1,489 research outputs found
Empowering Active Learning to Jointly Optimize System and User Demands
Existing approaches to active learning maximize the system performance by
sampling unlabeled instances for annotation that yield the most efficient
training. However, when active learning is integrated with an end-user
application, this can lead to frustration for participating users, as they
spend time labeling instances that they would not otherwise be interested in
reading. In this paper, we propose a new active learning approach that jointly
optimizes the seemingly counteracting objectives of the active learning system
(training efficiently) and the user (receiving useful instances). We study our
approach in an educational application, which particularly benefits from this
technique as the system needs to rapidly learn to predict the appropriateness
of an exercise to a particular user, while the users should receive only
exercises that match their skills. We evaluate multiple learning strategies and
user types with data from real users and find that our joint approach better
satisfies both objectives when alternative methods lead to many unsuitable
exercises for end users.Comment: To appear as a long paper in Proceedings of the 58th Annual Meeting
of the Association for Computational Linguistics (ACL 2020). Download our
code and simulated user models at github:
https://github.com/UKPLab/acl2020-empowering-active-learnin
Holographic Estimate of Oblique Corrections for Technicolor
We study the oblique corrections to the electroweak interaction in the
holographic model of technicolor theories. The oblique S parameter is expressed
in terms of a solution to the equations of motion for the AdS bulk gauge
fields. By analyzing the solution, we establish a rigorous proof that the S
parameter is positive and is reduced by walking. We also present the precise
numerical values for the S parameter of various technicolor models by solving
the equations numerically.Comment: 10 pages, 1 figure, RevTeX 4.0: published version. references adde
Chiral Electronics
We consider the properties of electric circuits involving Weyl semimetals.
The existence of the anomaly-induced chiral magnetic current in a Weyl
semimetal subjected to magnetic field causes an interesting and unusual
behavior of such circuits. We consider two explicit examples: i) a circuit
involving the "chiral battery" and ii) a circuit that can be used as a "quantum
amplifier" of magnetic field. The unique properties of these circuits stem from
the chiral anomaly and may be utilized for creating "chiral electronic"
devices.Comment: 5 pages, 2 figures; final version to appear in Physical Review
Chiral Dynamics of Baryons from String Theory
We study baryons in an AdS/CFT model of QCD by Sakai and Sugimoto, realized
as small instantons with fundamental string hairs. We introduce an effective
field theory of the baryons in the five-dimensional setting, and show that the
instanton interpretation implies a particular magnetic coupling. Dimensional
reduction to four dimensions reproduces the usual chiral effective action, and
in particular we estimate the axial coupling between baryons and pions
and the magnetic dipole moments, both of which are proportional to . We
extrapolate to finite and discuss subleading corrections.Comment: 4 pages, typos fixed, discussions reworded to clarify a unit, a
reference update
Holographic Nuclear Matter in AdS/QCD
We study the physics with finite nuclear density in the framework of AdS/QCD
with holographic baryon field included. Based on a mean field type approach, we
introduce the nucleon density as a bi-fermion condensate of the lowest mode of
the baryon field and calculate the density dependence of the chiral condensate
and the nucleon mass. We observe that the chiral condensate as well as the mass
of nucleon decrease with increasing nuclear density. We also consider the mass
splitting of charged vector mesons in iso-spin asymmetric nuclear matter.Comment: 16 pages, 3 figures, two references are added, typo corrected,
section 3.3 remove
1/2 BPS Geometries of M2 Giant Gravitons
We construct the general 1/2 BPS M2 giant graviton solutions asymptotic to
the eleven-dimensional maximally supersymmetric plane wave background, based on
the recent work of Lin, Lunin and Maldacena. The solutions have null
singularity and we argue that it is unavoidable to have null singularity in the
proposed framework, although the solutions are still physically relevant. They
involve an arbitrary function F(x) which is shown to have a correspondence to
the 1/2 BPS states of the BMN matrix model. A detailed map between the 1/2 BPS
states of both sides is worked out.Comment: 21 pages and 1 figure. v2: references added, comments adde
New BPS Objects in N=2 Supersymmetric Gauge Theories
We explore BPS soliton configurations in N=2 supersymmetric Yang-Mills theory
with matter fields arising from parallel D3 branes on D7 branes. Especially we
focus on two parameter family of 1/8 BPS equations, dyonic objects, and 1/8 BPS
objects and raise a possibility of absence of BPS vortices when the number of
D3 branes is larger than that of D7 branes.Comment: 28 pages, LaTeX, no figur
Chiral magnetic wave at finite baryon density and the electric quadrupole moment of quark-gluon plasma in heavy ion collisions
Chiral Magnetic Wave (CMW) is a gapless collective excitation of quark-gluon
plasma in the presence of external magnetic field that stems from the interplay
of Chiral Magnetic (CME) and Chiral Separation Effects (CSE); it is composed by
the waves of the electric and chiral charge densities coupled by the axial
anomaly. We consider CMW at finite baryon density and find that it induces the
electric quadrupole moment of the quark-gluon plasma produced in heavy ion
collisions: the "poles" of the produced fireball (pointing outside of the
reaction plane) acquire additional positive electric charge, and the "equator"
acquires additional negative charge. We point out that this electric quadrupole
deformation lifts the degeneracy between the elliptic flows of positive and
negative pions leading to , and estimate the magnitude
of the effect.Comment: 4 pages, 3 figure
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