Violation of the Cauchy-Schwarz inequality with matter waves

The Cauchy-Schwarz (CS) inequality -- one of the most widely used and important inequalities in mathematics -- can be formulated as an upper bound to the strength of correlations between classically fluctuating quantities. Quantum mechanical correlations can, however, exceed classical bounds.Here we realize four-wave mixing of atomic matter waves using colliding Bose-Einstein condensates, and demonstrate the violation of a multimode CS inequality for atom number correlations in opposite zones of the collision halo. The correlated atoms have large spatial separations and therefore open new opportunities for extending fundamental quantum-nonlocality tests to ensembles of massive particles.Comment: Final published version (with minor changes). 5 pages, 3 figures, plus Supplementary Materia

The High-Acceptance Dielectron Spectrometer HADES

HADES is a versatile magnetic spectrometer aimed at studying dielectron production in pion, proton and heavy-ion induced collisions. Its main features include a ring imaging gas Cherenkov detector for electron-hadron discrimination, a tracking system consisting of a set of 6 superconducting coils producing a toroidal field and drift chambers and a multiplicity and electron trigger array for additional electron-hadron discrimination and event characterization. A two-stage trigger system enhances events containing electrons. The physics program is focused on the investigation of hadron properties in nuclei and in the hot and dense hadronic matter. The detector system is characterized by an 85% azimuthal coverage over a polar angle interval from 18 to 85 degree, a single electron efficiency of 50% and a vector meson mass resolution of 2.5%. Identification of pions, kaons and protons is achieved combining time-of-flight and energy loss measurements over a large momentum range. This paper describes the main features and the performance of the detector system

Mean field effects on the scattered atoms in condensate collisions

We consider the collision of two Bose Einstein condensates at supersonic velocities and focus on the halo of scattered atoms. This halo is the most important feature for experiments and is also an excellent testing ground for various theoretical approaches. In particular we find that the typical reduced Bogoliubov description, commonly used, is often not accurate in the region of parameters where experiments are performed. Surprisingly, besides the halo pair creation terms, one should take into account the evolving mean field of the remaining condensate and on-condensate pair creation. We present examples where the difference is clearly seen, and where the reduced description still holds.Comment: 6 pages, 4 figure

HADES experiment: di-lepton spectroscopy in p + p (2.2 GeV) and C+C (1 and 2 A GeV) collisions

The HADES (High Acceptance Di-Electron Spectrometer) is a tool designed for lepton pair (e+e−) spectroscopy in pion, proton and heavy ion induced reactions in the 1–2AGeV energy range. One of the goals of the HADES experiment is to study in-medium modifications of hadron properties like effective masses, decay widths, electromagnetic form factors etc. Such effects can be probed with vector mesons ( ρ,ω,ɸ ) decaying into e+e− channel. The identification of vector mesons by means of a HADES spectrometer is based on invariant mass reconstruction of e+e− pairs. The combined information from all spectrometer sub-detectors is used to reconstruct the di-lepton signal. The recent results from 2.2GeV p + p, 1AGeV and 2AGeV C+C experiments are presented.Diaz Medina, Jose, [email protected]

Study of e+,e− production in elementary and nuclear collisions near the production threshold with HADES

HADES is a second generation experiment designed to study dielectron production in proton, pion, and heavy ion induced reactions at the GSI accelerator facility in Darmstadt. The physics programme of HADES is focused on in-medium properties of the light vector mesons. In this contribution we present status of the HADES experiment, demonstrate its capability to identify rare dielectron signal, show first experimental results obtained from C+C reactions at 2 A GeV and shortly discuss physics programme of up-coming experimental runs. © 2004 Elsevier B.V. All rights reserved. 53 1 49 58 Cited By :1

Cross-Sensor Feedback Stabilization of an Emulated Quantum Spin Gyroscope

Quantum sensors, such as the nitrogen-vacancy (N-V) color center in diamond, are known for their exquisite sensitivity but their performance over time is subject to degradation by environmental noise. To improve the long-term robustness of a quantum sensor, here we realize an integrated combinatorial spin sensor in the same micrometer-scale footprint, which exploits two different spin sensitivities to distinct physical quantities to stabilize one spin sensor with local information collected in real time via the second sensor. We show that we can use the electronic spins of a large ensemble of N-V centers as sensors of the local magnetic field fluctuations, affecting both spin sensors, in order to stabilize the output signal of interleaved Ramsey sequences performed on the N14 nuclear spin. An envisioned application of such a device is to sense rotation rates with a stability of several days, allowing navigation with limited or no requirement for geolocalization. Our results would enable stable rotation sensing for over several hours, which already reflects better performance than microelectromechanical systems (MEMS) gyroscopes of comparable sensitivity and size.United States. Office of Naval Research (Award N00014-14-1-0804)United States. Army Research Office (Award W911NF-11-1-0400

Electrochemical Methods for Lithium Recovery: A Comprehensive and Critical Review

Due to the ubiquitous presence of lithium‐ion batteries in portable applications, and their implementation in the transportation and large‐scale energy sectors, the future cost and availability of lithium is currently under debate. Lithium demand is expected to grow in the near future, up to 900 ktons per year in 2025. Lithium utilization would depend on a strong increase in production. However, the currently most extended lithium extraction method, the lime‐soda evaporation process, requires a period of time in the range of 1–2 years and depends on weather conditions. The actual global production of lithium by this technology will soon be far exceeded by market demand. Alternative production methods have recently attracted great attention. Among them, electrochemical lithium recovery, based on electrochemical ion‐pumping technology, offers higher capacity production, it does not require the use of chemicals for the regeneration of the materials, reduces the consumption of water and the production of chemical wastes, and allows the production rate to be controlled, attending to the market demand. Here, this technology is analyzed with a special focus on the methodology, materials employed, and reactor designs. The state‐of‐the‐art is reevaluated from a critical perspective and the viability of the different proposed methodologies analyzed.The financial support of the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska‐Curie (Grant Agreement No. 665919) are gratefully acknowledged. The authors acknowledge the free distribution of VESTA software.Peer reviewe

In vivo translational start site selection on leaderless mRNA transcribed from the Streptomyces fradiae aph gene.

The message of the Streptomyces fradiae aph gene lacks a leader sequence and therefore is translated in the absence of a conventional Shine-Dalgarno interaction between mRNA and 30S ribosomal subunits. Insertion mutations generating short leaders of 2 or 4 nucleotides on the 5' end of the aph transcript reduced translational efficiency. A 4-base leader (5'-AUGC-3') placing a potential out-of-frame start codon immediately upstream of the aph coding sequence prevented detectable translation in the aph reading frame. The upstream AUG in this mutant was able to drive the expression of a reporter gene in a translational fusion vector, implying that this start codon was utilized in favor of the downstream AUG. Additional leaders (5'-AUAUGC-3' or 5'-CAUAUGC-3') placing 2 or 3 nucleotides 5' to the upstream AUG relieved this apparent discrimination, permitting translation of the APH protein from the downstream AUG. These results suggest that the position of a start codon with respect to the 5' terminus of aph mRNA is a determinant of translational efficiency and start site selection