Kondo effect in graphene with Rashba spin-orbit coupling

We study the Kondo screening of a magnetic impurity adsorbed in graphene in the presence of Rashba spin-orbit interaction. The system is described by an effective single-channel Anderson impurity model, which we analyze using the numerical renormalization group. The nontrivial energy dependence of the host density of states gives rise to interesting behaviors under variation of the chemical potential or the spin-orbit coupling. Varying the Rashba coupling produces strong changes in the Kondo temperature characterizing the many-body screening of the impurity spin, and at half filling allows approach to a quantum phase transition separating the strong-coupling Kondo phase from a free-moment phase. Tuning the chemical potential close to sharp features of the hybridization function results in striking features in the temperature dependences of thermodynamic quantities and in the frequency dependence of the impurity spectral function.Comment: 11 pages, 9 figures. Minor changes. Accepted in PR

Direct laser acceleration of electrons in free-space

Compact laser-driven accelerators are versatile and powerful tools of unarguable relevance on societal grounds for the diverse purposes of science, health, security, and technology because they bring enormous practicality to state-of-the-art achievements of conventional radio-frequency accelerators. Current benchmarking laser-based technologies rely on a medium to assist the light-matter interaction, which impose material limitations or strongly inhomogeneous fields. The advent of few cycle ultra-intense radially polarized lasers has materialized an extensively studied novel accelerator that adopts the simplest form of laser acceleration and is unique in requiring no medium to achieve strong longitudinal energy transfer directly from laser to particle. Here we present the first observation of direct longitudinal laser acceleration of non-relativistic electrons that undergo highly-directional multi-GeV/m accelerating gradients. This demonstration opens a new frontier for direct laser-driven particle acceleration capable of creating well collimated and relativistic attosecond electron bunches and x-ray pulses

Signatures of quantum phase transitions in parallel quantum dots: Crossover from local-moment to underscreened spin-1 Kondo physics

We study a strongly interacting "quantum dot 1" and a weakly interacting "dot 2" connected in parallel to metallic leads. Gate voltages can drive the system between Kondo-quenched and non-Kondo free-moment phases separated by Kosterlitz-Thouless quantum phase transitions. Away from the immediate vicinity of the quantum phase transitions, the physical properties retain signatures of first-order transitions found previously to arise when dot 2 is strictly noninteracting. As interactions in dot 2 become stronger relative to the dot-lead coupling, the free moment in the non-Kondo phase evolves smoothly from an isolated spin-one-half in dot 1 to a many-body doublet arising from the incomplete Kondo compensation by the leads of a combined dot spin-one. These limits, which feature very different spin correlations between dot and lead electrons, can be distinguished by weak-bias conductance measurements performed at finite temperatures.Comment: 7 pages, 7 figures. Accepted for publication in Phys. Rev.

Laser-Induced Linear Electron Acceleration in Free Space

Linear acceleration in free space is a topic that has been studied for over 20 years, and its ability to eventually produce high-quality, high energy multi-particle bunches has remained a subject of great interest. Arguments can certainly be made that such an ability is very doubtful. Nevertheless, we chose to develop an accurate and truly predictive theoretical formalism to explore this remote possibility in a computational experiment. The formalism includes exact treatment of Maxwell's equations, exact relativistic treatment of the interaction among the multiple individual particles, and exact treatment of the interaction at near and far field. Several surprising results emerged. For example, we find that 30 keV electrons (2.5% energy spread) can be accelerated to 7.7 MeV (2.5% spread) and to 205 MeV (0.25% spread) using 25 mJ and 2.5 J lasers respectively. These findings should hopefully guide and help develop compact, high-quality, ultra-relativistic electron sources, avoiding conventional limits imposed by material breakdown or structural constraints.Comment: Supplementary Information starts on pg 1

GoRela: Go Relative for Viewpoint-Invariant Motion Forecasting

The task of motion forecasting is critical for self-driving vehicles (SDVs) to be able to plan a safe maneuver. Towards this goal, modern approaches reason about the map, the agents' past trajectories and their interactions in order to produce accurate forecasts. The predominant approach has been to encode the map and other agents in the reference frame of each target agent. However, this approach is computationally expensive for multi-agent prediction as inference needs to be run for each agent. To tackle the scaling challenge, the solution thus far has been to encode all agents and the map in a shared coordinate frame (e.g., the SDV frame). However, this is sample inefficient and vulnerable to domain shift (e.g., when the SDV visits uncommon states). In contrast, in this paper, we propose an efficient shared encoding for all agents and the map without sacrificing accuracy or generalization. Towards this goal, we leverage pair-wise relative positional encodings to represent geometric relationships between the agents and the map elements in a heterogeneous spatial graph. This parameterization allows us to be invariant to scene viewpoint, and save online computation by re-using map embeddings computed offline. Our decoder is also viewpoint agnostic, predicting agent goals on the lane graph to enable diverse and context-aware multimodal prediction. We demonstrate the effectiveness of our approach on the urban Argoverse 2 benchmark as well as a novel highway dataset

La comunicación en los programas sociales de lucha contra la pobreza : el caso del Programa Juntos en la Región de Junín

La presente investigación nace motivada por aproximaciones teóricas del investigador a los procesos históricos a los que se ha enfrentado el Perú, un país que ha atravesado diversos sistemas políticos, fenómenos migratorios y una búsqueda constante por pensarnos como una nación con identidad propia, estos factores entre algunos otros más, nos podrían dar, en principio, luces para una comprensión integral de esta sociedad.Tesi

Hyperpolarization-activated cyclic nucleotide-gated 2 (HCN2) ion channels drive pain in mouse models of diabetic neuropathy

Blocking HCN2 ion channel activity in peripheral nociceptive neurons alleviates the pain hypersensitivity associated with diabetic neuropathy.</jats:p