Efficient current-induced domain-wall displacement SrRuO3

We demonstrate current-induced displacement of ferromagnetic domain walls in sub-micrometer fabricated patterns of SrRuO3 films. The displacement, monitored by measuring the extraordinary Hall effect, is induced at zero applied magnetic field and its direction is reversed when the current is reversed. We find that current density in the range of 10^9 - 10^10 A/m^2 is sufficient for domain-wall displacement when the depinning field varies between 50 to 500 Oe. These results indicate relatively high efficiency of the current in displacing domain walls which we believe is related to the narrow width ~3 nm of domain walls in this compound

Emulating the one-dimensional Fermi-Hubbard model by a double chain of qubits

The Jordan-Wigner transformation maps a one-dimensional (1D) spin- 1 / 2 system onto a fermionic model without spin degree of freedom. A double chain of quantum bits with X X and Z Z couplings of neighboring qubits along and between the chains, respectively, can be mapped on a spin-full 1D Fermi-Hubbard model. The qubit system can thus be used to emulate the quantum properties of this model. We analyze physical implementations of such analog quantum simulators, including one based on transmon qubits, where the Z Z interaction arises due to an inductive coupling and the X X interaction due to a capacitive interaction. We propose protocols to gain confidence in the results of the simulation through measurements of local operators

Offensive Mitbestimmung: Stärkung der betrieblichen Mitbestimmung

Es ist an der Zeit, die strategische Debatte über Mitbestimmung, Demokratie und Beteiligung selbstbewusst und offensiv in die Öffentlichkeit zu tragen. Das vorliegende Memorandum zur Weiterentwicklung der betrieblichen Mitbestimmung ist ein Schritt in diese Richtung, den wir im Rahmen der "Offensive Mitbestimmung" gehen. Gemeinsam getragen vom DGB und seinen Mitgliedsgewerkschaften, gestützt auf Forschung und externen Sachverstand, werden wir aus wissenschaftlichen Erkenntnissen und praktischen Erfahrungen, politische Forderungen für die Zukunft der betrieblichen Mitbestimmung ableiten. Das Memorandum versteht sich als Work in Progress, denn die praktische und gesetzliche Entwicklung der betrieblichen Mitbestimmung kann nie abgeschlossen sein. Sie muss ständig mit der betrieblichen Wirklichkeit von Arbeit Schritt halten und sich neuen Herausforderungen stellen. Wir laden die Akteure der Mitbestimmung zur Diskussion ein, um ge-meinsam die Mitbestimmung zu stärken und sie auf der Höhe der Zeit zu halten

The Emerging Role of E-Agribusiness - State of the Art and Perspectives in Germany

The aim of this paper is to describe and analyse the emerging role of electronic agribusiness and the corresponding consequences in Germany. The study was carried out as a consecutive step by step procedure, including empirical surveys in farm and agribusiness small and medium size enterprises, accompanied by case studies in agribusiness firms, and a technology assessment expert survey. The results indicate that internet penetration on farm and agribusiness enterprise levels is rather high, but currently information and communication activities clearly dominate over commercial business activities. The case studies show that the internal communication changed significantly due to the implementation of internet applications like emailing, newsgroups, periodic information sheets and video-conferencing. Additionally, external communication changes according to the availability of internet features, e.g. suppliers of parts established internet networks for co-ordinated sales activities. The technology assessment expert survey indicates a gain in importance for pre- and after-sales services and communication activities by using internet technologies. Conclusions are - among others - an increasing importance of e-agribusiness and correspondingly an acceleration of structural change, but low or no expected effects on ecological parameters and on the labour market.E-Business, E-Agribusiness, Technology assessment, Survey, Germany, Agribusiness,

Effects of gate errors in digital quantum simulations of fermionic systems

Digital quantum simulations offer exciting perspectives for the study of fermionic systems such as molecules or lattice models. However, with quantum error correction still being out of reach with present-day technology, a non-vanishing error rate is inevitable. We study the influence of gate errors on simulations of the Trotterized time evolution of the quantum system with focus on the fermionic Hubbard model. Specifically, we consider the effect of stochastic over-rotations in the applied gates. Depending on the particular algorithm implemented such gate errors may lead to a time evolution that corresponds to a disordered fermionic system, or they may correspond to unphysical errors, e.g., violate particle number conservation. We substantiate our analysis by numerical simulations of model systems. In addition we establish the relation between the gate fidelity and the strength of the over-rotations in a Trotterized quantum simulation. Based on this we provide estimates for the maximum number of Trotter steps which can be performed with sufficient accuracy for a given algorithm. This in turn implies, apart from obvious limitations on the maximum time of the simulation, also limits on the system size which can be handled.Comment: 12 pages, 12 figure