Resource-Efficient High-Dimensional Entanglement Detection via Symmetric Projections.

We introduce two families of criteria for detecting and quantifying the entanglement of a bipartite quantum state of arbitrary local dimension. The first is based on measurements in mutually unbiased bases and the second is based on equiangular measurements. Both criteria give a qualitative result in terms of the state's entanglement dimension and a quantitative result in terms of its fidelity with the maximally entangled state. The criteria are universally applicable since no assumptions on the state are required. Moreover, the experimenter can control the trade-off between resource-efficiency and noise-tolerance by selecting the number of measurements performed. For paradigmatic noise models, we show that only a small number of measurements are necessary to achieve nearly-optimal detection in any dimension. The number of global product projections scales only linearly in the local dimension, thus paving the way for detection and quantification of very high-dimensional entanglement.

Entanglement Detection with Imprecise Measurements.

We investigate entanglement detection when the local measurements only nearly correspond to those intended. This corresponds to a scenario in which measurement devices are not perfectly controlled, but nevertheless operate with bounded inaccuracy. We formalize this through an operational notion of inaccuracy that can be estimated directly in the lab. To demonstrate the relevance of this approach, we show that small magnitudes of inaccuracy can significantly compromise several well-known entanglement witnesses. For two arbitrary-dimensional systems, we show how to compute tight corrections to a family of standard entanglement witnesses due to any given level of measurement inaccuracy. We also develop semidefinite programming methods to bound correlations in these scenarios.

Use of serotonin reuptake inhibitors is not associated with increased bleeding after CABG.

OBJECTIVES: Selective serotonin reuptake inhibitors (SSRIs) and serotonin noradrenaline reuptake inhibitors (SNRIs) are the most commonly prescribed antidepressants worldwide. Studies suggest that SSRI/SNRIs can increase bleeding following different surgical procedures, including open heart surgery, but results are conflicting. The objective of this study was to analyse their effects on bleeding after coronary artery bypass grafting (CABG). METHODS: Of 1237 patients that underwent CABG in Iceland in 2007-2016, 97 (7.8%) used SSRIs/SNRIs preoperatively and were compared to a reference group (n = 1140). Bleeding was assessed using 24-h chest-tube output, number of RBC units transfused and reoperation for bleeding. Thirty-day mortality rates and incidence of complications were also compared. RESULTS: The two groups were comparable with respect to preoperative and operative variables, with the exception of BMI being significantly higher in the SSRI/SNRI group (30.2 vs. 28.3 kg/m2, p < 0.001). No significant differences were observed between groups in 24-h chest-tube output [815 (SSRI/SNRI) vs. 877 ml (reference), p = 0.26], number of RBC units transfused (2.2 vs. 2.2, p = 0.99) or the rate of reoperation for bleeding (4.1% vs. 6.0%, p = 0.61). The incidences of complications and 30-day mortality rate were also similar. CONCLUSIONS: Using three different criteria, preoperative use of SSRIs/SNRIs was not shown to increase bleeding after CABG. Furthermore, short-term complications as well as 30-day mortality rates did not differ from those of controls. Thus, temporary cessation of SSRI/SNRI treatment prior to CABG to decrease the risk of bleeding is unwarranted.