Electroweak lights from Dark Matter annihilations

The energy spectra of Standard Model particles originated from Dark Matter annihilations can be significantly altered by the inclusion of electroweak gauge boson radiation from the final state. A situation where this effect is particularly important is when a Majorana Dark Matter particle annihilates into two light fermions. This process is in p-wave and hence suppressed by the small value of the relative velocity of the annihilating particles. The inclusion of electroweak radiation eludes this suppression and opens up a potentially sizeable s-wave contribution to the annihilation cross section. I will discuss the impact of this effect on the fluxes of stable particles resulting from the Dark Matter annihilations, which are relevant for Dark Matter indirect searches.Comment: 4 pages, 2 figures. Contribution to the conference proceedings of TAUP 2011, Munich - Germany (5-9 September 2011

The phase-locked mean impulse response of a turbulent channel flow

We describe the first DNS-based measurement of the complete mean response of a turbulent channel flow to small external disturbances. Space-time impulsive perturbations are applied at one channel wall, and the linear response describes their mean effect on the flow field as a function of spatial and temporal separations. The turbulent response is shown to differ from the response a laminar flow with the turbulent mean velocity profile as base flow.Comment: Accepted for publication in Physics of Fluid

Versatile surrogate models for IC buffers

In previous papers [1,2] the authors have investigated the use of Volterra series in the identification of IC buffer macro-models. While the approach benefited from some of the inherent qualities of Volterra series it preserved the two-state paradigm of earlier methods (see [3] and its references) and was thus limited in its versatility. In the current paper the authors tackle the challenge of going beyond an application or device-oriented approach and build versatile surrogate models that mimic the behavior of IC buffers over a wide frequency band and for a variety of loads thus achieving an unprecedented degree of generality. This requires the use of a more general system identification paradig

Which sexual abuse victims receive a forensic medical examination? : The impact of Children\u27s Advocacy Centers

Abstract Objective This study examines the impact of Children\u27s Advocacy Centers (CAC) and other factors, such as the child\u27s age, alleged penetration, and injury on the use of forensic medical examinations as part of the response to reported child sexual abuse. Methods This analysis is part of a quasi-experimental study, the Multi-Site Evaluation of Children\u27s Advocacy Centers, which evaluated four CACs relative to within-state non-CAC comparison communities. Case abstractors collected data on forensic medical exams in 1,220 child sexual abuse cases through review of case records. Results Suspected sexual abuse victims at CACs were two times more likely to have forensic medical examinations than those seen at comparison communities, controlling for other variables. Girls, children with reported penetration, victims who were physically injured while being abused, White victims, and younger children were more likely to have exams, controlling for other variables. Non-penetration cases at CACs were four times more likely to receive exams as compared to those in comparison communities. About half of exams were conducted the same day as the reported abuse in both CAC and comparison communities. The majority of caregivers were very satisfied with the medical professional. Receipt of a medical exam was not associated with offenders being charged. Conclusions Results of this study suggest that CACs are an effective tool for furthering access to forensic medical examinations for child sexual abuse victims

The Finite Size Error in Many-body Simulations with long-Ranged Interactions

We discuss the origin of the finite size error of the energy in many-body simulation of systems of charged particles and we propose a correction based on the random phase approximation at long wave lengths. The correction comes from contributions mainly determined by the organized collective oscillations of the interacting system. Finite size corrections, both on kinetic and potential energy, can be calculated within a single simulation. Results are presented for the electron gas and silicon.Comment: 4 pages, 4 figures, submitted to PRL; corrected typo

Dynamics of entanglement in quantum computers with imperfections

The dynamics of the pairwise entanglement in a qubit lattice in the presence of static imperfections exhibits different regimes. We show that there is a transition from a perturbative region, where the entanglement is stable against imperfections, to the ergodic regime, in which a pair of qubits becomes entangled with the rest of the lattice and the pairwise entanglement drops to zero. The transition is almost independent of the size of the quantum computer. We consider both the case of an initial maximally entangled and separable state. In this last case there is a broad crossover region in which the computer imperfections can be used to create a significant amount of pairwise entanglement.Comment: 4 pages, 4 figure

Accuracy of a teleported trapped field state inside a single bimodal cavity

We propose a simplified scheme to teleport a superposition of coherent states from one mode to another of the same bimodal lossy cavity. Based on current experimental capabilities, we present a calculation of the fidelity that can be achieved, demonstrating accurate teleportation if the mean photon number of each mode is at most 1.5. Our scheme applies as well for teleportation of coherent states from one mode of a cavity to another mode of a second cavity, both cavities embedded in a common reservoir.Comment: 4 pages, 2 figures, in appreciation for publication in Physical Review