Geodesic distances on density matrices

We find an upper bound for geodesic distances associated to monotone Riemannian metrics on positive definite matrices and density matrices.Comment: 10 page

A priori probability that a qubit-qutrit pair is separable

We extend to arbitrarily coupled pairs of qubits (two-state quantum systems) and qutrits (three-state quantum systems) our earlier study (quant-ph/0207181), which was concerned with the simplest instance of entangled quantum systems, pairs of qubits. As in that analysis -- again on the basis of numerical (quasi-Monte Carlo) integration results, but now in a still higher-dimensional space (35-d vs. 15-d) -- we examine a conjecture that the Bures/SD (statistical distinguishability) probability that arbitrarily paired qubits and qutrits are separable (unentangled) has a simple exact value, u/(v Pi^3)= >.00124706, where u = 2^20 3^3 5 7 and v = 19 23 29 31 37 41 43 (the product of consecutive primes). This is considerably less than the conjectured value of the Bures/SD probability, 8/(11 Pi^2) = 0736881, in the qubit-qubit case. Both of these conjectures, in turn, rely upon ones to the effect that the SD volumes of separable states assume certain remarkable forms, involving "primorial" numbers. We also estimate the SD area of the boundary of separable qubit-qutrit states, and provide preliminary calculations of the Bures/SD probability of separability in the general qubit-qubit-qubit and qutrit-qutrit cases.Comment: 9 pages, 3 figures, 2 tables, LaTeX, we utilize recent exact computations of Sommers and Zyczkowski (quant-ph/0304041) of "the Bures volume of mixed quantum states" to refine our conjecture

Pyeloplasty in children: is there a difference in patients with or without crossing lower pole vessel?

Introduction: Most of the children with hydronephrosis do not require any surgical intervention. However, in individual cases, irreversible loss of renal function can develop. Predictive criteria have been proven ineffective so far in determining in which children obstruction will lead to renal damage. The aim of our retrospective study was to determine the role of a crossing lower pole vessel (CV) in children undergoing pyeloplasty. Materials and methods: Between 1996 and 2003, 137 patients (age between 6weeks and 16years) with unilateral ureteropelvic junction obstruction and no associated urological pathologies underwent Anderson-Hynes dismembered pyeloplasty. A total of 112 patients were evaluated with complete data. One of the following criteria was considered to be indication for surgery in children with grade 4 hydronephrosis: differential renal function (DRF) 10% and washout patterns II or III b according to O'Reilly. We looked at the age during surgery and the kind of presentation. DRF was measured using diuretic renography preoperatively and 1year postoperatively. A postoperative change in DRF of group A (children without CV, n=84) was compared to that in group B (children with CV, n=28). Results: Median age at the time of surgery was 5months in group A compared to 23months in group B. Only in 21.4% of the children with CV compared to 60.7% without CV hydronephrosis was diagnosed by ultrasound examination antenatally. We found a preoperative DRF of 42.4%±11.2 SD in group A, and of 38.9%±11.7 SD in group B. The percentage of postoperative improvement was 3.3% in group A and 15.4% in group B. Conclusions: Children with ureteropelvic junction obstruction and CV received a delayed surgical treatment and showed a greater reduction in differential renal function preoperatively, in contrast to patients without CV. Our data show that CV is a risk factor for deterioration of renal function in children with hydronephrosis and we advocate for an early pyeloplasty in these children, especially if they have a high-grade dilatation and equivocal washout patterns in diuretic renographies. Further prospective studies are necessary in order to understand the natural history of CV and to reveal the importance of the crossing lower pole vessel as a structural anomaly lacking maturatio

Sauerstoff-Aufnahme von Humanplasma nach Zugabe von Kobalt

Peer Reviewe

Transport limits in defect-engineered LaAlO3/SrTiO3 bilayers

The electrical properties of the metallic interface in LaAlO3/SrTiO3 (LAO/STO) bilayers are investigated with focus on the role of cationic defects in thin film STO. Systematic growth-control of the STO thin film cation stoichiometry (defect-engineering) yields a relation between cationic defects in the STO layer and electronic properties of the bilayer-interface. Hall measurements reveal a stoichiometry-effect primarily on the electron mobility. The results indicate an enhancement of scattering processes in as-grown non-stoichiometric samples indicating an increased density of defects. Furthermore, we discuss the thermodynamic processes and defect-exchange reactions at the LAO/STO-bilayer interface determined in high temperature equilibrium. By quenching defined defect states from high temperature equilibrium, we finally connect equilibrium thermodynamics with room temperature transport. The results are consistent with the defect-chemistry model suggested for LAO/STO interfaces. Moreover, they reveal an additional healing process of extended defects in thin film STO

Bures volume of the set of mixed quantum states

We compute the volume of the N^2-1 dimensional set M_N of density matrices of size N with respect to the Bures measure and show that it is equal to that of a N^2-1 dimensional hyper-halfsphere of radius 1/2. For N=2 we obtain the volume of the Uhlmann 3-D hemisphere, embedded in R^4. We find also the area of the boundary of the set M_N and obtain analogous results for the smaller set of all real density matrices. An explicit formula for the Bures-Hall normalization constants is derived for an arbitrary N.Comment: 15 revtex pages, 2 figures in .eps; ver. 3, Eq. (4.19) correcte

Hall Normalization Constants for the Bures Volumes of the n-State Quantum Systems

We report the results of certain integrations of quantum-theoretic interest, relying, in this regard, upon recently developed parameterizations of Boya et al of the n x n density matrices, in terms of squared components of the unit (n-1)-sphere and the n x n unitary matrices. Firstly, we express the normalized volume elements of the Bures (minimal monotone) metric for n = 2 and 3, obtaining thereby "Bures prior probability distributions" over the two- and three-state systems. Then, as an essential first step in extending these results to n > 3, we determine that the "Hall normalization constant" (C_{n}) for the marginal Bures prior probability distribution over the (n-1)-dimensional simplex of the n eigenvalues of the n x n density matrices is, for n = 4, equal to 71680/pi^2. Since we also find that C_{3} = 35/pi, it follows that C_{4} is simply equal to 2^{11} C_{3}/pi. (C_{2} itself is known to equal 2/pi.) The constant C_{5} is also found. It too is associated with a remarkably simple decompositon, involving the product of the eight consecutive prime numbers from 2 to 23. We also preliminarily investigate several cases, n > 5, with the use of quasi-Monte Carlo integration. We hope that the various analyses reported will prove useful in deriving a general formula (which evidence suggests will involve the Bernoulli numbers) for the Hall normalization constant for arbitrary n. This would have diverse applications, including quantum inference and universal quantum coding.Comment: 14 pages, LaTeX, 6 postscript figures. Revised version to appear in J. Phys. A. We make a few slight changes from the previous version, but also add a subsection (III G) in which several variations of the basic problem are newly studied. Rather strong evidence is adduced that the Hall constants are related to partial sums of denominators of the even-indexed Bernoulli numbers, although a general formula is still lackin

A 52-Week Study of Olanzapine with a Randomized Behavioral Weight Counseling Intervention in Adolescents with Schizophrenia or Bipolar I Disorder

Objectives: To evaluate the 52-week safety/tolerability of oral olanzapine for adolescents with schizophrenia or bipolar mania and compare effectiveness of a standard versus intense behavioral weight intervention in mitigating risk of weight gain. Methods: Patients 13?17 years old with schizophrenia (Brief Psychiatric Rating Scale for Children [BPRS-C] total score >30; item score ≥3 for hallucinations, delusions, or peculiar fantasies) or bipolar I disorder (manic or mixed episode; Young Mania Rating Scale [YMRS] total score ≥15) received open-label olanzapine (2.5?20?mg/day) and were randomized to standard (n?=?102; a single weight counseling session) or intense (n?=?101; weight counseling at each study visit) weight intervention. The primary outcome measure was mean change in body mass index (BMI) from baseline to 52 weeks using mixed-model repeated measures. Symptomatology was also assessed. Results: No statistically significant differences between groups were observed in mean baseline-to-52-week change in BMI (standard: +3.6?kg/m2; intense: +2.8?kg/m2; p?=?0.150) or weight (standard: +12.1?kg; intense: +9.6?kg; p?=?0.148). Percentage of patients at endpoint who had gained ≥15% of their baseline weight was 40% for the standard group and 31% for the intense group (p?=?0.187). Safety/tolerability results were generally consistent with those of previous olanzapine studies in adolescents, with the most notable exception being the finding of a mean decrease in prolactin. On symptomatology measures, patients with schizophrenia had a mean baseline-to-52-week change in BPRS-C of ?32.5 (standard deviation [SD]?=?10.8), and patients with bipolar disorder had a mean change in YMRS of ?16.7 (SD?=?8.9), with clinically and statistically significant improvement starting at 3?4 days for each. Conclusions: Long-term weight gain was high in both groups, with no statistically significant differences between the standard or intense behavioral weight interventions in BMI or weight. Safety, tolerability, and effectiveness findings were generally consistent with the known profile of olanzapine in adolescents.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140324/1/cap.2016.0010.pd