1,080 research outputs found
Symmetry results for nonlinear elliptic operators with unbounded drift
We prove the one-dimensional symmetry of solutions to elliptic equations of
the form -\dive(e^{G(x)}a(|\nabla u|)\nabla u)=f(u) e^{G(x)}, under suitable
energy conditions. Our results hold without any restriction on the dimension of
the ambient space
Distributed interpolatory algorithms for set membership estimation
This work addresses the distributed estimation problem in a set membership
framework. The agents of a network collect measurements which are affected by
bounded errors, thus implying that the unknown parameters to be estimated
belong to a suitable feasible set. Two distributed algorithms are considered,
based on projections of the estimate of each agent onto its local feasible set.
The main contribution of the paper is to show that such algorithms are
asymptotic interpolatory estimators, i.e. they converge to an element of the
global feasible set, under the assumption that the feasible set associated to
each measurement is convex. The proposed techniques are demonstrated on a
distributed linear regression estimation problem
A Distributed Asynchronous Method of Multipliers for Constrained Nonconvex Optimization
This paper presents a fully asynchronous and distributed approach for
tackling optimization problems in which both the objective function and the
constraints may be nonconvex. In the considered network setting each node is
active upon triggering of a local timer and has access only to a portion of the
objective function and to a subset of the constraints. In the proposed
technique, based on the method of multipliers, each node performs, when it
wakes up, either a descent step on a local augmented Lagrangian or an ascent
step on the local multiplier vector. Nodes realize when to switch from the
descent step to the ascent one through an asynchronous distributed logic-AND,
which detects when all the nodes have reached a predefined tolerance in the
minimization of the augmented Lagrangian. It is shown that the resulting
distributed algorithm is equivalent to a block coordinate descent for the
minimization of the global augmented Lagrangian. This allows one to extend the
properties of the centralized method of multipliers to the considered
distributed framework. Two application examples are presented to validate the
proposed approach: a distributed source localization problem and the parameter
estimation of a neural network.Comment: arXiv admin note: substantial text overlap with arXiv:1803.0648
Lifting degeneracies in Higgs couplings using single top production in association with a Higgs boson
Current Higgs data show an ambiguity in the value of the Yukawa couplings to
quarks and leptons. Not so much because of still large uncertainties in the
measurements but as the result of several almost degenerate minima in the
coupling profile likelihood function. To break these degeneracies, it is
important to identify and measure processes where the Higgs coupling to
fermions interferes with other coupling(s). The most prominent example, the
decay of , is not sufficient to give a definitive answer.
In this Letter, we argue that -channel single top production in association
with a Higgs boson, with , can provide the necessary information
to lift the remaining degeneracy in the top Yukawa. Within the Standard Model,
the total rate is highly reduced due to an almost perfect destructive
interference in the hard process, . We first show that for
non-standard couplings the cross section can be reliably computed without
worrying about corrections from physics beyond the cutoff scale , and that it can be enhanced by more than one order of
magnitude compared to the SM. We then study the signal with 3 and 4 's in the final state, and its main backgrounds at the
LHC. We find the 8 TeV run dataset to be sensitive to the sign of the anomalous
top Yukawa coupling, while already a moderate integrated luminosity at 14 TeV
should lift the degeneracy completely.Comment: 17 pages, 7 figures. v2: inclusive signal cross sections at NLO in
QCD added; new comment on sensitivity of the analysis to t tbar h process.
Matches version accepted by JHE
Charger-mediated energy transfer for quantum batteries: an open system approach
The energy charging of a quantum battery is analyzed in an open quantum
setting, where the interaction between the battery element and the external
power source is mediated by an ancilla system (the quantum charger) that acts
as a controllable switch. Different implementations are analyzed putting
emphasis on the interplay between coherent energy pumping mechanisms and
thermalization
The role of experts in the Covid-19 pandemic and the limits of their epistemic authority in democracy
Copyright © 2020 Lavazza and Farina. This is an open-access article distributed under the terms of the Creative CommonsAttribution License (CC BY). It was originally published in Frontiers in Public Health, 14 July 2020 | Volume 8 | Article 356 (https://doi.org/10.3389/fpubh.2020.00356) and is published here with permission
Energy helps accuracy: electroweak precision tests at hadron colliders
We show that high energy measurements of Drell-Yan at the LHC can serve as
electroweak precision tests. Dimension-6 operators, from the Standard Model
Effective Field Theory, modify the high energy behavior of electroweak gauge
boson propagators. Existing measurements of the dilepton invariant mass
spectrum, from neutral current Drell-Yan at 8 TeV, have comparable sensitivity
to LEP. We propose measuring the transverse mass spectrum of charged current
Drell-Yan, which can surpass LEP already with 8 TeV data. The 13 TeV LHC will
elevate electroweak tests to a new precision frontier.Comment: 8 pages, 5 figures, 2 tables. Added: CEPC reach, projected reach on
heavy vector triplet
Charger-mediated energy transfer in exactly-solvable models for quantum batteries
We present a systematic analysis and classification of several models of
quantum batteries involving different combinations of two level systems and
quantum harmonic oscillators. In particular, we study energy transfer processes
from a given quantum system, termed charger, to another one, i.e. the proper
battery. In this setting, we analyze different figures of merit, including the
charging time, the maximum energy transfer, and the average charging power. The
role of coupling Hamiltonians which do not preserve the number of local
excitations in the charger-battery system is clarified by properly accounting
them in the global energy balance of the model.Comment: 11 page
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