1,304 research outputs found
Mining the Milky Way: How to Bring America’s Extraterrestrial Excursions Back Into Compliance With International Obligations
In November of 2015, the 114th United States Congress enacted the Commercial Space Launch Competitiveness Act of 2015 (Space Act) and, in turn, thrusted the door to outer space mining wide open for Americans. Unfortunately, while the Space Act provided a solution for corporations, it created a di- lemma for the United States. As currently enacted, the Space Act directly conflicts with the world’s foundational and most basic framework for international space law: The Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, Including the Moon and Other Celestial Bodies (Outer Space Treaty). To reassure other signatories and to ensure the United States complies with its international obligations under the Outer Space Treaty, Congress should establish a centralized regulatory authority to govern the activities of American entities in outer space and amend the Space Act to require bonding and permit- ting processes for entities wishing to engage in asteroid mining. This Article is the first to analyze how to modify existing legislation to impose sufficient regulation so the United States may once again comply with its international obligations under Article VI of the Outer Space Treaty. This Article will show that given the inherent risks of outer space mining, the intent and origins of the Outer Space Treaty, and the conflicting allowances contained in the Space Act, changes must be enacted to ensure that the tradition of treaty compliance and mineral- extraction regulation does not stop at our planet’s troposphere
On Charge-3 Cyclic Monopoles
We determine the spectral curve of charge 3 BPS su(2) monopoles with C_3
cyclic symmetry. The symmetry means that the genus 4 spectral curve covers a
(Toda) spectral curve of genus 2. A well adapted homology basis is presented
enabling the theta functions and monopole data of the genus 4 curve to be given
in terms of genus 2 data. The Richelot correspondence, a generalization of the
arithmetic mean, is used to solve for this genus 2 curve. Results of other
approaches are compared.Comment: 34 pages, 16 figures. Revision: Abstract added and a few small
change
Phenomenology of a light scalar: the dilaton
We make use of the language of non-linear realizations to analyze
electro-weak symmetry breaking scenarios in which a light dilaton emerges from
the breaking of a nearly conformal strong dynamics, and compare the
phenomenology of the dilaton to that of the well motivated light composite
Higgs scenario. We argue that -- in addition to departures in the
decay/production rates into massless gauge bosons mediated by the conformal
anomaly -- characterizing features of the light dilaton scenario (as well as
other scenarios admitting a light CP-even scalar not directly related to the
breaking of the electro-weak symmetry) are off-shell events at high invariant
mass involving two longitudinally polarized vector bosons and a dilaton, and
tree-level flavor violating processes. Accommodating both electro-weak
precision measurements and flavor constraints appears especially challenging in
the ambiguous scenario in which the Higgs and the dilaton fields strongly mix.
We show that warped higgsless models of electro-weak symmetry breaking are
explicit and tractable realizations of this limiting case.
The relation between the naive radion profile often adopted in the study of
holographic realizations of the light dilaton scenario and the actual dynamical
dilaton field is clarified in the Appendix.Comment: 21 page
The hypertoric intersection cohomology ring
We present a functorial computation of the equivariant intersection
cohomology of a hypertoric variety, and endow it with a natural ring structure.
When the hyperplane arrangement associated with the hypertoric variety is
unimodular, we show that this ring structure is induced by a ring structure on
the equivariant intersection cohomology sheaf in the equivariant derived
category. The computation is given in terms of a localization functor which
takes equivariant sheaves on a sufficiently nice stratified space to sheaves on
a poset.Comment: Significant revisions in Section 5, with several corrected proof
Temperature Dependence of Interlayer Magnetoresistance in Anisotropic Layered Metals
Studies of interlayer transport in layered metals have generally made use of
zero temperature conductivity expressions to analyze angle-dependent
magnetoresistance oscillations (AMRO). However, recent high temperature AMRO
experiments have been performed in a regime where the inclusion of finite
temperature effects may be required for a quantitative description of the
resistivity. We calculate the interlayer conductivity in a layered metal with
anisotropic Fermi surface properties allowing for finite temperature effects.
We find that resistance maxima are modified by thermal effects much more
strongly than resistance minima. We also use our expressions to calculate the
interlayer resistivity appropriate to recent AMRO experiments in an overdoped
cuprate which led to the conclusion that there is an anisotropic, linear in
temperature contribution to the scattering rate and find that this conclusion
is robust.Comment: 8 pages, 4 figure
The Curve of Compactified 6D Gauge Theories and Integrable Systems
We analyze the Seiberg-Witten curve of the six-dimensional N=(1,1) gauge
theory compactified on a torus to four dimensions. The effective theory in four
dimensions is a deformation of the N=2* theory. The curve is naturally
holomorphically embedding in a slanted four-torus--actually an abelian
surface--a set-up that is natural in Witten's M-theory construction of N=2
theories. We then show that the curve can be interpreted as the spectral curve
of an integrable system which generalizes the N-body elliptic Calogero-Moser
and Ruijsenaars-Schneider systems in that both the positions and momenta take
values in compact spaces. It turns out that the resulting system is not simply
doubly elliptic, rather the positions and momenta, as two-vectors, take values
in the ambient abelian surface. We analyze the two-body system in some detail.
The system we uncover provides a concrete realization of a Beauville-Mukai
system based on an abelian surface rather than a K3 surface.Comment: 22 pages, JHEP3, 4 figures, improved readility of figures, added
reference
Dynamics on strata of trigonal Jacobians and some integrable problems of rigid body motion
We present an algebraic geometrical and analytical description of the
Goryachev case of rigid body motion. It belongs to a family of systems sharing
the same properties: although completely integrable, they are not algebraically
integrable, their solution is not meromorphic in the complex time and involves
dynamics on the strata of the Jacobian varieties of trigonal curves.
Although the strata of hyperelliptic Jacobians have already appeared in the
literature in the context of some dynamical systems, the Goryachev case is the
first example of an integrable system whose solution involves a more general
curve. Several new features (and formulae) are encountered in the solution
given in terms of sigma-functions of such a curve.Comment: 22 pages, 1 figur
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