single 2 arc-sec resolution element, as revealed by two resolved Zeeman splittings in a single spectrum. Our results imply an extremely high horizontal field strength gradient (5 G/km) prior to the flare, significantly greater than seen in previous studies. We also find that the magnetic energy of the cancelling fields was more than sufficient to account for the flare's X-ray luminosity.

astro-ph↗