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Trapped-ion quantum platforms are subject to "anomalous" heating due to interactions with electric-field noise sources of nature not yet completely known. There is ample experimental evidence that this noise originates at the surfaces of the trap electrodes, and models assuming fluctuating pointlike dipoles are consistent with observations, but the exact microscopic mechanisms behind anomalous heating remain undetermined. Here we show how a two-ion probe displays a transition in its dissipation properties, enabling experimental access to the mean orientation of the dipoles and the spatial extent of dipole-dipole correlations. This information can be used to test the validity of candidate microscopic models, which predict correlation lengths spanning several orders of magnitude. Furthermore, we propose an experiment to measure these effects with currently available traps and techniques. ; This work has been supported by the European Union through the H2020 Project QuProCS (Grant No. 641277), by MINECO/AEI/FEDER through NoMaQ Project No. FIS2014-60343-P, QuStruct Project No. FIS2015-66860-P, and EPheQuCS Project No. FIS2016-78010-P. The research is partly based upon work supported by the Office of the Director of National Intelligence (ODNI), Intelligence Advanced Research Projects Activity (IARPA), via the U.S. Army Research Office Grant No. W911NF-16-1-0070. necessarily reflect the view of the U.S. Army Research Office. ; Peer reviewed

This paper describes the results of vehicle-to-vehicle (V2V) and infrastructure-to-vehicle (I2V) experiments implementing cooperative maneuvering for three different vehicles driving automatically. The cars used were cybercars from the Institut National de Recherche en Informatique et Automatique (INRIA), (France), which are fully automated road vehicles, and two mass-produced cars-one a Smart Fortwo car from TNO (Netherlands) equipped with additional actuators and sensors and the other a convertible Citroe¨n C3 from IAI (Spain) that uses sensorial information to manage the actuators. The cars communicate by a wireless mesh network over Wi-Fi using the optimized link state routing (OLSR) ad-hoc protocol. The entire communication task is embedded in a small MIPS Linux Box (4G System Cube) that is transparent for the cars. A standard framework was defined with the parameters needed to perform adaptive cruise control (ACC) and intersection maneuvers among the cars, as well as emergency stops via a signal sent by the infrastructure. The experiments were carried out in La Rochelle (France) during the final demonstration of the European Union (EU) Cybercars-2 Project.

This paper describes the results of vehicle-to-vehicle (V2V) and infrastructure-to-vehicle (I2V) experiments implementing cooperative maneuvering for three different vehicles driving automatically. The cars used were cybercars from the Institut National de Recherche en Informatique et Automatique (INRIA), (France), which are fully automated road vehicles, and two mass-produced cars-one a Smart Fortwo car from TNO (Netherlands) equipped with additional actuators and sensors and the other a convertible Citroe¨n C3 from IAI (Spain) that uses sensorial information to manage the actuators. The cars communicate by a wireless mesh network over Wi-Fi using the optimized link state routing (OLSR) ad-hoc protocol. The entire communication task is embedded in a small MIPS Linux Box (4G System Cube) that is transparent for the cars. A standard framework was defined with the parameters needed to perform adaptive cruise control (ACC) and intersection maneuvers among the cars, as well as emergency stops via a signal sent by the infrastructure. The experiments were carried out in La Rochelle (France) during the final demonstration of the European Union (EU) Cybercars-2 Project.

10 pages, 15 figures.-- PACS nrs.: 73.22.-f, 75.75.+a, 72.80.Rj, 85.75.-d. ; Density-functional calculations predict half-metallicity in zigzag single-walled carbon nanotubes of finite length with the two ends saturated with hydrogen. We have analyzed the change of the α- and β-spin electronic gaps under the influence of an electric field applied along the nanotube axis. The half-metallic behavior, in which the electronic gap is zero for one spin flavor and nonzero for the other, is obtained for a critical electric field of 3.0/w V/Å, where w is the length of the nanotube. This critical field is the same as that predicted for graphene nanoribbons. By a detailed analysis of the spin structure of the ground state, we show the relevance of the edge states, electronic states spatially localized at the carbon atoms of the nanotube boundaries, on the on-set of half-metallicity, and on the magnetic properties of the finite semiconducting zigzag nanotubes. ; Research supported by MEC of Spain (Projects No. MAT2005-06544-C03-01, No. MAT2005-06544-C03-03, No. FIS2004-06490-C03-00, and MONACEM), by Junta de Castilla y León (Project No. VA039A05), by Basque Government (Project No. IE05-151) under the ETORTEK Program (NANOMAT), and by the European Network of Excellence NANOQUANTA (Grant No. NM4-CT-2004-500198). ; Peer reviewed