Correlations and enlarged superconducting phase of tt-J⊥J_\perp chains of ultracold molecules on optical lattices

We compute physical properties across the phase diagram of the $t$-$J_\perp$ chain with long-range dipolar interactions, which describe ultracold polar molecules on optical lattices. Our results obtained by the density-matrix renormalization group (DMRG) indicate that superconductivity is enhanced when the Ising component $J_z$ of the spin-spin interaction and the charge component $V$ are tuned to zero, and even further by the long-range dipolar interactions. At low densities, a substantially larger spin gap is obtained. We provide evidence that long-range interactions lead to algebraically decaying correlation functions despite the presence of a gap. Although this has recently been observed in other long-range interacting spin and fermion models, the correlations in our case have the peculiar property of having a small and continuously varying exponent. We construct simple analytic models and arguments to understand the most salient features.Comment: published version with minor modification

Functional Renormalization Group for Non-Equilibrium Quantum Many-Body Problems

Das Ziel dieser Arbeit ist die Anwendung der funktionalen Renormierungsgruppe (FRG) auf Nichtsgleichgewichtsprobleme. Zu diesem Zweck formulieren wir die FRG-Gleichungen im Rahmen des Keldysh-Formalismus, der das Standardverfahren darstellt, um Nichtgleichgewichtssysteme zu beschreiben. Als einfachsten nichttrivialen Fall, um die Leistungsfähigkeit und die Grenzen der Nichtgleichgewichts-FRG zu testen, wählen wir das Störstellenandersonsmodell (SIAM). Das SIAM stellt das Standardmodell für Korrelationseffekte in Festkörpern dar und steht im Mittelpunkt einer langen Reihe von theoretischen und experimentellen Untersuchungen. Insbesondere kann das SIAM als Standardmodell zur Beschreibung der physikalischen Eigenschaften von Nanostrukturen, wie z.B. Quantenpunkten, betrachtet werden. Diese Strukturen sind interessant, weil sie unkonventionelle physikalische Effekte wie single-electron-tunneling zeigen. Außerdem können Quantenpunkte neue Aussichten für künftige Generationen von elektronischen Schaltungen eröffnen. Nach einer allgemeinen Einführung in die mesoskopischen Systeme und die Grundlagen des Keldysh-Verfahrens leiten wir die FRG-Gleichungen für den Nichtgleichgewichtsfall her und führen die Unterschiede zwischen den Gleichgewichts- und Nichtgleichgewichtsschemata aus. Die FRG kann verwendet werden, um fermionische, und bosonische Systeme zu beschreiben, sowohl im stationären als auch im nichtstationären Fall. Im zweiten Anteil dieser Arbeit untersuchen wir die Transportseigenschaften von Quantenpunkten in verschiedenen physikalischen Situationen. Als Erstes analysieren wir den "einfachsten" Fall, nämlich die Anwendung der Nichtgleichgewichts-FRG auf das SIAM mit endlicher Bias-Spannung V_B bei T=0. Hier können wir das Verfahren durch einen Vergleich mit den exakten Resultaten im Limes V_B = 0 prüfen. Als nächsten Schritt führen wir die Temperatur T und ein äußeres magnetisches Feld B ein, um die Wirkung dieser zwei Parameter auf die Transportseigenschaften zu berücksichtigen. Der Vergleich mit bekannten Resultaten für den Fall V_B = 0 erlaubt uns den Anwendungsbereich der Nichtsgleichgewichts-FRG und die Genauigkeit unserer Ergebnisse zu überprüfen.The aim of this work is the extension of the functional renormalization group (FRG) formalism to treat non-equilibrium situations. To this end, we reformulate the FRG equations in terms of the Keldysh method which is the standard technique to treat systems out of equilibrium. As simplest non-trivial application to test the potential and weakness of the non-equilibrium FRG we choose the single impurity Anderson model (SIAM). This model represents the paradigm for correlation effects in condensed matter physics and it is at the heart of a large range of experimental and theoretical investigations. In particular, the SIAM can be considered as the standard model for describing the physical properties of certain nanostructures and mesoscopic systems, such as quantum dots. These devices are interesting because they show fancy physical effects such as single electron tunneling and they could open new perspectives for future generations of electronic devices. After a general introduction to mesoscopic systems and the basics of the Keldysh technique, we derive the FRG equations for treating non-equilibrium situations and we point out the differences between equilibrium and non-equilibrium FRG schemes. The FRG can be adopted to describe both fermionic and bosonic systems and, at least formally, time-dependent situations as well as the stationary case. In the second part of this work we analyze the transport properties of quantum dots in several physical situations. First, we study the ""easiest"" case, namely we apply the non-equilibrium FRG formalism to the SIAM with finite bias voltage V_B in the stationary state at T=0. Here, we can test the technique by comparing it to available exact results for the linear response regime V_B = 0. As next step we switch on an external magnetic field B and the temperature T in order to observe the effect of these two parameters on the transport properties of a quantum dot. The comparison to known results for V_B = 0 allows us to critically survey the range of applicability of the Non-equilibrium FRG and the accuracy of the results

Addenda and Erratum to: Characteristic directions of closed planar motions

In a previous paper [2], some properties of closed planar motions were investigated. The focus was on three aspects: the area enclosed by the paths of points, the polar moment of inertia and the natural average of a path. These three mathematical objects were shown to be interrelated. For reasons of completeness, we now add some historical references which relate the problem considered to that of mechanical integrators eg. polarplanimeter. In this communication, we introduce a fourth related entity, which is analogous to the action in theoretical mechanics. The relationship of action to the entities discussed in our previous article is given by a spatial invariant. Then, we add some properties of the double hinge, in order to clarify the example given in the previous paper. Finally, we correct a sign error which appeared in [2]. In the Appendix (see Supplementary Material, Wiley online library), we present a general construction for spatial invariants. (C) 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei

A functional renormalization group approach to non-equilibrium properties of mesoscopic interacting quantum systems

We present an extension of the concepts of the functional renormalization group approach to quantum many-body problems in non-equilibrium situations. The approach is completely general and allows calculations for both stationary and time-dependent situations. As a specific example we study the stationary state transport through a quantum dot with local Coulomb correlations. We discuss the influence of finite bias voltage and temperature on the current and conductance. (C) 2009 Elsevier B.V. All rights reserved

Single-pill fixed-dose drug combinations to reduce blood pressure: the right pill for the right patient

Arterial hypertension is one of the major causes of cardiovascular morbidity and mortality worldwide. Effective and sustained reduction in blood pressure is essential to reduce individual cardiovascular risk. In daily clinical practice, single-pill fixed-dose combinations of different drug classes are important therapeutic resources that could improve both treatment adherence and cardiovascular risk management by targeting distinct pathophysiological mechanisms. The aim of this practical narrative review is to help physicians choosing the right single-pill fixed-dose combination for the right patient in the daily clinical practice, based on the individual clinical phenotype and cardiovascular risk profile

Physiologically shaped knee arthroplasty induces natural roll-back

After total knee replacement the persistence of pain represents a significant problem. In this study, a novel knee arthroplasty (Aequos G1 knee arthroplasty) is investigated that was designed to replicate main features of human knee morphology to reduce the periodically occurring pain after knee replacement. Previous work showed theoretically that this arthroplasty design may reconstruct the four-bar linkage mechanism as it occurs in human knee by contriving a convex lateral tibial compartment and a sagittal offset of the centre of the medial and lateral femur condyles - inducing a roll-back mechanism as it exists in human. The aim of this study was to determine whether this potential roll-back mechanism can be confirmed by in-vivo measurements. This retrospective study showed that the patellar tendon angle decreases during flexion of 0.21 degrees per degree of flexion on average in the 16 knees studied. This amount is similar to physiological knee kinematics and in contrast to existing results in the literature after implantation of conventional total knee replacements which lack physiological knee kinematics. The results suggest that physiological motion after implantation of the Aequos G1 knee arthroplasty occurs during loaded motion up to approximately 45 degrees knee flexion

Validation of the Novel Web-Based Application HUMTELEMED for a Comprehensive Assessment of Cardiovascular Risk Based on the 2021 European Society of Cardiology Guidelines

Background and aims: SCORE2/SCORE2-OP cardiovascular risk (CVR) charts and online calculators do not apply to patients with comorbidities, target organ damage, or atherosclerotic cardiovascular disease, for whom the assessment relies on the conventional consultation of the 2021 ESC guidelines (qualitative approach). To simplify the CVR evaluation, we developed an integrated multi-language and free-to-use web application. This study assessed the agreement between the conventional method versus our web app. Methods: A cross-sectional study was carried out on 1306 consecutive patients aged 40+ years referred to our center for the diagnosis and management of hypertension and dyslipidemia. Two double-blind operators performed the CVR assessment and classified each patient into low–moderate-, high-, and very-high-risk categories by using the conventional method (SCORE2/SCORE2-OP charts and consultation of the 2021 ESC guidelines) and the web app. The Kappa statistics were used to compare the two methods. Results: The mean age was 60.3 ± 11.9 years, with male prevalence (51.4%). Patients in primary prevention were 77.0%. According to the SCORE2/SCORE2-OP charts and 2021 ESC guideline consultation, the CVR was low–moderate in 18.6% (n° 243), high in 36.8% (n° 480), and very high in 44.6% (n° 583). According to the web app, individual CVR was low–moderate in 19.5% (n° 255), high in 35.4% (n° 462), and very high in 45.1% (n° 589). The two methods strongly agreed (Kappa = 0.960, p Conclusions: our application has excellent reliability in a broad “real life” population and may help non-expert users and busy clinicians to assess individual CVR appropriately, representing a free-to-use, simple, time-sparing and widely available alternative to the conventional CVR evaluation using SCORE2/SCORE2-OP and 2021 ESC guideline charts