Configurational and energy landscape in one-dimensional Coulomb systems

We study a one dimensional Coulomb system, where two charged colloids are neutralized by a collection of point counterions, with global neutrality. Temperature being given, two situations are addressed: the colloids are either kept at fixed positions (canonical ensemble), or the force acting on the colloids is fixed (isobaric-isothermal ensemble). The corresponding partition functions are worked out exactly, in view of determining which arrangement of counterions is optimal: how many counterions should be in the confined segment between the colloids? For the remaining ions outside, is there a left/right symmetry breakdown? We evidence a cascade of transitions, as system size is varied in the canonical treatment, or as pressure is increased in the isobaric formulation

The explosion in U.S. wealth inequality has been fuelled bystagnant wages, increasing debt, and a collapse in assetvalues for the middle classes

Income and economic equality have been on the rise in recent decades – but has this trend been fuelled only by increasing pay packets for the richest, or has wealth inequality risen as well? Emmanuel Saez and Gabriel Zucman find that over the past three decades the share of household wealth owned by the top 0.1 percent has increased from 7 to 22 percent. They write that the growing indebtedness of most Americans through mortgage and credit card obligations, combined with the collapse in the value of their assets during the Great Recession, and stagnant real wages have led to the erosion of the wealth share of the bottom 90 percent of families. They warn that without policies to reduce the concentration of wealth, such as estate taxes, within two decades the gains in wealth democratization which occurred in the New Deal and after World War II may well be lost

A Temporal Coherence Loss Function for Learning Unsupervised Acoustic Embeddings

AbstractWe train neural networks of varying depth with a loss function which imposes the output representations to have a temporal profile which looks like that of phonemes. We show that a simple loss function which maximizes the dissimilarity between near frames and long distance frames helps to construct a speech embedding that improves phoneme discriminability, both within and across speakers, even though the loss function only uses within speaker information. However, with too deep an architecture, this loss function yields overfitting, suggesting the need for more data and/or regularization

Free energy of cylindrical polyions: analytical results

Within the Poisson-Boltzmann (PB) framework useful for a wealth of charged soft matter problems, we work out the Coulombic grand potential of a long cylindrical charged polyion in a binary electrolyte solution of arbitrary valency and for low salt concentration. We obtain the exact analytical low-salt asymptotic expression for the grand potential, derived from known properties of the exact solutions to the cylindrical PB equation. These results are relevant for understanding nucleic acid processes. In practice, our expressions are accurate for arbitrary polyion charges, provided their radius is smaller than the Debye length defined by the electrolyte

Searches for new physics with leptons and invisible particles at the ATLAS experiment at the LHC

The Standard Model of Particle Physics (SM), while successful at describing almost all subatomic phenomena observed to date, has some glaring open questions: the Higgs boson mass is unstable at high energies, there is no dark matter candidate, and the prediction and measurement of (g-2)_mu are in tension. Supersymmetric (SUSY) extensions to the Standard Model could provide possible answers to all these problems, and some SUSY particles could be produced at the Large Hadron Collider. This thesis describes three areas of work aimed at finding evidence for SUSY at the ATLAS Experiment of the Large Hadron Collider. First, the performance and development of the ATLAS ETmiss trigger is discussed. Many theorised SUSY process are predicted to produce events with ETmiss, a large imbalance in the momentum sum of detectable particles, as SUSY particles could escape detection. The ETmiss trigger aims to select such events during data-taking to be saved to disk for analysis. Next, a search for new physics in events with four or more leptons is described. This search is optimised for certain SUSY models, but is also sensitive to a wide range of beyond-the-Standard-Model (BSM) processes. No significant deviation from the SM is observed. From this observation, limits are set on general gauge-mediated SUSY models, R-parity violating SUSY models, and BSM contributions. Finally, a machine-learning-based strategy is proposed to probe an experimentally challenging but phenomenologically favoured range of SUSY parameters in events with two leptons and ETmiss. The strategy is found to not only be competitive with a more traditional cuts-based strategy, but it also provides the event yields necessary for the measurement of SUSY particle properties