73 research outputs found

    Clock spectroscopy of interacting bosons in deep optical lattices

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    We report on high-resolution optical spectroscopy of interacting bosonic 174^{174}Yb atoms in deep optical lattices with negligible tunneling. We prepare Mott insulator phases with singly- and doubly-occupied isolated sites and probe the atoms using an ultra-narrow "clock" transition. Atoms in singly-occupied sites undergo long-lived Rabi oscillations. Atoms in doubly-occupied sites are strongly affected by interatomic interactions, and we measure their inelastic decay rates and energy shifts. We deduce from these measurements all relevant collisional parameters involving both clock states, in particular the intra- and inter-state scattering lengths

    Non-linear Relaxation of Interacting Bosons Coherently Driven on a Narrow Optical Transition

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    We study the dynamics of a two-component Bose-Einstein condensate (BEC) of 174^{174}Yb atoms coherently driven on a narrow optical transition. The excitation transfers the BEC to a superposition of states with different internal and momentum quantum numbers. We observe a crossover with decreasing driving strength between a regime of damped oscillations, where coherent driving prevails, and an incoherent regime, where relaxation takes over. Several relaxation mechanisms are involved: inelastic losses involving two excited atoms, leading to a non-exponential decay of populations; Doppler broadening due to the finite momentum width of the BEC and inhomogeneous elastic interactions, both leading to dephasing and to damping of the oscillations. We compare our observations to a two-component Gross-Pitaevskii (GP) model that fully includes these effects. For small or moderate densities, the damping of the oscillations is mostly due to Doppler broadening. In this regime, we find excellent agreement between the model and the experimental results. For higher densities, the role of interactions increases and so does the damping rate of the oscillations. The damping in the GP model is less pronounced than in the experiment, possibly a hint for many-body effects not captured by the mean-field description.Comment: 7 pages, 4 figures; supplementary material available as ancillary fil

    Coherent Feedback Cooling of a Nanomechanical Membrane with Atomic Spins

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    Coherent feedback stabilizes a system toward a target state without the need of a measurement, thus avoiding the quantum backaction inherent to measurements. Here, we employ optical coherent feedback to remotely cool a nanomechanical membrane using atomic spins as a controller. Direct manipulation of the atoms allows us to tune from strong coupling to an overdamped regime. Making use of the full coherent control offered by our system, we perform spin-membrane state swaps combined with stroboscopic spin pumping to cool the membrane in a room-temperature environment to T=216  mK (ÂŻnm=2.3×103  phonons) in 200  Όs. We furthermore observe and study the effects of delayed feedback on the cooling performance. Starting from a cryogenically precooled membrane, this method would enable cooling of the mechanical oscillator close to its quantum mechanical ground state and the preparation of nonclassical states

    Optical coherent feedback control of a mechanical oscillator

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    Feedback is a powerful and ubiquitous technique both in classical and quantum system control. Its standard implementation relies on measuring the state of a system, processing the classical signal, and feeding it back to the system. In quantum physics, however, measurements not only read out the state of the system but also modify it irreversibly. Coherent feedback is a different kind of feedback that coherently processes and feeds back quantum signals without actually measuring the system. Here, we report on the experimental realization and the theoretical analysis of an optical coherent feedback platform to control the motional state of a nanomechanical membrane in an optical cavity. The coherent feedback loop consists of a light field interacting twice with the same mechanical mode through different cavity modes, without {performing any} measurement. Tuning the optical phase and delay of the feedback loop allows us to control the motional state of the mechanical oscillator, its resonance frequency and also its damping rate, which we use to cool the membrane close to the quantum ground state. Our theoretical analysis provides the optimal cooling conditions, showing that this new technique enables ground-state cooling. Experimentally, we show that we can cool the membrane to a state with nˉm=4.89±0.14\bar{n}_m = 4.89 \pm 0.14 phonons (480 ΌK{480}\,{\mu \mathrm{K}}) in a 20 K{20}\,\mathrm{K} environment. This lies below the theoretical limit of cavity dynamical backaction cooling in the unresolved sideband regime and is achieved with only 1%\% of the optical power required for cavity cooling. Our feedback scheme is very versatile, offering new opportunities for quantum control in a variety of optomechanical systems.Comment: 17 pages, 7 figure

    Effects of maternal modafinil treatment on fetal development and neonatal growth parameters — a multicenter case series of the European Network of Teratology Information Services (ENITS)

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    \ua9 2023 The Authors. Acta Psychiatrica Scandinavica published by John Wiley & Sons Ltd.Objective: In recent years, safety concerns about modafinil exposure during pregnancy have emerged. In particular, increased risks for major congenital anomalies (MCA) and impaired fetal growth were reported, although study results were conflicting. Our investigation aims to examine previously reported safety signals. Method: Multicenter case series based on data from 18 Teratology Information Services from 12 countries. Modafinil exposed pregnancies with an estimated date of birth before August 2019 were included in this study. For prospectively ascertained pregnancies, cumulative incidences of pregnancy outcomes, rate of nonchromosomal MCA in first trimester exposed pregnancies and percentiles of neonatal/infant weight and head circumference (HC) were calculated. Potential dose-dependent effects on fetal growth were explored by linear regression models. Retrospectively ascertained cases were screened for pattern of MCA and other adverse events. Results: One hundred and seventy-five prospectively ascertained cases were included, of which 173 were exposed at least during the first trimester. Cumulative incidences for live birth, spontaneous abortion and elective termination of pregnancy were 76.9% (95% CI, 68.0%–84.8%), 9.3% (95% CI, 5.0%–16.9%), and 13.9% (95% CI, 8.1%–23.1%), respectively. Nonchromosomal MCA was present in 3/150 live births, corresponding to an MCA rate of 2.0% (95%CI, 0.6%–6.1%), none were reported in pregnancy losses. Compared to reference standards, birth weight (BW) tended to be lower and neonatal HC to be smaller in exposed newborns (data available for 144 and 73 of 153 live births, respectively). In nonadjusted linear regression models, each 100 mg increase of average dosage per pregnancy day was associated with a decrease in standard deviation score (SDS) of −0.28 SDS (95% CI, −0.45 to −0.10) for BW and of −0.28 SDS (95% CI, −0.56 to 0.01) for HC. Screening of 22 retrospectively reported cases did not reveal any specific pattern of MCA or other adverse outcomes. Conclusion: The results do not indicate an increased risk of MCA after in utero exposure to modafinil, but a tendency toward lower BW and reduced neonatal HC. However, these findings should be regarded as preliminary. Until further studies allow for a definite conclusion, modafinil should not be used during pregnancy

    Effects of maternal modafinil treatment on fetal development and neonatal growth parameters - a multicenter case series of the European Network of Teratology Information Services (ENTIS).

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    In recent years, safety concerns about modafinil exposure during pregnancy have emerged. In particular, increased risks for major congenital anomalies (MCA) and impaired fetal growth were reported, although study results were conflicting. Our investigation aims to examine previously reported safety signals. Multicenter case series based on data from 18 Teratology Information Services from 12 countries. Modafinil exposed pregnancies with an estimated date of birth before August 2019 were included in this study. For prospectively ascertained pregnancies, cumulative incidences of pregnancy outcomes, rate of nonchromosomal MCA in first trimester exposed pregnancies and percentiles of neonatal/infant weight and head circumference (HC) were calculated. Potential dose-dependent effects on fetal growth were explored by linear regression models. Retrospectively ascertained cases were screened for pattern of MCA and other adverse events. One hundred and seventy-five prospectively ascertained cases were included, of which 173 were exposed at least during the first trimester. Cumulative incidences for live birth, spontaneous abortion and elective termination of pregnancy were 76.9% (95% CI, 68.0%-84.8%), 9.3% (95% CI, 5.0%-16.9%), and 13.9% (95% CI, 8.1%-23.1%), respectively. Nonchromosomal MCA was present in 3/150 live births, corresponding to an MCA rate of 2.0% (95%CI, 0.6%-6.1%), none were reported in pregnancy losses. Compared to reference standards, birth weight (BW) tended to be lower and neonatal HC to be smaller in exposed newborns (data available for 144 and 73 of 153 live births, respectively). In nonadjusted linear regression models, each 100 mg increase of average dosage per pregnancy day was associated with a decrease in standard deviation score (SDS) of -0.28 SDS (95% CI, -0.45 to -0.10) for BW and of -0.28 SDS (95% CI, -0.56 to 0.01) for HC. Screening of 22 retrospectively reported cases did not reveal any specific pattern of MCA or other adverse outcomes. The results do not indicate an increased risk of MCA after in utero exposure to modafinil, but a tendency toward lower BW and reduced neonatal HC. However, these findings should be regarded as preliminary. Until further studies allow for a definite conclusion, modafinil should not be used during pregnancy

    El Mirador cave (Sierra de Atapuerca, Burgos, Spain): a whole perspective

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    The archaeological site of El Mirador is located in the southern slope of the Sierra de Atapuerca. The work developed at the site is providing a substantial set of data from the Upper Palaeolithic and Early Neolithic to the Middle Bronze Age. Throughout at least about 4000 years of occupation, the cave was used for various activities, among which, burial, habitation and animal stalling. The practices related with this last use is, at the moment, the main origin of the archaeological deposits, which are mainly composed by burnt animal dung with vegetal residues, potsherds, lithics and faunal remains. In addition, it is characterized by high sedimentation rates that have enabled an individual and clear record of different episodes, providing high resolution chronological data. Due to these particularities, specific excavation methodology and interdisciplinary studies of the archaeological data have been developed in order to understand the genesis of this archaeological sequence and, at the same time, to provide information about the introduction and development of the production economy in the Submeseta Norte region.The Ministerio de Ciencia e Innovación (N_CGL2009-12703-C03-02/BTE; HAR200801984/HIST) and the Ministerio de Economía y Competitividad (CGL2012-38434-C0303; HAR2013-41197-P) and the Generalitat de Catalunya (2014SGR900; 2014SGR899) supported this research. Funding for the fieldwork came from the Consejería de Cultura y Turismo of the Junta de Castilla y León and the Atapuerca Foundation. Á. Carrancho research was funded by the Spanish Ministry of Economy and Competitiveness (MINECO) and European Regional Development Fund (FEDER) with projects CGL2012-32149 and CGL2012-3848

    Leakage of nitrous oxide emissions within the Spanish agro-food system in 1961-2009

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    Abstract In this paper we examine the trends of nitrous oxide (N2O) emissions of the Spanish agricultural sector related to national production and consumption in the 1961?2009 period.The comparison between production- and consumption-based emissions at the national level provides a complete overview of the actual impact resulting from the dietary choices of a given country and allows the evaluation of potential emission leakages. On average, 1.5 % of the new reactive nitrogen that enters Spain every year is emitted as N2O. Production- and consumption-based emissions have both significantly increased in the period studied and nowadays consumption-based emissions are 45 % higher than production-based emissions. A large proportion of the net N2O emissions associated with imported agricultural godos comes from countries that are not committers for the United Nations Framework Convention on Climate Change Kyoto Protocol Annex I. An increase in feed consumption is the main driver of the changes observed, leading to a arkable emission leakage in the Spanish agricultural sector. The complementary approach used here is essential to achieve an effective mitigation of Spanish greenhouse gas emissions
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