Elastic scattering and the proton form factor

We compute the differential and the total cross sections for $pp$ scattering using the QCD pomeron model proposed by Landshoff and Nachtmann. This model is quite dependent on the experimental electromagnetic form factor, and it is not totally clear why this form factor gives good results even at moderate transferred momentum. We exchange the eletromagnetic form factor by the asymptotic QCD proton form factor determined by Brodsky and Lepage (BL) plus a prescription for its low energy behavior dictated by the existence of a dynamically generated gluon mass. We fit the data with this QCD inspired form factor and a value for the dynamical gluon mass consistent with the ones determined in the literature. Our results also provide a new determination of the proton wave function at the origin, which appears in the BL form factor.Comment: 10 pages, 2 figures. Submitted to Physics Letters B. Submitted to Phys. Lett.

Statistical stability of equilibrium states for interval maps

We consider families of multimodal interval maps with polynomial growth of the derivative along the critical orbits. For these maps Bruin and Todd have shown the existence and uniqueness of equilibrium states for the potential $\phi_t:x\mapsto-t\log|Df(x)|$, for $t$ close to 1. We show that these equilibrium states vary continuously in the weak$^*$ topology within such families. Moreover, in the case $t=1$, when the equilibrium states are absolutely continuous with respect to Lebesgue, we show that the densities vary continuously within these families.Comment: More details given and the appendices now incorporated into the rest of the pape

Yukawa particles confined in a channel and subject to a periodic potential: ground state and normal modes

We consider a classical system of two-dimensional (2D) charged particles, which interact through a repulsive Yukawa potential $exp(-r/\lambda)/r$, confined in a parabolic channel which limits the motion of the particles in the $y$-direction. Along the $x$-direction, the particles are also subject to a periodic potential substrate. The ground state configurations and the normal mode spectra of the system are obtained as function of the periodicity and strength of the periodic potential ($V_0$), and density. An interesting set of tunable ground state configurations are found, with first and second order structural transitions between them. A magic configuration with particles aligned in each minimum of the periodic potential is obtained for V_0 larger than some critical value which has a power law dependence on the density. The phonon spectrum of different configurations were also calculated. A localization of the modes into a small frequency interval is observed for a sufficient strength of the periodic potential. A tunable band-gap is found as a function of $V_0$. This model system can be viewed as a generalization of the Frenkel and Kontorova model.Comment: Submmited to PR

Experimental Observation of Quantum Correlations in Modular Variables

We experimentally detect entanglement in modular position and momentum variables of photon pairs which have passed through $D$-slit apertures. We first employ an entanglement criteria recently proposed in [Phys. Rev. Lett. {\bf 106}, 210501 (2011)], using variances of the modular variables. We then propose an entanglement witness for modular variables based on the Shannon entropy, and test it experimentally. Finally, we derive criteria for Einstein-Podolsky-Rosen-Steering correlations using variances and entropy functions. In both cases, the entropic criteria are more successful at identifying quantum correlations in our data.Comment: 7 pages, 4 figures, comments welcom

Flexible force sensors for e-textiles

This paper presents the development of inexpensive, lightweight, flexible polymer-based piezoresistive sensors appropriate for integration in e-textiles. The transducing element used is a volume-conductive carbon impregnated black polypropylene/polyethylene film with commercial names Velostat (from 3M) or Linqstat (from Caplinq). The objective is to investigate on the influence of different sensor constructions, varying film thicknesses, electrode materials and encapsulations on sensor performance. Furthermore, ways of integrating the sensors into textile products, as well as potential applications are also studied. In this paper, the behaviour of the sensors under different cyclic compression loads, applied at different speeds, is presented. Sensors using three different electrode materials are tested. The results show significant influence of sensor construction and electrode material on the static and dynamic performance of the devices.This work is financed by Project “Deus ex Machina”, NORTE-01-0145-FEDER-000026, funded by CCDRN, through Sistema de Apoio à Investigação Cientifica e Tecnológica (Projetos Estruturados I&D&I) of Programa Operacional Regional do Norte, from Portugal 2020. Acknowledgements also to IAPMEI for funding under the program “Startup Voucher” 2017, project MAPS.info:eu-repo/semantics/publishedVersio

Bayesian Non-Exhaustive Classification A Case Study: Online Name Disambiguation using Temporal Record Streams

The name entity disambiguation task aims to partition the records of multiple real-life persons so that each partition contains records pertaining to a unique person. Most of the existing solutions for this task operate in a batch mode, where all records to be disambiguated are initially available to the algorithm. However, more realistic settings require that the name disambiguation task be performed in an online fashion, in addition to, being able to identify records of new ambiguous entities having no preexisting records. In this work, we propose a Bayesian non-exhaustive classification framework for solving online name disambiguation task. Our proposed method uses a Dirichlet process prior with a Normal * Normal * Inverse Wishart data model which enables identification of new ambiguous entities who have no records in the training data. For online classification, we use one sweep Gibbs sampler which is very efficient and effective. As a case study we consider bibliographic data in a temporal stream format and disambiguate authors by partitioning their papers into homogeneous groups. Our experimental results demonstrate that the proposed method is better than existing methods for performing online name disambiguation task.Comment: to appear in CIKM 201