52 research outputs found

    Qubit interference at avoided crossings: The role of driving shape and bath coupling

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    We derive the structure of the Landau-Zener-St\"uckelberg-Majorana (LZSM) interference pattern for a qubit that experiences quantum dissipation and is additionally subjected to time-periodic but otherwise general driving. A spin-boson Hamiltonian serves as model which we treat with a Bloch-Redfield master equation in Floquet basis. It predicts a peak structure that depends sensitively on the operator through which the qubit couples to the bath. The Fourier transforms of the LZSM patterns exhibit arc structures which reflect the shape of the driving. These features are captured by an effective time-independent Bloch equation which provides an analytical solution. Moreover, we determine the decay of these arcs as a function of dissipation strength and temperature.Comment: 10 pages, 6 figures, submitted to PR

    Entanglement creation in a quantum dot-nanocavity system

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    We explore the possibility to entangle an excitonic two-level system in a semiconductor quantum dot (QD) with a cavity defined on a photonic crystal by sweeping the cavity frequency across its resonance with the exciton transition. The dynamic cavity detuning is established by a radio frequency surface acoustic wave (SAW). It induces Landau-Zener (LZ) transitions between the excitonic and the photonic degrees of freedom and thereby creates a superposition state. We optimize this scheme by using tailored Fourier-synthesized SAW pulses with up to five harmonics. The theoretical study is performed with a master equation approach for present state-of-the-art setups. Assuming experimentally demonstrated system parameters, we demonstrate that the composed pulses increase both the maximum entanglement and its persistence. The latter is only limited by the dominant dephasing mechanism; i.e., the photon loss from the cavity.Comment: 7 pages, 4 figure

    Employing Circuit QED to Measure Nonequilibrium Work Fluctuations

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    We study an interferometric method for the measurement of the statistics of work performed on a driven quantum system, which has been put forward recently [Dorner et al., Phys. Rev. Lett. 110 230601 (2013), Mazzola et al., Phys. Rev. Lett. 110 230602 (2013)]. The method allows replacing two projective measurements of the energy of the driven system with qubit tomography of an ancilla that is appropriately coupled to it. We highlight that this method could be employed to obtain the work statistics of closed as well as open driven system, even in the strongly dissipative regime. We then illustrate an implementation of the method in a circuit QED set-up, which allows one to experimentally obtain the work statistics of a parametrically driven harmonic oscillator. Our implementation is an extension of the original method, in which two ancilla-qubits are employed and the work statistics is retrieved through two-qubit state tomography. Our simulations demonstrate the experimental feasibility.Comment: 18 pages, 4 figures. Accepted for publication in New Journal of Physics in the Focus issue on Quantum Microwave Field Effects in Superconducting Circuit

    Tiotropium in asthmatic adolescents symptomatic despite inhaled corticosteroids: A randomised dose-ranging study

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    SummaryIntroductionTiotropium, a once-daily long-acting anticholinergic agent, has been shown to be an efficacious and safe add-on treatment for adults with symptomatic asthma, despite treatment with inhaled corticosteroids (ICS). A large proportion of asthmatic adolescents have symptomatic disease despite a wide range of therapeutic options. We investigated the efficacy and safety of three doses of tiotropium, administered in the evening (via Respimat® SoftMist™ inhaler), versus placebo in asthmatic adolescents symptomatic despite ICS treatment.MethodsThis randomised, double-blind, placebo-controlled, incomplete crossover study evaluated once-daily tiotropium 5 μg, 2.5 μg and 1.25 μg versus placebo in three 4-week treatment periods. Primary efficacy end point was change in peak forced expiratory volume in 1 s within 3 h post-dose from baseline (peak FEV1(0–3h)).ResultsFrom 139 enrolled patients, 105 were randomised to receive one of four treatment sequences. Peak FEV1(0–3h) response for tiotropium 5 μg was significantly greater versus placebo (p = 0.0043). Trough FEV1 responses were significantly greater for tiotropium 5 μg (p < 0.00001) and 1.25 μg (p = 0.0134) versus placebo, but not for 2.5 μg (p = 0.0975), while FEV1 area under the curve(0–3h) responses were significant for all doses (p = 0.00001–0.0398). Overall incidence of adverse events was balanced across treatment groups, with no dose-dependent observations. The majority of adverse events were mild to moderate in intensity.ConclusionThis first study of tiotropium in adolescents with symptomatic asthma demonstrates that tiotropium is well tolerated and efficacious as add-on to maintenance treatment with ICS.ClinicalTrials.gov identifier; NCT01122680

    Efficacy of once-daily tiotropium Respimat in adults with asthma at GINA Steps 2-5

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    Tiotropium Respimat is an efficacious add-on to maintenance treatment in patients with symptomatic asthma. Currently, the Global Initiative for Asthma (GINA) strategy recommends tiotropium for patients at Steps 4–5. To assess the clinical benefits of tiotropium Respimat across asthma severities, GINA Steps 2–5, a post hoc analysis of five double-blind trials (12–48-weeks; patients aged 18–75 years) investigated the effect of tiotropium Respimat, 5 μg or 2.5 μg, versus placebo, on peak forced expiratory volume in 1 s (FEV1) within 3 h post-dose (FEV1(0–3h)) response, and Asthma Control Questionnaire-7 (ACQ-7) responder rate. GINA step grouping was based on patients’ background treatment regimen. Baseline characteristics of patients (N = 2926) were balanced between treatments. Tiotropium Respimat showed consistent improvements in lung function across GINA steps; placebo-corrected peak FEV1(0–3h) improvements after tiotropium Respimat 5 μg and 2.5 μg were: Step 2 (Week 8), 135 mL (95% confidence interval: 84, 187) and 155 mL (103, 206); Step 3 (Week 24), 187 mL (139, 235) and 235 mL (187, 283); Step 4 (Week 24), 111 mL (63, 159) and 181 mL (35, 326); Step 5 (Week 24; 5 μg only), 164 mL (5, 323). Asthma control improved with tiotropium Respimat versus placebo, showing statistical significance (nominal P value) with tiotropium Respimat 5 μg at Step 4 (odds ratio 1.36 [1.03, 1.78]). Safety profiles were similar between treatments. In conclusion, tiotropium Respimat add-on therapy improves lung function, and may improve asthma control, in adults across disease severities.</p

    Dissecting the action of an evolutionary conserved non-coding region on renin promoter activity

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    Elucidating the mechanisms of the human transcriptional regulatory network is a major challenge of the post-genomic era. One important aspect is the identification and functional analysis of regulatory elements in non-coding DNA. Genomic sequence comparisons between related species can guide the discovery of cis-regulatory sequences. Using this technique, we identify a conserved region CNSmd of ∼775 bp in size, ∼14 kb upstream of the renin gene. Renin plays a pivotal role for mammalian blood pressure regulation and electrolyte balance. To analyse the cis-regulatory role of this region in detail, we perform 132 combinatorial reporter gene assays in an in vitro Calu-6 cell line model. To dissect the role of individual subregions, we fit several mathematical models to the experimental data. We show that a multiplicative switch model fits best the experimental data and that one subregion has a dominant effect on promoter activity. Mapping of the sub-sequences on phylogenetic conservation data reveals that the dominant regulatory region is the one with the highest multi-species conservation score

    Conflicts of Interest in the Assessment of Chemicals, Waste, and Pollution

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    Pollution by chemicals and waste impacts human and ecosystem health on regional, national, and global scales, resulting, together with climate change and biodiversity loss, in a triple planetary crisis. Consequently, in 2022, countries agreed to establish an intergovernmental science–policy panel (SPP) on chemicals, waste, and pollution prevention, complementary to the existing intergovernmental science–policy bodies on climate change and biodiversity. To ensure the SPP’s success, it is imperative to protect it from conflicts of interest (COI). Here, we (i) define and review the implications of COI, and its relevance for the management of chemicals, waste, and pollution; (ii) summarize established tactics to manufacture doubt in favor of vested interests, i.e., to counter scientific evidence and/or to promote misleading narratives favorable to financial interests; and (iii) illustrate these with selected examples. This analysis leads to a review of arguments for and against chemical industry representation in the SPP’s work. We further (iv) rebut an assertion voiced by some that the chemical industry should be directly involved in the panel’s work because it possesses data on chemicals essential for the panel’s activities. Finally, (v) we present steps that should be taken to prevent the detrimental impacts of COI in the work of the SPP. In particular, we propose to include an independent auditor’s role in the SPP to ensure that participation and processes follow clear COI rules. Among others, the auditor should evaluate the content of the assessments produced to ensure unbiased representation of information that underpins the SPP’s activities

    The fundamental left-right asymmetry in the Germanic verb cluster

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    Cinque (2005, 2009, 2014a) observes that there is an asymmetry in the possible ordering of dependents of a lexical head before versus after the head. A reflection on some of the concepts needed to develop Cinque’s ideas into a theory of neutral word order reveals that dependents need to be treated separately by class. The resulting system is applied to the problem of word order in the Germanic verb cluster. It is shown that there is an extremely close match between theoretically derived expectations for clusters made up of auxiliaries, modals, causative ‘let’, a main verb, and verbal particles. The facts point to the action of Cinque’s fundamental left-right asymmetry in language in the realm of the verb cluster. At the same time, not all verb clusters fall under Cinque’s generalization, which, therefore, argues against treating all cases of restructuring uniformly
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