Fast adiabatic transport of single laser-cooled 9Be+ ions in a cryogenic Penning trap stack

High precision mass and g-factor measurements in Penning traps have enabled groundbreaking tests of fundamental physics. The most advanced setups use multi-trap methods, which employ transport of particles between specialized trap zones. Present developments focused on the implementation of sympathetic laser cooling will enable significantly shorter duty cycles and better accuracies in many of these scenarios. To take full advantage of these increased capabilities, we implement fast adiabatic transport concepts developed in the context of trapped-ion quantum information processing in a cryogenic Penning trap system. We show adiabatic transport of a single 9Be+ ion initially cooled to 2 mK over a 2.2-cm distance within 15 ms and with less than 10 mK energy gain at a peak velocity of 3 m/s. These results represent an important step towards the implementation of quantum logic spectroscopy in the (anti-)proton system. Applying these developments to other multi-trap systems has the potential to considerably increase the data-sampling rate in these experiments

Optical stimulated-Raman sideband spectroscopy of a single 9Be+ ion in a Penning trap

We demonstrate optical sideband spectroscopy of a single 9Be+ ion in a cryogenic 5 tesla Penning trap using two-photon stimulated-Raman transitions between the two Zeeman sublevels of the 1s22s ground state manifold. By applying two complementary coupling schemes, we accurately measure Raman resonances with and without contributions from motional sidebands. From the latter we obtain an axial sideband spectrum with an effective mode temperature of (3.1±0.4) mK. These results are a key step for quantum logic operations in Penning traps, applicable to high-precision matter-antimatter comparison tests in the baryonic sector of the standard model

Resolved-sideband cooling of a single 9^9Be+^+ ion in a Penning trap

Manipulating individual trapped ions at the single quantum level has become standard practice in radio-frequency ion traps, enabling applications from quantum information processing to precision metrology. The key ingredient is ground-state cooling of the particle's motion through resolved-sideband laser cooling. Ultra-high-presicion experiments using Penning ion traps will greatly benefit from the reduction of systematic errors offered by full motional control, with applications to atomic masses and $g$-factor measurements, determinations of fundamental constants or related tests of fundamental physics. In addition, it will allow to implement quantum logic spectroscopy, a technique that has enabled a new class of precision measurements in radio-frequency ion traps. Here we demonstrate resolved-sideband laser cooling of the axial motion of a single $^9$Be$^+$ ion in a cryogenic 5 Tesla Penning trap system using a two-photon stimulated-Raman process, reaching a mean phonon number of $\bar{n}_z = 0.10(4)$. This is a fundamental step in the implementation of quantum logic spectroscopy for matter-antimatter comparison tests in the baryonic sector of the Standard Model and a key step towards improved precision experiments in Penning traps operating at the quantum limit.Comment: 6 pages, 5 figure

Quantum logic inspired techniques for spacetime-symmetry tests with (anti-)protons

Cosmological observations as well as theoretical approaches to physics beyond the standard model provide strong motivations for experimental tests of fundamental symmetries, such as CPT invariance. In this context, the availability of cold baryonic antimatter at CERN has opened an avenue for ultrahigh-precision comparisons of protons and antiprotons in Penning traps. This work discusses an experimental method inspired by quantum logic techniques that will improve particle localization and readout speed in such experiments. The method allows for sympathetic cooling of the (anti-)proton to its quantum-mechanical ground state as well as the readout of its spin alignment, replacing the commonly used continuous Stern–Gerlach effect. Both of these features are achieved through coupling to a laser-cooled 'logic' ion co-trapped in a double-well potential. This technique will boost the measurement sampling rate and will thus provide results with lower statistical uncertainty, contributing to stringent searches for time dependent variations in the data. Such measurements ultimately yield extremely high sensitivities to CPT violating coefficients acting on baryons in the standard-model extension, will allow the exploration of previously unmeasured types of symmetry violations, and will enable antimatter-based axion-like dark matter searches with improved mass resolution

Clinical and virological characteristics of hospitalised COVID-19 patients in a German tertiary care centre during the first wave of the SARS-CoV-2 pandemic: a prospective observational study

Purpose: Adequate patient allocation is pivotal for optimal resource management in strained healthcare systems, and requires detailed knowledge of clinical and virological disease trajectories. The purpose of this work was to identify risk factors associated with need for invasive mechanical ventilation (IMV), to analyse viral kinetics in patients with and without IMV and to provide a comprehensive description of clinical course. Methods: A cohort of 168 hospitalised adult COVID-19 patients enrolled in a prospective observational study at a large European tertiary care centre was analysed. Results: Forty-four per cent (71/161) of patients required invasive mechanical ventilation (IMV). Shorter duration of symptoms before admission (aOR 1.22 per day less, 95% CI 1.10-1.37, p < 0.01) and history of hypertension (aOR 5.55, 95% CI 2.00-16.82, p < 0.01) were associated with need for IMV. Patients on IMV had higher maximal concentrations, slower decline rates, and longer shedding of SARS-CoV-2 than non-IMV patients (33 days, IQR 26-46.75, vs 18 days, IQR 16-46.75, respectively, p < 0.01). Median duration of hospitalisation was 9 days (IQR 6-15.5) for non-IMV and 49.5 days (IQR 36.8-82.5) for IMV patients. Conclusions: Our results indicate a short duration of symptoms before admission as a risk factor for severe disease that merits further investigation and different viral load kinetics in severely affected patients. Median duration of hospitalisation of IMV patients was longer than described for acute respiratory distress syndrome unrelated to COVID-19

Uso de plantas com finalidade medicinal por pessoas vivendo com HIV/ AIDS em terapia antirretroviral

Este foi um estudo observacional, transversal analítico realizado em ambulatório de referência do Estado do Maranhão-Brasil, no período de maio de 2009 a fevereiro de 2010, com o objetivo de estudar o uso de plantas com finalidade medicinal entre pessoas vivendo com HIV/AIDS, em uso de antirretrovirais. Um total de 339 pessoas respondeu um questionário abordando o uso de plantas e características demográficas, socioeconômicas, comportamentais, relacionadas à soropositividade e ao uso de antirretrovirais. A prevalência de utilização de plantas foi de 34,81%. As mais utilizadas foram: Turnera ulmifolia (12,09%); Melissa officinalis (10,62%); Plectranthus barbatus (7,67%); Cymbopogan citratus (capim limão) (4,72%) e Mentha spp. (hortelã) (2,36%). A maioria das pessoas (96,61%) referiu melhora após a utilização. Um percentual de 75,42% dos usuários de plantas não informou essa prática ao médico. Entre os que informaram o uso, 55,17% afirmaram que o médico estava de acordo e somente uma pessoa foi orientada a interromper o uso (3,45%). Apenas um médico (3,45%) indicou o uso de plantas. A análise ajustada evidenciou diferença para uso de plantas em relação ao sexo feminino (RP=1,58, 95% IC 1,15-2,15 p 0,004) e à orientação sexual do tipo homossexual (RP=0,63 IC 0,44-0,90 p 0,012). Este estudo aponta para a necessidade de melhor diálogo entre médico e pacientes sobre o uso de plantas com finalidade medicinal, alertando sobre possíveis perigos quando associados aos antirretrovirais, especialmente entre usuários do sexo feminino ou com prática do tipo homossexual.It is an observational, analytic study, developed at a hospital in Maranhao-Brazil, from May-2009 to February-2010. The objective was to study the use of plants with medicinal purpose in people living with HIV/AIDS and using retroviral therapy. A total of 339 (three hundred and thirty-nine) people answered a questionnaire about the use of plants and demographic, socioeconomic, behavioral characteristics, including those related to HIV status and use of antiretroviral therapy The prevalence of the use of plants with medicinal purpose was 34,81%. The most often used were: Turnera ulmifolia (chanana) (12,09%), Melissa officinalis (erva cidreira,) (10,62%), Plectranthus barbatus (boldo) (7,67%), Cymbopogan citratus (capim limão) (4,72%) and Mentha spp. (hortelã) (2,36%). Most people interviewed (96,61%) reported improvement after use. A rate of 75,42% of the plant users had not reported their practice to a medical doctor. Among respondents who reported use, 55.17% said their doctor agreed to it, and only one person was advised to discontinue the use (3,45%); only one doctor (3,45%) indicated the use of plants. Multivariate analysis showed differences for the use of plants in relation to gender (female PR= 1,58, 95% CI 1,15 - 2,15 p 0,004) and homosexual practices (PR= 0,63, CI 0,44 - 0,90 p 0,012). This study highlights the need for a better dialogue between doctors and patients about the use of plants with medicinal purposes, and warns about possible dangers when they are combined with antirretroviral therapy, particularly between female and homossexual users

Characterisation of an experiment for sympathetic cooling and coupling of ions in a cryogenic Penning trap

The comparison of the g-factors of the proton and the antiproton is a stringent test of CPT invariance. The state-of-the-art method for the determination of the (anti-)proton's g-factor is the application of the continuous Stern-Gerlach effect. With this method, precisions in the low parts per billion regime could be achieved. However, preparation times for cold enough particles are on the order of minutes to hours. The implementation of sympathetic cooling using a co-trapped atomic ion could lead to preparation times in the milliseconds regime. Furthermore, the applicability of sympathetic cooling would enable an alternative readout scheme using quantum logic methods. This thesis presents a Penning trap system that is designed for ground state cooling, adiabatic transport, and motional coupling of single 9Be+ ions. It has been built in a modular manner, giving the option of adapting it for motional coupling and sympathetic cooling of single (anti-)protons. In the course of this work, the prerequisites for motional coupling of 9Be+ ions have been fulfilled: A cloud of 9Be+ ions was cooled to a temperature of 1.7~mK applying Doppler cooling. The achieved temperature is about three times the Doppler limit which is 0.5~mK for beryllium ions. Furthermore, a scheme for reproducible loading of the trap and reducing the particle number was developed. Finally, first transport in our apparatus was demonstrated with clouds of beryllium ions. The method used for that is directly applicable to single ions. The results of this work pave the way towards adiabatic transport of single 9Be+ ions, which is crucial for sympathetic cooling of (anti-)protons in a double-well potential as well as for implementing quantum logic spectroscopy with single (anti-)protons

NAO related small pelagic fisheries fluctuations off Morocco and Senegal

Publicado