Saturation of the Quantum Null Energy Condition in Far-From-Equilibrium Systems

The Quantum Null Energy Condition (QNEC) is a new local energy condition that a general Quantum Field Theory (QFT) is believed to satisfy, relating the classical null energy condition (NEC) to the second functional derivative of the entanglement entropy in the corresponding null direction. We present the first series of explicit computations of QNEC in a strongly coupled QFT, using holography. We consider the vacuum, thermal equilibrium, a homogeneous far-from-equilibrium quench as well as a colliding system that violates NEC. For vacuum and the thermal phase QNEC is always weaker than NEC. While for the homogeneous quench QNEC is satisfied with a finite gap, we find the interesting result that the colliding system can saturate QNEC, depending on the null direction.Comment: 5 pages, 5 figure

Stochastic Yield Catastrophes and Robustness in Self-Assembly

A guiding principle in self-assembly is that, for high production yield, nucleation of structures must be significantly slower than their growth. However, details of the mechanism that impedes nucleation are broadly considered irrelevant. Here, we analyze self-assembly into finite-sized target structures employing mathematical modeling. We investigate two key scenarios to delay nucleation: (i) by introducing a slow activation step for the assembling constituents and, (ii) by decreasing the dimerization rate. These scenarios have widely different characteristics. While the dimerization scenario exhibits robust behavior, the activation scenario is highly sensitive to demographic fluctuations. These demographic fluctuations ultimately disfavor growth compared to nucleation and can suppress yield completely. The occurrence of this stochastic yield catastrophe does not depend on model details but is generic as soon as number fluctuations between constituents are taken into account. On a broader perspective, our results reveal that stochasticity is an important limiting factor for self-assembly and that the specific implementation of the nucleation process plays a significant role in determining the yield

Exploring nonlocal observables in shock wave collisions

We study the time evolution of 2-point functions and entanglement entropy in strongly anisotropic, inhomogeneous and time-dependent N=4 super Yang-Mills theory in the large N and large 't Hooft coupling limit using AdS/CFT. On the gravity side this amounts to calculating the length of geodesics and area of extremal surfaces in the dynamical background of two colliding gravitational shockwaves, which we do numerically. We discriminate between three classes of initial conditions corresponding to wide, intermediate and narrow shocks, and show that they exhibit different phenomenology with respect to the nonlocal observables that we determine. Our results permit to use (holographic) entanglement entropy as an order parameter to distinguish between the two phases of the cross-over from the transparency to the full-stopping scenario in dynamical Yang-Mills plasma formation, which is frequently used as a toy model for heavy ion collisions. The time evolution of entanglement entropy allows to discern four regimes: highly efficient initial growth of entanglement, linear growth, (post) collisional drama and late time (polynomial) fall off. Surprisingly, we found that 2-point functions can be sensitive to the geometry inside the black hole apparent horizon, while we did not find such cases for the entanglement entropy.Comment: 28 pp, 9 figs; v2: updated references, changed color bars in Figure 2 and Figure

Beschäftigung und Arbeitslosigkeit älterer Arbeitnehmer : Eine mikroökonometrische Evaluation der Arbeitslosengeldreform von 1997

Im Jahr 1997 wurden die maximalen Anspruchsdauern auf Arbeitslosengeld für ältere Beschäftigte verkürzt. In der vorliegenden Arbeit werden die Auswirkungen dieser Reform auf Übergänge von Beschäftigung in Arbeitslosigkeit und Verweildauern in Arbeitslosigkeit dieser Gruppe untersucht. Die Analyse beruht auf der IAB-Beschäftigtenstichprobe 1975-2001, welche tagesgenaue Informationen von über einer Million sozialversicherungspflichtigen Beschäftigten und Leistungsempfängern der Bundesagentur für Arbeit umfasst. Es kann festgestellt werden, dass die Wahrscheinlichkeit, arbeitslos zu werden, bei der betrachteten Gruppe der 54-56jährigen nach der Reform abnimmt. Außerdem ist eine Verkürzung der Verweildauern in Arbeitslosigkeit nach der Reform zu beobachten. Die 54-56jährigen unterscheiden sich nach der Reform nicht mehr von der Gruppe der 52-53jährigen. Insbesondere größere Unternehmen und deren Beschäftigte nutzen die langen Anspruchsdauern auf Arbeitslosengeld zur Frühverrentung

Beschäftigung und Arbeitslosigkeit älterer Arbeitnehmer: Eine mikroökonometrische Evaluation der Arbeitslosengeldreform von 1997

Im Jahr 1997 wurden die maximalen Anspruchsdauern auf Arbeitslosengeld für ältere Beschäftigte verkürzt. In der vorliegenden Arbeit werden die Auswirkungen dieser Reform auf Übergänge von Beschäftigung in Arbeitslosigkeit und Verweildauern in Arbeitslosigkeit dieser Gruppe untersucht. Die Analyse beruht auf der IAB{Beschäftigtenstichprobe 1975-2001, welche tagesgenaue Informationen von über einer Million sozialversicherungspflichtigen Beschäftigten und Leistungsempfängern der Bundesagentur für Arbeit umfasst. Es kann festgestellt werden, dass die Wahrscheinlichkeit, arbeitslos zu werden, bei der betrachteten Gruppe der 54-56jährigen nach der Reform abnimmt. Außerdem ist eine Verkürzung der Verweildauern in Arbeitslosigkeit nach der Reform zu beobachten. Die 54-56jährigen unterscheiden sich nach der Reform nicht mehr von der Gruppe der 52-53jährigen. Insbesondere größere Unternehmen und deren Beschäftigte nutzen die langen Anspruchsdauern auf Arbeitslosengeld zur Frühverrentung. --Arbeitslosenversicherung,Frühverrentung,Administrative Daten

In-situ studies of the competitive adsorption of lubricant additives

It is known that different types of surface-affine additives (i.e. antiwear/anti-corrosion/ anti-friction) can have very different adsorption behaviour on surfaces (e.g. [1–3]). The interactions can be synergistic or antagonistic in character and influences the near-surface chemistry of the sliding surfaces and therefore also the tribological performance of the system. For wear protection additives, it is for instance known that phosphor and sulfur containing layers are formed under tribological conditions (e.g. [4,5]). In this presentation we will give an overview on an ongoing study of the adsorption of selected additives using novel in-situ approaches. The found correlations are also compared to tribological experiments in order to answer the question whether synergistic effects in adsorption also lead to synergistic effects in wear reduction

In Situ Studies on the Competitive Adsorption of Lubricant Additives

A key factor for improvement and innovation in lubricant development is a fundamental understanding of adsorption processes and competing adsorption mechanisms [1]. Many different base oils and additives, as well as various surfaces build a complex interaction space, which has been difficult to map with in-situ methods so far. Here we present a study on the adsorption of corrosion inhibitors, anti-wear additives and friction modifiers from a synthetic and a mineral base oil on metal (Fe2O3) surfaces. In order to obtain quantitative and spatial data during the adsorption process we set up a combined quartz crystal microbalance (QCM-D) and confocal scanning laser microscope (CLSM) [2]. In addition to QCM-D and CLSM, also a UHV-tribometer was used to study the performance of gas phase deposited additives films without environmental interferences. In combination with macroscopic performance tests using a “ball-on-three-plates-tribometer” and corrosion tests, the adsorption, the morphology and the mechanical properties of the additives were correlated with their performance. The multidisciplinary results provide exciting new insights into lubrication fundamentals and reveal so far undescribed phenomes and mechanisms of action. [1] J. Guegan et al. ,Friction Modifier Additives, Synergies and Antagonisms, Tribology Letters 67 (2019) [2] J. Honselmann et al., submitted, 201

Quantum Null Energy Condition and its (non)saturation in 2d CFTs

We consider the Quantum Null Energy Condition (QNEC) for holographic conformal field theories in two spacetime dimensions (CFT$_2$). We show that QNEC saturates for all states dual to vacuum solutions of AdS$_3$ Einstein gravity, including systems that are far from thermal equilibrium. If the Ryu-Takayanagi surface encounters bulk matter QNEC does not need to be saturated, whereby we give both analytical and numerical examples. In particular, for CFT$_2$ with a global quench dual to AdS$_3$-Vaidya geometries we find a curious half-saturation of QNEC for large entangling regions. We also address order one corrections from quantum backreactions of a scalar field in AdS$_3$ dual to a primary operator of dimension $h$ in a large central charge expansion and explicitly compute both, the backreacted Ryu--Takayanagi surface part and the bulk entanglement contribution to EE and QNEC. At leading order for small entangling regions the contribution from bulk EE exactly cancels the contribution from the back-reacted Ryu-Takayanagi surface, but at higher orders in the size of the region the contributions are almost equal while QNEC is not saturated. For a half-space entangling region we find that QNEC is gapped by $h/4$ in the large $h$ expansion.Comment: 37 pages, 9 figures; comments are welcom

The diversity of residential electricity demand – a comparative analysis of metered and simulated data

A comparative study between simulated residential electricity demand data and metered data from theUK Household Electricity Survey is presented. For this study, a high-resolution probabilistic model wasused to test whether this increasingly widely used modelling approach provides an adequate represen-tation of the statistical characteristics the most comprehensive dataset of metered electricity demandavailable in the UK. Both the empirical and simulated electricity consumption data have been analysedon an aggregated level, paying special attention to the mean daily load profiles, the distribution of house-holds with respect to the total annual demands, and the distributions of the annual demands of particularappliances. A thorough comparison making use of both qualitative and quantitative methods was madebetween simulated datasets and it’s metered counterparts. Significant discrepancies were found in thedistribution of households with respect to both overall electricity consumption and consumption ofindividual appliances. Parametric estimates of the distributions of metered data were obtained, and theanalytic expressions for both the density function and cumulative distribution are given. These can beincorporated into new and existent modelling frameworks, as well as used as tools for further analysis