Echo spectroscopy and Atom Optics Billiards

We discuss a recently demonstrated type of microwave spectroscopy of trapped ultra-cold atoms known as "echo spectroscopy" [M.F. Andersen et. al., Phys. Rev. Lett., in press (2002)]. Echo spectroscopy can serve as an extremely sensitive experimental tool for investigating quantum dynamics of trapped atoms even when a large number of states are thermally populated. We show numerical results for the stability of eigenstates of an atom-optics billiard of the Bunimovich type, and discuss its behavior under different types of perturbations. Finally, we propose to use special geometrical constructions to make a dephasing free dipole trap

The relational fit in organizational interventions—what can organizational research learn from research in psychotherapy?

There is a growing interest in organizational interventions (OI) aiming to increase employees’ well-being. An OI involves changes in the way work is designed, organized, and managed. Studies have shown that an OI’s positive results are increased if there is a good fit between context and intervention and between participant and intervention. In this article, we propose that a third fit—the Relational Fit (R-Fit)—also plays an important role in determining an intervention’s outcome. The R-Fit consists of factors related to (1) the employees participating in the OI, (2) the intervention facilitator, and (3) the quality of the relation between participants and the intervention facilitator. The concept of the R-Fit is inspired by research in psychotherapy documenting that participant factors, therapist factors, and the quality of the relations explain 40% of the effect of an intervention. We call attention to the importance of systematically evaluating and improving the R-Fit in OIs. This is important to enhance the positive outcomes in OIs and thereby increase both the well-being and productivity of employees. We introduce concrete measures that can be used to study and evaluate the R-Fit. This article is the first to combine knowledge from research in psychotherapy with research on OIs

Coherent manipulation of atomic qubits in optical micropotentials

We experimentally demonstrate the coherent manipulation of atomic states in far-detuned dipole traps and registers of dipole traps based on two-dimensional arrays of microlenses. By applying Rabi, Ramsey, and spin-echo techniques, we systematically investigate the dephasing mechanisms and determine the coherence time. Simultaneous Ramsey measurements in up to 16 dipole traps are performed and proves the scalability of our approach. This represents an important step in the application of scalable registers of atomic qubits for quantum information processing. In addition, this system can serve as the basis for novel atomic clocks making use of the parallel operation of a large number of individual clocks each remaining separately addressable.Comment: to be published in Appl. Phys.

Association between topical corticosteroid use and type 2 diabetes in two European population-based adult cohorts

BackgroundTopical corticosteroids (CS) are commonly used to treat inflammatory skin conditions including eczema and psoriasis. While topical CS package inserts describe hyperglycaemia and glycosuria as adverse drug reactions, it is unclear whether topical CS use in real life is also associated with an increased risk of type 2 diabetes (T2D).MethodsTwo matched case-control studies and one cohort study were conducted using routinely collected healthcare data from Denmark the UK. A total of 115,218 and 54,944 adults were identified as cases with new onset T2D in the Danish and UK case-control study, respectively. For the Danish cohort study, 2,689,473 adults were included. The main exposure was topical CS and the outcome was incident T2D.ResultsTopical CS was significantly associated with T2D in the Danish (adjusted OR 1ꞏ35; 95% CI 1ꞏ33- 1ꞏ38) and UK (adjusted OR 1ꞏ23; 95% CI 1ꞏ19-1ꞏ27) case-control studies. Individuals who were exposed to topical CS had significantly increased risk of incident T2D (adjusted HR 1ꞏ27; 95% CI 1ꞏ26-1ꞏ29). We observed significant dose-response relationships between T2D and increasing potency of topical CS in the two Danish studies. The results were consistent across all sensitivity analyses.ConclusionsWe found a positive association between topical CS prescribing and incident T2D in Danish and UK adult populations. Clinicians should be cognizant of possible diabetogenic effects of potent topical CS

Probability-fidelity tradeoffs for targeted quantum operations

We present probability-fidelity tradeoffs for a varying quantum operation with fixed input-output states and for a varying inversion of a fixed quantum operation.Comment: 6 pages, 5 figure

Generation of vortices and observation of Quantum Turbulence in an oscillating Bose-Einstein Condensate

We report on the experimental observation of vortex formation and production of tangled vortex distribution in an atomic BEC of Rb-87 atoms submitted to an external oscillatory perturbation. The oscillatory perturbations start by exciting quadrupolar and scissors modes of the condensate. Then regular vortices are observed finally evolving to a vortex tangle configuration. The vortex tangle is a signature of the presence of a turbulent regime in the cloud. We also show that this turbulent cloud has suppression of the aspect ratio inversion typically observed in quantum degenerate bosonic gases during free expansion.Comment: to appear in JLTP - QFS 200

Peatland pools are tightly coupled to the contemporary carbon cycle

Peatlands are globally important stores of soil carbon (C) formed over millennial timescales but are at risk of destabilization by human and climate disturbance. Pools are ubiquitous features of many peatlands and can contain very high concentrations of C mobilized in dissolved and particulate organic form and as the greenhouses gases carbon dioxide (CO2) and methane (CH4). The radiocarbon content (14C) of these aquatic C forms tells us whether pool C is generated by contemporary primary production or from destabilized C released from deep peat layers where it was previously stored for millennia. We present novel 14C and stable C (δ13C) isotope data from 97 aquatic samples across six peatland pool locations in the United Kingdom with a focus on dissolved and particulate organic C and dissolved CO2. Our observations cover two distinct pool types: natural peatland pools and those formed by ditch blocking efforts to rewet peatlands (restoration pools). The pools were dominated by contemporary C, with the majority of C (~50%–75%) in all forms being younger than 300 years old. Both pool types readily transform and decompose organic C in the water column and emit CO2 to the atmosphere, though mixing with the atmosphere and subsequent CO2 emissions was more evident in natural pools. Our results show little evidence of destabilization of deep, old C in natural or restoration pools, despite the presence of substantial millennial-aged C in the surrounding peat. One possible exception is CH4 ebullition (bubbling), with our observations showing that millennial-aged C can be emitted from peatland pools via this pathway. Our results suggest that restoration pools formed by ditch blocking are effective at preventing the release of deep, old C from rewetted peatlands via aquatic export

Birth weight, cardiometabolic risk factors and effect modification of physical activity in children and adolescents : pooled data from 12 international studies

Objectives: Low and high birth weight is associated with higher levels of cardiometabolic risk factors and adiposity in children and adolescents, and increases the risk of cardiovascular diseases, obesity, and early mortality later in life. Moderate-to-vigorous physical activity (MVPA) is associated with lower cardiometabolic risk factors and may mitigate the detrimental consequences of high or low birth weight. Thus, we examined whether MVPA modified the associations between birth weight and cardiometabolic risk factors in children and adolescents. Methods: We used pooled individual data from 12 cohort- or cross-sectional studies including 9,100 children and adolescents. Birth weight was measured at birth or maternally reported retrospectively. Device-measured physical activity (PA) and cardiometabolic risk factors were measured in childhood or adolescence. We tested for associations between birth weight, MVPA, and cardiometabolic risk factors using multilevel linear regression, including study as a random factor. We tested for interaction between birth weight and MVPA by introducing the interaction term in the models (birth weight x MVPA). Results: Most of the associations between birth weight (kg) and cardiometabolic risk factors were not modified by MVPA (min/day), except between birth weight and waist circumference (cm) in children (p = 0.005) and HDL-cholesterol (mmol/l) in adolescents (p = 0.040). Sensitivity analyses suggested that some of the associations were modified by VPA, i.e., the associations between birth weight and diastolic blood pressure (mmHg) in children (p = 0.009) and LDL- cholesterol (mmol/l) (p = 0.009) and triglycerides (mmol/l) in adolescents (p = 0.028). Conclusion: MVPA appears not to consistently modify the associations between low birth weight and cardiometabolic risk. In contrast, MVPA may mitigate the association between higher birth weight and higher waist circumference in children. MVPA is consistently associated with a lower cardiometabolic risk across the birth weight spectrum. Optimal prenatal growth and subsequent PA are both important in relation to cardiometabolic health in children and adolescents.publishedVersio

Optical symmetries and anisotropic transport in high-Tc superconductors

A simple symmetry analysis of in-plane and out-of-plane transport in a family of high temperature superconductors is presented. It is shown that generalized scaling relations exist between the low frequency electronic Raman response and the low frequency in-plane and out-of-plane conductivities in both the normal and superconducting states of the cuprates. Specifically, for both the normal and superconducting state, the temperature dependence of the low frequency $B_{1g}$ Raman slope scales with the $c-$axis conductivity, while the $B_{2g}$ Raman slope scales with the in-plane conductivity. Comparison with experiments in the normal state of Bi-2212 and Y-123 imply that the nodal transport is largely doping independent and metallic, while transport near the BZ axes is governed by a quantum critical point near doping $p\sim 0.22$ holes per CuO$_{2}$ plaquette. Important differences for La-214 are discussed. It is also shown that the $c-$ axis conductivity rise for $T\ll T_{c}$ is a consequence of partial conservation of in-plane momentum for out-of-plane transport.Comment: 16 pages, 8 Figures (3 pages added, new discussion on pseudogap and charge ordering in La214