On the Effect of Constraint Enforcement on the Quality of Numerical Solutions in General Relativity

In Brodbeck et al 1999 it has been shown that the linearised time evolution equations of general relativity can be extended to a system whose solutions asymptotically approach solutions of the constraints. In this paper we extend the non-linear equations in similar ways and investigate the effect of various possibilities by numerical means. Although we were not able to make the constraint submanifold an attractor for all solutions of the extended system, we were able to significantly reduce the growth of the numerical violation of the constraints. Contrary to our expectations this improvement did not imply a numerical solution closer to the exact solution, and therefore did not improve the quality of the numerical solution.Comment: 14 pages, 9 figures, accepted for publication in Phys. Rev.

Unique phase diagram with narrow superconducting dome in EuFe2_2(As1−x_{1-x}Px_x)2_2 due to Eu2+^{2+} local magnetic moments

The interplay between superconductivity and Eu$^{2+}$ magnetic moments in EuFe$_2$(As$_{1-x}$P$_x$)$_2$ is studied by electrical resistivity measurements under hydrostatic pressure on $x=0.13$ and $x=0.18$ single crystals. We can map hydrostatic pressure to chemical pressure $x$ and show, that superconductivity is confined to a very narrow range $0.18\leq x \leq 0.23$ in the phase diagram, beyond which ferromagnetic (FM) Eu ordering suppresses superconductivity. The change from antiferro- to FM Eu ordering at the latter concentration coincides with a Lifshitz transition and the complete depression of iron magnetic order.Comment: 4 page

Mechanical properties and formability of en AW-7075 in cold forming processes

Due to a low density and high tensile strength, the aluminum alloy EN AW 7075 T6 offers a high lightweight potential for structural components. Since its formability is limited at room temperature in the T6 temper state, the potential of this alloy for automotive bodies is only utilizable by adapted deep drawing processes. In recent years, process chains suited for warm and hot forming have been researched and developed. However, warm and hot forming solutions require additional process steps and a complex tooling system in comparison to cold forming processes. Alternatively, the forming of such blanks at room temperature in the W temper state is favorable since conventional tools can be used. The W temper state is a heat treatment condition achieved after solution heat treatment and subsequent quenching, which is characterized by an increased ductility. However, this condition is unstable, due to the onset of natural ageing. With increasing time after the quenching step, the strength of the material increases, which leads to a reduction of formability. Another phenomenon that occurs after quenching is the Portevin Le-Chatelier effect. This effect causes the formation of flow lines during cold forming and results in a decrease of ductility. Hence, the objective of the investigations was to determine the formability of EN AW 7075 as a function of the natural ageing time after solution heat treatment and quenching. Therefore, tensile tests of various aged samples were carried out. The results show a relation of the formability to the natural ageing time and a dependency on the quenching rate. Furthermore, a heat treatment strategy for EN AW-7075 was developed, that considers manufacturing processes like the cathodic dip coating. The influence of the quenching rate, ageing time and temperature as well as the influence of temperature of the paint baking process after the cathodic dip coating were considered. Therefore, a design of experiments and tensile tests were carried out. Thus, the deep drawing of EN AW-7075 at room temperature is particularly promoted. © 2020 Published under licence by IOP Publishing Ltd

Weak continuous monitoring of a flux qubit using coplanar waveguide resonator

We study a flux qubit in a coplanar waveguide resonator by measuring transmission through the system. In our system with the flux qubit decoupled galvanically from the resonator, the intermediate coupling regime is achieved. In this regime dispersive readout is possible with weak backaction on the qubit. The detailed theoretical analysis and simulations give a good agreement with the experimental data and allow to make the qubit characterization.Comment: 4 pages, 3 figures, to be published in Phys. Rev.

Pressurized Intraperitoneal Aerosol Chemotherapy Enhanced by Electrostatic Precipitation (ePIPAC) for Patients with Peritoneal Metastases.

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is a new mode of intraperitoneal chemotherapy administration that can potentially be improved by the addition of electrostatic precipitation (ePIPAC). This study aimed to describe the procedural details of ePIPAC and to analyze its safety for patients with nonresectable peritoneal metastasis as well as their tolerance and response to this treatment. This retrospective cohort study included consecutive patients treated with ePIPAC in three centers from April 2019 to April 2020. The toxicities of each patient were assessed using the Common Terminology Criteria for Adverse Events (CTCAE). Complications were documented according to the Clavien classification. Quality of life (QoL) was assessed using EORTC-QLQ-C30, and the peritoneal regression grading score (PRGS) was used to grade histologic responses. Further surrogates for responses were the Peritoneal Cancer Index (PCI), ascites, and symptoms. Overall, 69 patients received 147 ePIPACs with oxaliplatin (n = 34) or cisplatin/doxorubicin (n = 35) mainly for colorectal (n = 25), ovarian (n = 14), and gastric (n = 13) primary cancers. Systemic chemotherapy was used in the treatment of 54 patients (76%). The median electrostatic therapy time was 12 min (range 6-30 min). The overall and major CTCAE toxicity rates were respectively 24.6% and 15.9%. The postoperative complications rate according to Clavien classification was 4.7%. The responses of 22 patients who had three or more ePIPAC treatments were evaluated as follows: PCI (16 vs 14; p = 0.4), ascites (320 vs 98 ml; p = 0.1), and PRGS (2.23 vs 1.73; p = 0.15). The complete (PRGS1) and major (PRGS2) histologic responses at the third ePIPAC were respectively 38.5% and 53.8%. Overall QoL was stable during the first ePIPACs. Repetitive ePIPACs were safe and well tolerated for patients with unresectable peritoneal metastasis

On asymptotically flat solutions of Einstein's equations periodic in time II. Spacetimes with scalar-field sources

We extend the work in our earlier article [4] to show that time-periodic, asymptotically-flat solutions of the Einstein equations analytic at scri, whose source is one of a range of scalar-field models, are necessarily stationary. We also show that, for some of these scalar-field sources, in stationary, asymptotically-flat solutions analytic at scri, the scalar field necessarily inherits the symmetry. To prove these results we investigate miscellaneous properties of massless and conformal scalar fields coupled to gravity, in particular Bondi mass and its loss.Comment: 29 pages, published in Class. Quant. Grav. Replaced. Typos corrected, version which appeared in Class. Quant.Gra

On hybrid states of two and three level atoms

We calculate atom-photon resonances in the Wigner-Weisskopf model, admitting two photons and choosing a particular coupling function. We also present a rough description of the set of resonances in a model for a three-level atom coupled to the photon field. We give a general picture of matter-field resonances these results fit into.Comment: 33 pages, 12 figure