Technische Universität Darmstadt

About: Technische Universität Darmstadt is a education organization based out in Darmstadt, Germany. It is known for research contribution in the topics: Neutron & Finite element method. The organization has 17316 authors who have published 40619 publications receiving 937916 citations. The organization is also known as: Darmstadt University of Technology & University of Darmstadt.

The uncertainty principle in the presence of quantum memory

Abstract: The Heisenberg uncertainty principle bounds the uncertainties about the outcomes of two incompatible measurements on a quantum particle. This bound, however, changes if a memory device is involved that stores quantum information. New work now extends the uncertainty principle to include the case of quantum memories, and should provide a guide for quantum information applications.

Protozoa and plant growth: the microbial loop in soil revisited

Abstract: All nutrients that plants absorb have to pass a region of intense interactions between roots, microorganisms and animals, termed the rhizosphere. Plants allocate a great portion of their photosynthetically fixed carbon to root-infecting symbionts, such asmycorrhizal fungi; another part is released as exudates fuelling mainly free-living rhizobacteria. Rhizobacteria are strongly top-down regulated by microfaunal grazers, particularly protozoa. Consequently, beneficial effects of protozoa on plant growth have been assigned to nutrients released from consumed bacterial biomass, that is, the 'microbial loop'. In recent years however, the recognition of bacterial communication networks, the common exchange of microbial signals with roots and the fact that these signals are used to enhance the efflux of carbon from roots have revolutionized our view of rhizosphere processes. Most importantly, effects of rhizobacteria on root architecture seem to be driven in large by protozoan grazers. Protozoan effects on plant root systems stand in sharp contrast to effects of mycorrhizal fungi. Because the regulation of root architecture is a key determinant of nutrient- and water-use efficiency in plants, protozoa provide a model system that may considerably advance our understanding of the mechanisms underlying plant growth and community composition.

Digital Transformation Strategies

Abstract: In recent years, firms in almost all industries have conducted a number of initiatives to explore new digital technologies and to exploit their benefits. This frequently involves transformations of key business operations and affects products and processes, as well as organizational structures and management concepts. Companies need to establish management practices to govern these complex transformations. An important approach is to formulate a digital transformation strategy that serves as a central concept to integrate the entire coordination, prioritization, and implementation of digital transformations within a firm. The exploitation and integration of digital technologies often affect large parts of companies and even go beyond their borders, by impacting products, business processes, sales channels, and supply chains. Potential benefits of digitization are manifold and include increases in sales or productivity, innovations in value creation, as well as novel forms of interaction with customers, among others. As a result, entire business models can be reshaped or replaced (Downes and Nunes 2013). Owing to this wide scope and the far-reaching consequences, digital transformation strategies seek to coordinate and prioritize the many independent threads of digital transformation. To account for their company-spanning characteristics, digital transformation strategies cut across other business strategies and should be aligned with them (Fig. 1). While there are various concepts of IT strategies (Teubner 2013), these mostly define the current and the future operational activities, the necessary application systems and infrastructures, and the adequate organizational and financial framework for providing IT to carry out business operations within a company. Hence, IT strategies usually focus on the management of the IT infrastructure within a firm, with rather limited impact on driving innovations in business development. To some degree, this restricts the product-centric and customer-centric opportunities that arise from new digital technologies, which often cross firms’ borders. Further, IT strategies present systemcentric road maps to the future uses of technologies in a firm, but they do not necessarily account for the transformation of products, processes, and structural aspects that go along with the integration of technologies. Digital transformation strategies take on a different perspective and pursue different goals. Coming from a business-centric perspective, these strategies focus on the transformation of products, processes, and organizational aspects owing to new technologies. Their scope is more broadly designed and explicitly includes digital activities at the interface with or fully on the side of customers, such as Accepted after one revision by Prof. Dr. Sinz.

Large anomalous Hall effect driven by a nonvanishing Berry curvature in the noncolinear antiferromagnet Mn3Ge.

Abstract: It is well established that the anomalous Hall effect displayed by a ferromagnet scales with its magnetization. Therefore, an antiferromagnet that has no net magnetization should exhibit no anomalous Hall effect. We show that the noncolinear triangular antiferromagnet Mn3Ge exhibits a large anomalous Hall effect comparable to that of ferromagnetic metals; the magnitude of the anomalous conductivity is ~500 (ohm·cm)−1 at 2 K and ~50 (ohm·cm)−1 at room temperature. The angular dependence of the anomalous Hall effect measurements confirms that the small residual in-plane magnetic moment has no role in the observed effect except to control the chirality of the spin triangular structure. Our theoretical calculations demonstrate that the large anomalous Hall effect in Mn3Ge originates from a nonvanishing Berry curvature that arises from the chiral spin structure, and that also results in a large spin Hall effect of 1100 (ħ/e) (ohm·cm)−1, comparable to that of platinum. The present results pave the way toward the realization of room temperature antiferromagnetic spintronics and spin Hall effect–based data storage devices.

Resource theory of quantum states out of thermal equilibrium.

Abstract: The ideas of thermodynamics have proved fruitful in the setting of quantum information theory, in particular the notion that when the allowed transformations of a system are restricted, certain states of the system become useful resources with which one can prepare previously inaccessible states. The theory of entanglement is perhaps the best-known and most well-understood resource theory in this sense. Here, we return to the basic questions of thermodynamics using the formalism of resource theories developed in quantum information theory and show that the free energy of thermodynamics emerges naturally from the resource theory of energy-preserving transformations. Specifically, the free energy quantifies the amount of useful work which can be extracted from asymptotically many copies of a quantum system when using only reversible energy-preserving transformations and a thermal bath at fixed temperature. The free energy also quantifies the rate at which resource states can be reversibly interconverted asymptotically, provided that a sublinear amount of coherent superposition over energy levels is available, a situation analogous to the sublinear amount of classical communication required for entanglement dilution.