4,565 research outputs found
Rigid 4D N=2 supersymmetric backgrounds and actions
We classify all N=2 rigid supersymmetric backgrounds in four dimensions with
both Lorentzian and Euclidean signature that preserve eight real supercharges,
up to discrete identifications. Among the backgrounds we find specific warpings
of S^3 x R and AdS_3 x R, AdS_2 x S^2 and H^2 x S^2 with generic radii, and
some more exotic geometries. We provide the generic two-derivative rigid vector
and hypermultiplet actions and analyze the conditions imposed on the special
Kahler and hyperkahler target spaces.Comment: 50 + 17 pages; v2: minor corrections, published versio
Non-renormalization theorems and N=2 supersymmetric backgrounds
The conditions for fully supersymmetric backgrounds of general N=2 locally
supersymmetric theories are derived based on the off-shell superconformal
multiplet calculus. This enables the derivation of a non-renormalization
theorem for a large class of supersymmetric invariants with higher-derivative
couplings. The theorem implies that the invariant and its first order variation
must vanish in a fully supersymmetric background. The conjectured relation of
one particular higher-derivative invariant with a specific five-dimensional
invariant containing the mixed gauge-gravitational Chern-Simons term is
confirmed.Comment: 30 pages; v2: minor correction
Het verband tussen publiek belang en ontwerp bij het internet der dingen
Het internet der dingen levert een schat aan gegevens (“big data”) op over persoonlijk gedrag. Bij de benutting van deze gegevens is sprake van verschillende vormen van publiek belang waarvoor de overheid borgingsmechanismen in werking dient te stellen. Daarbij gaat het enerzijds om goede beschikbaarheid van gegevens, om opheffen van informatieasymmetrie als vorm van marktfalen, en anderzijds om het bieden van rechtsbescherming ten aanzien van veiligheid en privacy. In dit artikel bespreken wij hoe vanuit de principaal/agent benadering van regelgeving ten aanzien van borging van de verschillende onderdelen van het publiek belang het ontwerpproces van applicaties en systemen in het internet der dingen het best kan worden vormgegeven. Het voorbeeld van de slimme thermostaat Toon® leert hoe de samenwerking tussen ontwerpers en software ingenieurs heeft bijgedragen aan zowel een goede bescherming van de gegevens als aan een mogelijke prikkel tot energiebesparing
Deep-learned Top Tagging with a Lorentz Layer
We introduce a new and highly efficient tagger for hadronically decaying top
quarks, based on a deep neural network working with Lorentz vectors and the
Minkowski metric. With its novel machine learning setup and architecture it
allows us to identify boosted top quarks not only from calorimeter towers, but
also including tracking information. We show how the performance of our tagger
compares with QCD-inspired and image-recognition approaches and find that it
significantly increases the performance for strongly boosted top quarks.Comment: v3: minor revisions following SciPost referee report
Nonlinear sigma models with AdS supersymmetry in three dimensions
In three-dimensional anti-de Sitter (AdS) space, there exist several
realizations of N-extended supersymmetry, which are traditionally labelled by
two non-negative integers p>=q such that p+q=N. Different choices of p and q,
with N fixed, prove to lead to different restrictions on the target space
geometry of supersymmetric nonlinear sigma-models. We classify all possible
types of hyperkahler target spaces for the cases N=3 and N=4 by making use of
two different realizations for the most general (p,q) supersymmetric
sigma-models: (i) off-shell formulations in terms of N=3 and N=4 projective
supermultiplets; and (ii) on-shell formulations in terms of covariantly chiral
scalar superfields in (2,0) AdS superspace. Depending on the type of N=3,4 AdS
supersymmetry, nonlinear sigma-models can support one of the following target
space geometries: (i) hyperkahler cones; (ii) non-compact hyperkahler manifolds
with a U(1) isometry group which acts non-trivially on the two-sphere of
complex structures; (iii) arbitrary hyperkahler manifolds including compact
ones. The option (iii) is realized only in the case of critical (4,0) AdS
supersymmetry.
As an application of the (4,0) AdS techniques developed, we also construct
the most general nonlinear sigma-model in Minkowski space with a non-centrally
extended N=4 Poincare supersymmetry. Its target space is a hyperkahler cone
(which is characteristic of N=4 superconformal sigma-models), but the
sigma-model is massive. The Lagrangian includes a positive potential
constructed in terms of the homothetic conformal Killing vector the target
space is endowed with. This mechanism of mass generation differs from the
standard one which corresponds to a sigma-model with the ordinary N=4 Poincare
supersymmetry and which makes use of a tri-holomorphic Killing vector.Comment: 109 pages; V2: comments adde
dilaton Weyl multiplet in 4D supergravity
We construct the dilaton Weyl multiplet for conformal supergravity in
four dimensions. Beginning from an on-shell vector multiplet coupled to the
standard Weyl multiplet, the equations of motion can be used to eliminate the
supergravity auxiliary fields, following a similar pattern as in five and six
dimensions. The resulting 24+24 component multiplet includes two gauge vectors
and a gauge two-form and provides a variant formulation of conformal
supergravity. We also show how this dilaton Weyl multiplet is contained in the
minimal 32+32 Poincare supergravity multiplet introduced by Muller in
superspace.Comment: 15 page
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