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An Exploration of Spotted White Dwarfs from K2
The 21st European Workshop on White Dwarfs was held in Austin, TX from July 23rd to 27th of 2018The Kepler K2 mission has discovered a significant
population of white dwarf stars that exhibit
photometric variability due to surface inhomogeneities
likely related to magnetism. These “spotted”
white dwarfs present not only in temperature
regimes where we expect convection to dominate
white dwarf photospheres, but also where
radiation should dominate. We present an exploration
of spotted white dwarfs as a function of
various physical characteristics, including temperature,
magnetic field strength, and rotational period,
in order to better understand the origins of
these photometric variations.Astronom
Detecting entanglement in spatial interference
We discuss an experimentally amenable class of two-particle states of motion
giving rise to nonlocal spatial interference under position measurements. Using
the concept of modular variables, we derive a separability criterion which is
violated by these non-Gaussian states. While we focus on the free motion of
material particles, the presented results are valid for any pair of canonically
conjugate continuous variable observables and should apply to a variety of
bipartite interference phenomena.Comment: 4 pages; corresponds to published versio
Dusty Exoplanetary Debris Disks in the Single-Temperature Blackbody Plane
The 21st European Workshop on White Dwarfs was held in Austin, TX from July 23rd to 27th of 2018We present a bulk sample analysis of the metal
polluted white dwarfs which also host infrared
bright dusty debris disks, known to be direct signatures
of an active exoplanetary accretion source.
We explore the relative positions of these systems
in a “single-temperature blackbody plane”, defined
as the temperature and radius of a single temperature
blackbody as fitted to the infrared
excess. We find that the handful of dust systems
which also host gaseous debris in emission
congregate along the high temperature boundary
of the dust disk region in the single-temperature
blackbody plane. We discuss interpretations of
this boundary and propose the single-temperature
blackbody plane selection technique for use in future
targeted searches of gaseous emission.Astronom
Bell test for the free motion of material particles
We present a scheme to establish non-classical correlations in the motion of
two macroscopically separated massive particles without resorting to
entanglement in their internal degrees of freedom. It is based on the
dissociation of a diatomic molecule with two temporally separated Feshbach
pulses generating a motional state of two counter-propagating atoms that is
capable of violating a Bell inequality by means of correlated single particle
interferometry. We evaluate the influence of dispersion on the Bell
correlation, showing it to be important but manageable in a proposed
experimental setup. The latter employs a molecular BEC of fermionic Lithium
atoms, uses laser-guided atom interferometry, and seems to be within the reach
of present-day technology.Comment: 4 pages, 1 figure; corresponds to published versio
The Suppression of Diversity
Is it a systematic strategy or a mutation of millennial ferver that drives the escalating challenges to the civil rights of this nation\u27s racial, linguistic, and national origin minorities? Increasing juridical, legislative, and popular assaults on affirmative action policies coupled with the sometimes less heralded emergence of a de facto U.S. language policy are sweeping through the states. These activities draw on a consistent repertoire of approaches from the invocation of the very language and concepts of the civil rights movement to the isolationist buzz-words of early twentieth century advocates of Americanization. In an effort to legitimize their efforts this new breed of assailants has lifted the terms equality of opportunity, color blind, and merit directly from the lips of civil rights heroes of the past, retrofitting concepts that resonate from the very core of the civil rights movement into an arsenal of weapons that threaten the extinction of that movement. In that same vein opponents of bilingual education have reached further back into our history dredging up de-contextualized quotations from icons of American history to evoke nostalgia and patriotism and to resuscitate the fear of the dissolution of national unity in the wake of the infusion of diverse languages and cultures. The introductory portion of this article treats the failure of anti-civil rights movements to acknowledge either the rich cultural legacy of people of color or the deeply engrained cultural and political limitations that this nation has imposed on their civil rights. We discuss the re-packaged language of equality and equity used by these movements and their success and attempts at success in reversing the progress of civil rights at the polls and in legislatures across the nation. We next examine the anti-affirmative action and anti-bilingual movements sweeping the U.S. today, analyzing qualitative and quantitative data from multiple sources including data from the the 2000 U.S. Census to track current anti-affirmative action and anti-bilingual/English only developments among the states to demonstrate the coexistence of these developments in those areas where people of color are concentrated
Term Graph Representations for Cyclic Lambda-Terms
We study various representations for cyclic lambda-terms as higher-order or
as first-order term graphs. We focus on the relation between
`lambda-higher-order term graphs' (lambda-ho-term-graphs), which are
first-order term graphs endowed with a well-behaved scope function, and their
representations as `lambda-term-graphs', which are plain first-order term
graphs with scope-delimiter vertices that meet certain scoping requirements.
Specifically we tackle the question: Which class of first-order term graphs
admits a faithful embedding of lambda-ho-term-graphs in the sense that: (i) the
homomorphism-based sharing-order on lambda-ho-term-graphs is preserved and
reflected, and (ii) the image of the embedding corresponds closely to a natural
class (of lambda-term-graphs) that is closed under homomorphism?
We systematically examine whether a number of classes of lambda-term-graphs
have this property, and we find a particular class of lambda-term-graphs that
satisfies this criterion. Term graphs of this class are built from application,
abstraction, variable, and scope-delimiter vertices, and have the
characteristic feature that the latter two kinds of vertices have back-links to
the corresponding abstraction.
This result puts a handle on the concept of subterm sharing for higher-order
term graphs, both theoretically and algorithmically: We obtain an easily
implementable method for obtaining the maximally shared form of
lambda-ho-term-graphs. Also, we open up the possibility to pull back properties
from first-order term graphs to lambda-ho-term-graphs. In fact we prove this
for the property of the sharing-order successors of a given term graph to be a
complete lattice with respect to the sharing order.
This report extends the paper with the same title
(http://arxiv.org/abs/1302.6338v1) in the proceedings of the workshop TERMGRAPH
2013.Comment: 35 pages. report extending proceedings article on arXiv:1302.6338
(changes with respect to version v2: added section 8, modified Proposition
2.4, added Remark 2.5, added Corollary 7.11, modified figures in the
conclusion
A Quantitative Non-radial Oscillation Model for the Subpulses in PSR B0943+10
In this paper, we analyze time series measurements of PSR B0943+10 and fit
them with a non-radial oscillation model. The model we apply was first
developed for total intensity measurements in an earlier paper, and expanded to
encompass linear polarization in a companion paper to this one. We use PSR
B0943+10 for the initial tests of our model because it has a simple geometry,
it has been exhaustively studied in the literature, and its behavior is
well-documented. As prelude to quantitative fitting, we have reanalyzed
previously published archival data of PSR B0943+10 and uncovered subtle but
significant behavior that is difficult to explain in the framework of the
drifting spark model. Our fits of a non-radial oscillation model are able to
successfully reproduce the observed behavior in this pulsar.Comment: 45 pages, 16 figures, accepted Ap
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