A composite parameterization of unitary groups, density matrices and subspaces

Unitary transformations and density matrices are central objects in quantum physics and various tasks require to introduce them in a parameterized form. In the present article we present a parameterization of the unitary group $\mathcal{U}(d)$ of arbitrary dimension $d$ which is constructed in a composite way. We show explicitly how any element of $\mathcal{U}(d)$ can be composed of matrix exponential functions of generalized anti-symmetric $\sigma$-matrices and one-dimensional projectors. The specific form makes it considerably easy to identify and discard redundant parameters in several cases. In this way, redundancy-free density matrices of arbitrary rank $k$ can be formulated. Our construction can also be used to derive an orthonormal basis of any $k$-dimensional subspaces of $\mathbb{C}^d$ with the minimal number of parameters. As an example it will be shown that this feature leads to a significant reduction of parameters in the case of investigating distillability of quantum states via lower bounds of an entanglement measure (the $m$-concurrence).Comment: 13 pages, 1 figur

Experimentally implementable criteria revealing substructures of genuine multipartite entanglement

We present a general framework that reveals substructures of genuine multipartite entanglement. Via simple inequalities it is possible to discriminate different sets of multipartite qubit states. These inequalities are beneficial regarding experimental examinations as only local measurements are required. Furthermore, the number of observables scales favorably with system size. In exemplary cases we demonstrate the noise resistance and discuss implementations.Comment: 14 pages, 4 figure

Site-selective tagging of proteins by pnictogen-mediated self-assembly

Site-selective chemical protein modification is achieved by self-assembly of a specific di-cysteine motif, trivalent pnictogens (As, Sb or Bi) and an aromatic mercaptomethyl-based probe. The strategy is demonstrated with a quaternary complex involving Zika virus protease and a lanthanide ion, enabling paramagnetic nuclear magnetic resonance spectroscopy and luminescence measurements.Financial support by the Australian Research Council is gratefully acknowledge

Bone Mineral Density and Secondary Hyperparathyroidism in Pulmonary Hypertension

BACKGROUND: Low bone mineral density (BMD) is common in chronic lung diseases and associated with reduced quality of life. Little is known about BMD in pulmonary hypertension (PH). METHODS: Steroid-naïve patients with PH (n=34; 19 idiopathic, 15 chronic thromboembolic) had BMD measured by DXA at the time of diagnostic right heart catheterization. Exercise capacity, quality of life and various parameters related to PH severity and bone metabolism were also assessed. 24 patients with left heart failure (LHF) were similarly assessed as controls. RESULTS: The prevalence of osteopenia was high both in PH (80%) and in controls with LHF (75%). Low BMD was associated with lean body mass, age, lower BMI, impaired exercise capacity and in PH with higher pulmonary vascular resistance. Serum parathyroid hormone (PTH) was elevated and considerably higher in PH than in LHF (above normal, in 55 vs 29%). Secondary hyperparathyroidism was not related to impaired renal function but possibly to low vitamin D status. CONCLUSIONS: Osteopenia is common in PH and in chronically ill patients with LHF. Osteopenia is associated with known risk factors but in PH also with disease severity. Preventive measures in an increasingly chronic ill PH population should be considered. Secondary hyperparathyroidism is highly prevalent in PH and might contribute to bone and possibly pulmonary vascular disease. Whether adequate vitamin D substitution could prevent low BMD in PH remains to be determined

Treatment of Knee Dislocation With Primary Repair and Suture Augmentation: A Viable Solution.

BACKGROUND Different surgical techniques have been described for the treatment of knee dislocation (KD). Nonoperative approaches are frequently combined with surgical reconstruction using auto- or allograft. PURPOSE To evaluate the midterm results of primary surgical repair and suture augmentation to treat KD. STUDY DESIGN Case series; Level of evidence, 4. METHODS A total of 22 patients (5 women, 17 men; mean age, 45 ± 15 years) with KD were evaluated at a mean of 49 ± 16 months after surgical treatment that included primary repair and suture augmentation. Magnetic resonance imaging, stress radiographs, and outcome scores were obtained at the follow-up. Clinical examination including hop tests and force measurements for flexion and extension was performed. RESULTS The mean difference in pre- to postinjury Tegner scores was -2 ± 1. The outcome scores showed mean values of 84 ± 15 (Lysholm), 73 ± 15 (International Knee Documentation Committee) and 65 ± 25 (Anterior Cruciate Ligament-Return to Sport after Injury scale). Compared with the uninjured knee, the range of motion of the injured knee was reduced by 21° ± 12°. Twelve patients felt fit enough to perform hop tests and showed a mean deficit of 7% ± 17%° compared with the uninjured leg. The mean force deficit was 19% ± 18% for extension and 8% ± 16% for flexion. Stress radiographs revealed an 11 ± 7-mm higher anteroposterior translation on the injured side. Four patients had secondary ligament reconstructions due to persistent instability and 7 underwent arthroscopic arthrolysis due to stiffness. A significant increase of osteoarthritis was found for the medial, lateral, and patellofemoral compartments (P = .007, .004, and .006, respectively). CONCLUSION Primary repair and suture augmentation of KD led to satisfactory clinical midterm results despite persistent radiological instability and a significant increase in osteoarthritis. This technique allows the return to activities of daily living without subjective instability in most nonathletic patients. Secondary ligament reconstructions should be performed if relevant instability persists to decrease the risk of secondary meniscal and cartilage damage

The Partisan Politics of New Social Risks in Advanced Postindustrial Democracies: Social Protection for Labor Market Outsiders

Advanced postindustrialization generates numerous challenges for the European social model. Central among these challenges is declining income, unstable employment, and inadequate training of semi- and unskilled workers. In this chapter, I assess the partisan basis of support for social policies that address the needs of these marginalized workers. I specifically consider the impacts of postindustrial cleavages among core constituencies of social democratic parties on the capacity of these parties to pursue inclusive social policies. I argue – and find support for in empirical analyses – that encompassing labor organization is the most important factor in strengthening the ability of left parties to build successful coalitions in support of outsider-friendly policies. I go beyond existing work on the topic by considering the full array of postindustrial cleavages facing left parties, by more fully elaborating why encompassing labor organization is crucial, and by considering a more complete set of measures of outsider policies than extant work. I compare my arguments and findings to important new work that stresses coalition building and partisan politics but minimizes the role of class organization

Tailored subcycle nonlinearities of ultrastrong light-matter coupling

We explore the nonlinear response of tailor-cut light-matter hybrid states in a novel regime, where both the Rabi frequency induced by a coherent driving field and the vacuum Rabi frequency set by a cavity field are comparable to the carrier frequency of light. In this previously unexplored strong-field limit of ultrastrong coupling, subcycle pump-probe and multi-wave mixing nonlinearities between different polariton states violate the normal-mode approximation while ultrastrong coupling remains intact, as confirmed by our mean-field model. We expect such custom-cut nonlinearities of hybridized elementary excitations to facilitate non-classical light sources, quantum phase transitions, or cavity chemistry with virtual photons

A habituation account of change detection in same/different judgments

We investigated the basis of change detection in a short-term priming task. In two experiments, participants were asked to indicate whether or not a target word was the same as a previously presented cue. Data from an experiment measuring magnetoencephalography failed to find different patterns for “same” and “different” responses, consistent with the claim that both arise from a common neural source, with response magnitude defining the difference between immediate novelty versus familiarity. In a behavioral experiment, we tested and confirmed the predictions of a habituation account of these judgments by comparing conditions in which the target, the cue, or neither was primed by its presentation in the previous trial. As predicted, cue-primed trials had faster response times, and target-primed trials had slower response times relative to the neither-primed baseline. These results were obtained irrespective of response repetition and stimulus–response contingencies. The behavioral and brain activity data support the view that detection of change drives performance in these tasks and that the underlying mechanism is neuronal habituation