Exotic Construction Research Articles

Comparing elliptic and toric hypersurface Calabi-Yau threefolds at large Hodge numbers

We compare the sets of Calabi-Yau threefolds with large Hodge numbers that are constructed using toric hypersurface methods with those can be constructed as elliptic fibrations using Weierstrass model techniques motivated by F-theory. There is a close correspondence between the structure of “tops” in the toric polytope construction and Tate form tunings of Weierstrass models for elliptic fibrations. We find that all of the Hodge number pairs (h1,1, h2,1) with h1,1 or h2,1 ≥ 240 that are associated with threefolds in the Kreuzer-Skarke database can be realized explicitly by generic or tuned Weierstrass/Tate models for elliptic fibrations over complex base surfaces. This includes a relatively small number of somewhat exotic constructions, including elliptic fibrations over non-toric bases, models with new Tate tunings that can give rise to exotic matter in the 6D F-theory picture, tunings of gauge groups over non-toric curves, tunings with very large Hodge number shifts and associated nonabelian gauge groups, and tuned Mordell-Weil sections associated with U(1) factors in the corresponding 6D theory.

GLSM realizations of maps and intersections of Grassmannians and Pfaffians

In this paper we give gauged linear sigma model (GLSM) realizations of a number of geometries not previously presented in GLSMs. We begin by describing GLSM realizations of maps including Veronese and Segre embeddings, which can be applied to give GLSMs explicitly describing non-complete intersection constructions such as the intersection of one hypersurface with the image under some map of another. We also discuss GLSMs for intersections of Grassmannians and Pfaffians with one another, and with their images under various maps, which sometimes form exotic constructions of Calabi-Yaus, as well as GLSMs for other exotic Calabi-Yau constructions of Kanazawa. Much of this paper focuses on a specific set of examples of GLSMs for intersections of Grassmannians G(2, N ) with themselves after a linear rotation, including the Calabi-Yau case N = 5. One phase of the GLSM realizes an intersection of two Grassmannians, the other phase realizes an intersection of two Pfaffians. The GLSM has two nonabelian factors in its gauge group, and we consider dualities in those factors. In both the original GLSM and a double-dual, one geometric phase is realized perturbatively (as the critical locus of a superpotential), and the other via quantum effects. Dualizing on a single gauge group factor yields a model in which each geometry is realized through a simultaneous combination of perturbative and quantum effects.

Autoexoticism with Promotional Purposes? Samuel-Henri Berthoud and Provincial Literary Ruse in Nineteenth-Century France

“There speaks the provincial!”—Goncharov, The Same Old StoryIn nineteenth-century france, the so-called province, denoting everything outside Paris, was considered a foreign land by Parisian writers, who often constructed it as an exotic space. When we deal with this kind of provincial exoticism, however, considering this perspective alone risks painting an incomplete picture of the French literary field. Through the example of Samuel-Henri Berthoud, an author from the north of France, my intention here is to shed light on autoexoticist practices by indigenous provincial writers and to explore how they actively reclaimed, fostered, and enhanced exotic constructions about their provinces. Indeed, a wealth of evidence supports my argument that their acceptance of hegemonic constructions from the dominant culture was not passive but rather an active and creative reappropriation. This essay also challenges the idea of a stable hegemonic cultural center around which the marginal authors and literary works gravitate. Before tackling these issues, let us take a step back and briefly survey the particular value of provincial France at the beginning of the nineteenth century.

An ion analyzer for the lunar surface with E-parallel–B

We present a novel instrument concept to measure the energy and mass spectra of ions incident on the lunar surface, based on the E-parallel–B or Thomson-parabola device used extensively as a diagnostic in the plasma fusion community. The Apollo-era Suprathermal Ion Detector Experiment (SIDE) was the first instrument package to perform in-situ measurements of ions incident on the lunar surface. The ions can originate from a variety of sources, including the solar wind, the Earth’s magnetotail, and photoionization of the thin lunar atmosphere. The species and energy distribution of ions arriving at the lunar surface depend in a complicated and poorly-understood fashion on the phase of the lunar day, the position of the Moon with respect to the Earth, and on the local plasma environment.The SIDE instrument used a stepped electrostatic mass analyzer in combination with a stepped crossed-field (Wien) velocity filter to analyze incoming ions. The stepped mode of operation limited both the resolution of the device (6 energy steps, 20 velocity steps, in conjunction with a 20-step dedicated energy analyzer) and the temporal resolution (2.6min for a full energy-velocity scan).A modern diagnostic tool with significant heritage in the plasma fusion community is the E-parallel–B analyzer. This instrument is capable of analyzing the charge-to-mass ratio and momentum of individual particles. Each ion passing through a region with parallel E and B fields is deflected to a unique location on a 2D target according to its energy and mass. Energy and mass spectra can then be recorded using a 2D sensing technique; for example, a microchannel plate backed by a cross-delay-line (XDL) readout. The E-parallel–B design has the additional advantage of being physically compact and requiring modest field magnitudes, with electric fields on the order of a few kV/m and magnetic fields of tens to hundreds of Gauss, neither of which require exotic construction or heavy components.