354 research outputs found
On the Representation Theory of Orthofermions and Orthosupersymmetric Realization of Parasupersymmetry and Fractional Supersymmetry
We construct a canonical irreducible representation for the orthofermion
algebra of arbitrary order, and show that every representation decomposes into
irreducible representations that are isomorphic to either the canonical
representation or the trivial representation. We use these results to show that
every orthosupersymmetric system of order has a parasupersymmetry of order
and a fractional supersymmetry of order .Comment: 13 pages, to appear in J. Phys. A: Math. Ge
Evidence of strong stabilizing effects on the evolution of boreoeutherian (Mammalia) dental proportions.
The dentition is an extremely important organ in mammals with variation in timing and sequence of eruption, crown morphology, and tooth size enabling a range of behavioral, dietary, and functional adaptations across the class. Within this suite of variable mammalian dental phenotypes, relative sizes of teeth reflect variation in the underlying genetic and developmental mechanisms. Two ratios of postcanine tooth lengths capture the relative size of premolars to molars (premolar-molar module, PMM), and among the three molars (molar module component, MMC), and are known to be heritable, independent of body size, and to vary significantly across primates. Here, we explore how these dental traits vary across mammals more broadly, focusing on terrestrial taxa in the clade of Boreoeutheria (Euarchontoglires and Laurasiatheria). We measured the postcanine teeth of N = 1,523 boreoeutherian mammals spanning six orders, 14 families, 36 genera, and 49 species to test hypotheses about associations between dental proportions and phylogenetic relatedness, diet, and life history in mammals. Boreoeutherian postcanine dental proportions sampled in this study carry conserved phylogenetic signal and are not associated with variation in diet. The incorporation of paleontological data provides further evidence that dental proportions may be slower to change than is dietary specialization. These results have implications for our understanding of dental variation and dietary adaptation in mammals
Statistical Origin of Pseudo-Hermitian Supersymmetry and Pseudo-Hermitian Fermions
We show that the metric operator for a pseudo-supersymmetric Hamiltonian that
has at least one negative real eigenvalue is necessarily indefinite. We
introduce pseudo-Hermitian fermion (phermion) and abnormal phermion algebras
and provide a pair of basic realizations of the algebra of N=2
pseudo-supersymmetric quantum mechanics in which pseudo-supersymmetry is
identified with either a boson-phermion or a boson-abnormal-phermion exchange
symmetry. We further establish the physical equivalence (non-equivalence) of
phermions (abnormal phermions) with ordinary fermions, describe the underlying
Lie algebras, and study multi-particle systems of abnormal phermions. The
latter provides a certain bosonization of multi-fermion systems.Comment: 20 pages, to appear in J.Phys.
The Quantum-Classical Correspondence in Polygonal Billiards
We show that wave functions in planar rational polygonal billiards (all
angles rationally related to Pi) can be expanded in a basis of quasi-stationary
and spatially regular states. Unlike the energy eigenstates, these states are
directly related to the classical invariant surfaces in the semiclassical
limit. This is illustrated for the barrier billiard. We expect that these
states are also present in integrable billiards with point scatterers or
magnetic flux lines.Comment: 8 pages, 9 figures (in reduced quality), to appear in PR
Pre-eruptive magmatic processes re-timed using a non-isothermal approach to magma chamber dynamics
Open Source PaperThis work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise
in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. The attached file is the published version of the article
Anomalous plasma acceleration in colliding high-power laser-produced plasmas
We developed an experimental platform for studying magnetic reconnection in
an external magnetic field with simultaneous measurements of plasma imaging,
flow velocity, and magnetic-field variation. Here, we investigate the
stagnation and acceleration in counter-streaming plasmas generated by
high-power laser beams. A plasma flow perpendicular to the initial flow
directions is measured with laser Thomson scattering. The flow is,
interestingly, accelerated toward the high-density region, which is opposite to
the direction of the acceleration by pressure gradients. This acceleration is
possibly interpreted by the interaction of two magnetic field loops initially
generated by Biermann battery effect, resulting in a magnetic reconnection
forming a single field loop and additional acceleration by a magnetic tension
force.Comment: 6 pages, 4 figures, Physics of Plasmas, in pres
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