34,841 research outputs found
Dynamical generation and detection of entanglement in neutral leviton pairs
The entanglement of coherently split electron-hole pairs in an electronic
conductor is typically not considered accessible due to particle number
conservation and fermionic super-selection rules. We demonstrate here that
current cross-correlation measurements at the outputs of an electronic
Mach-Zehnder interferometer can nevertheless provide a robust witness of
electron-hole entanglement. Specifically, we consider neutral excitations
generated by modulating the transmission of an unbiased quantum point contact
periodically in time. For an optimized modulation profile, an entangled state
with one positively-charged leviton (a hole) and one negatively-charged leviton
(an electron) gets delocalized over the two paths of the interferometer and is
detected at the output arms. We evaluate the influence of finite electronic
temperatures and dephasing corresponding to recent experiments.Comment: 5 pages, 3 figures, 1 page of Supplemental Materia
First European interception of the brown fir longhorn beetle, Callidiellum villosulum (Fairmaire, 1900) (Coleoptera, Cerambycidae)
A specimen of the brown fir longhorn beetle, Callidiellum villosulum villosulum found in Malta represents the first record of this invasive species for Europe. Historical details on world invasion of this species are provided as well as a short description, origin and biology. A brief pest risk analysis of this species is also presented.peer-reviewe
Cylindric Reverse Plane Partitions and 2D TQFT
The ring of symmetric functions carries the structure of a Hopf algebra. When
computing the coproduct of complete symmetric functions one arrives
at weighted sums over reverse plane partitions (RPP) involving binomial
coefficients. Employing the action of the extended affine symmetric group at
fixed level we generalise these weighted sums to cylindric RPP and define
cylindric complete symmetric functions. The latter are shown to be
-positive, that is, their expansions coefficients in the basis of complete
symmetric functions are non-negative integers. We state an explicit formula in
terms of tensor multiplicities for irreducible representations of the
generalised symmetric group. Moreover, we relate the cylindric complete
symmetric functions to a 2D topological quantum field theory (TQFT) that is a
generalisation of the celebrated -Verlinde algebra
or Wess-Zumino-Witten fusion ring, which plays a prominent role in the context
of vertex operator algebras and algebraic geometry.Comment: 13 pages, 1 figure, accepted conference proceedings article for
FPSAC2018 (Hanover
Coalescence of Euclidean geodesics on the Poisson-Delaunay triangulation
Let us consider Euclidean first-passage percolation on the Poisson-Delaunay
triangulation. We prove almost sure coalescence of any two semi-infinite
geodesics with the same asymptotic direction. The proof is based on an adapted
Burton-Keane argument and makes use of the concentration property for
shortest-path lengths in the considered graphs. Moreover, by considering the
specific example of the relative neighborhood graph, we illustrate that our
approach extends to further well-known graphs in computational geometry. As an
application, we show that the expected number of semi-infinite geodesics
starting at a given vertex and leaving a disk of a certain radius grows at most
sublinearly in the radius.Comment: 21 pages, 7 figure
Spectrally Similar Incommensurable 3-Manifolds
Reid has asked whether hyperbolic manifolds with the same geodesic length spectrum must be commensurable. Building toward a negative answer to this question, we construct examples of hyperbolic 3–manifolds that share an arbitrarily large portion of the length spectrum but are not commensurable. More precisely, for every n ≫ 0, we construct a pair of incommensurable hyperbolic 3–manifolds Nn and Nµn whose volume is approximately n and whose length spectra agree up to length n.
Both Nn and Nµn are built by gluing two standard submanifolds along a complicated pseudo-Anosov map, ensuring that these manifolds have a very thick collar about an essential surface. The two gluing maps differ by a hyper-elliptic involution along this surface. Our proof also involves a new commensurability criterion based on pairs of pants
Maty's Biography of Abraham De Moivre, Translated, Annotated and Augmented
November 27, 2004, marked the 250th anniversary of the death of Abraham De
Moivre, best known in statistical circles for his famous large-sample
approximation to the binomial distribution, whose generalization is now
referred to as the Central Limit Theorem. De Moivre was one of the great
pioneers of classical probability theory. He also made seminal contributions in
analytic geometry, complex analysis and the theory of annuities. The first
biography of De Moivre, on which almost all subsequent ones have since relied,
was written in French by Matthew Maty. It was published in 1755 in the Journal
britannique. The authors provide here, for the first time, a complete
translation into English of Maty's biography of De Moivre. New material, much
of it taken from modern sources, is given in footnotes, along with numerous
annotations designed to provide additional clarity to Maty's biography for
contemporary readers.Comment: Published at http://dx.doi.org/10.1214/088342306000000268 in the
Statistical Science (http://www.imstat.org/sts/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Information-not-thing: further problems with and alternatives to the belief that information is physical
In this short paper, we show that a popular view in information science, information-as-thing, fails to account for a common example of information that seems physical. We then demonstrate how the distinction between types and tokens, recently used to analyse Shannon information, can account for this same example by viewing information as abstract, and discuss existing definitions of information that are consistent with this approach.
Dans ce court article nous montrons qu'une vision populaire en sciences de l'information, l'information en tant qu’une chose, échoue à rendre compte d'un exemple commun d'information qui semble physique. Nous démontrons ensuite comment la distinction type/token, utilisée récemment pour analyser l'information de Shannon, peut rendre compte de ce même exemple en considérant l'information comme abstraite, et nous discutons des définitions existantes de l’information qui sont compatibles avec cette approche
Scale-invariant Perturbations from Chaotic Inflation
Vacuum fluctuations in the inflaton field driving chaotic inflation with a
quadratic potential give a red spectrum of primordial density perturbations,
n=0.97. However angular fluctuations in an O(N)-symmetric quadratic potential
have a very nearly scale-invariant spectrum, n=0.9998. We investigate the
possibility that these isocurvature field perturbations could give the dominant
contribution to the primordial density perturbation after inflation.Comment: 10 pages, LaTeX with RevTex, no figure
- …