Co-tunneling current and shot noise in quantum dots

We derive general expressions for the current and shot noise, taking into account non-Markovian memory effects. In generalization of previous approaches our theory is valid for arbitrary Coulomb interaction and coupling strength and is applicable to quantum dots and more complex systems like molecules. A diagrammatic expansion up to second-order in the coupling strength, taking into account co-tunneling processes, allows for a study of transport in a regime relevant to many experiments. As an example, we consider a single-level quantum dot, focusing on the Coulomb-blockade regime. We find super-Poissonian shot noise due to spin-flip co-tunneling processes at an energy scale different from the one expected from first-order calculations, with a sensitive dependence on the coupling strength.Comment: 4 pages, three figures, submitted to PR

Technologie-Roadmap Lithium-Ionen-Batterien 2030

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International competitiveness of the european economy with regard to the EU state aid policy: the case of nanoelectronics. Summary

The domestic growth of high-tech industries is seen as central to future economic development in many countries. In this context, companies are often granted high levels of state support (e.g. through subsidies or tax breaks) to promote growth and employment in these promising sectors or fields of technology. In Europe, however, state support opportunities are regulated by EU state aid control. The aim is to reduce state aid from member states in order to promote European integration and free competition within Europe. State aid is only granted by EU member states under certain conditions Subject and objective of the project The impact of EU state aid control on national policy-making in the field of nanoelectronics is being discussed particularly intensively. Nanoelectronics is regarded as an important cross-sectional technology or industry whose components are in demand and used in numerous user industries. In particular, the construction of new production facilities is massively supported by some states, and at the same time production sites are increasingly being established outside Europe. The effects of EU state aid control on the competitiveness of Europe and its member states such as Germany are generally complex and above all indirect. They depend centrally on the development of other factors in the innovation system (e.g. demand, domestic establishment of user industries), the interaction of these factors, the use of complementary policy instruments and the extent of public support in non-European countries. The Innovation Report therefore examines the following research questions: Which factors influence the attractiveness of individual countries as locations for nanoelectronics? How should the current competitiveness in Germany and Europe be assessed? What consequences would a loss of production capacities have for the entire "nanoelectronics innovation system"? To what extent is there a situation in the field of nanoelectronics that justifies state aid? How can a sustainable funding policy be implemented, especially under the given conditions of limited state aid possibilities? To what extent can the example of nanoelectronics be transferred to other technologies and sectors

Super-poissonian noise, negative differential conductance, and relaxation effects in transport through molecules, quantum dots and nanotubes

We consider charge transport through a nanoscopic object, e.g. single molecules, short nanotubes, or quantum dots, that is weakly coupled to metallic electrodes. We account for several levels of the molecule/quantum dot with level-dependent coupling strengths, and allow for relaxation of the excited states. The current-voltage characteristics as well as the current noise are calculated within first-order perturbation expansion in the coupling strengths. For the case of asymmetric coupling to the leads we predict negative-differential-conductance accompanied with super-poissonian noise. Both effects are destroyed by fast relaxation processes. The non-monotonic behavior of the shot noise as a function of bias and relaxation rate reflects the details of the electronic structure and level-dependent coupling strengths.Comment: 8 pages, 7 figures, submitted to Phys. Rev. B, added reference

Barriers to the establishment of new key technologies. Summary

Germany is considered innovative and, in a global comparison, excellent in basic research and technology development. Germany is strong in its traditional markets, such as mechanical and vehicle engineering or electrical engineering. However, Germany also has problems when it comes to the rapid and broad implementation of the innovative ideas and results of research and development in concrete applications, especially for the establishment of new, future-oriented key technologies. The diffusion of applications resulting from new key technologies on the market also often confronts companies and entrepreneurs with blockades that are difficult or almost impossible to overcome. Subject and objective of the study The objective of the project "Blockades in the Establishment of New Key Technologies" was to investigate the existing innovation barriers in Germany that block or impede the establishment of new key technologies and the creation of German lead markets or the replacement of traditional export technologies by new key technologies. However, factors that have a particularly beneficial effect should also be identified. On this basis, specific technologies or markets were identified where Germany has not yet exhausted its diffusion and market potential or has been particularly successful in doing so. Finally, by analysing the factors to which these deficits or successes could be attributed, possibilities for political influence were elicited that could contribute to the removal of existing blockades and the promotion of positive factors. The project used a combined approach of a cross-technology innovation system analysis and three technology-specific, in-depth case studies to investigate specific key technologies. The innovation system approach was based on a comprehensive literature and data analysis and provided a research grid for the three case studies. In doing so, the innovation system analysis primarily aimed at capturing and structuring the central inhibiting and facilitating factors, which were specifically investigated and evaluated in the case studies. The case studies selected were Nanoelectronics as a cross-sectional technology, wind energy as an application technology, MP3 players and mini beamers as applications and product innovations respectively. Within the framework of these case studies, several expert interviews were conducted with relevant stakeholders in each case, as well as a workshop in the German Bundestag in Berlin with representatives from science, business and politics. The results of the three case studies were harmonised via the research grid in order to finally compare the identified blockages and derived measures or options for action on a generalised basis. In doing so, blockades were related to suitable measures and possible contributions for involved actors were identified, by means of which the dismantling of existing blockades and the establishment of new key technologies could be supported

Electric mobility concepts and their significance for the economy, society and the environment. Summary

Electromobility is currently fuelling hopes worldwide for a more sustainable development of the transport sector. The TAB report analyses ecological, economic and social aspects of electromobility for Germany and compares them with those of conventional automobiles. The ecological balance is particularly in favour of electromobility when low- or zero-CO2 energy sources are used, because in addition to greenhouse gases, other pollutant emissions are also significantly reduced. The economic analysis examines economic efficiency, implications for the automotive value chain and jobs, and the supply of critical raw materials. With a future stronger diffusion of electromobility in Germany, slightly positive effects on the employment situation and the development of GDP are expected. The social implications are examined on the basis of acceptance, user behaviour, traffic noise and accidents. The report shows that a positive user acceptance can be achieved with a wider range of models while complying with common quality and comfort standards as well as extended test possibilities, but also by reducing acquisition costs, a wider range of user-friendly mobility and business models and, last but not least, a transparent positive environmental balance. On the basis of the analyses, critical aspects and potentials of electric mobility are discussed, leading to policy-relevant conclusions and options for action

Wettbewerbsfähigkeit der europäischen Wirtschaft im Hinblick auf die EU-Beihilfepolitik - am Beispiel der Nanoelektronik. Innovationsreport

Das inländische Wachstum von Hightech-Branchen wird in vielen Ländern als zentral für die zukünftige wirtschaftliche Entwicklung angesehen. Dabei werden Unternehmen häufig hohe staatliche Unterstützungen (z. B. durch Subventionierung oder Steuervergünstigungen) gewährt, um Wachstum und Beschäftigung in diesen zukunftsträchtigen Sektoren oder Technikfeldern zu fördern. In Europa werden die staatlichen Unterstützungsmöglichkeiten jedoch durch die EU-Beihilfekontrolle reguliert. Ziel ist die Reduzierung staatlicher Beihilfen der Mitgliedstaaten, um die europäische Integration und den freien Wettbewerb innerhalb Europas voranzutreiben. Nur unter bestimmten Voraussetzungen werden staatliche Beihilfen von EU-Mitgliedstaaten gewährt Gegenstand und Ziel der Untersuchung Besonders intensiv werden die Auswirkungen der EU-Beihilfekontrolle auf die nationale Politiksteuerung im Bereich der Nanoelektronik diskutiert. Die Nanoelektronik gilt als wichtige Querschnittstechnologie bzw. Branche, deren Komponenten in zahlreichen Anwenderbranchen nachgefragt und eingesetzt werden. Vor allem der Bau von neuen Produktionsstätten wird massiv von einigen Staaten unterstützt, und zugleich werden Produktionsstandorte zunehmend außerhalb Europas aufgebaut. Die Auswirkungen der EU-Beihilfekontrolle auf die Wettbewerbsfähigkeit Europas bzw. ihrer Mitgliedsländer wie Deutschland sind insgesamt vielschichtig und vor allem indirekter Natur. Sie hängen zentral von der Ausprägung anderer Faktoren im Innovationssystem (z. B. Nachfrage, inländische Ansiedlungen von Anwenderbranchen), dem Zusammenspiel dieser Faktoren, der Nutzung komplementärer, politischer Instrumente sowie dem Ausmaß öffentlicher Unterstützung in außereuropäischen Staaten, ab. Der Innovationsreport untersucht daher folgende Forschungsfragen: Welche Faktoren beeinflussen die Standortattraktivität einzelner Länder in der Nanoelektronik? Wie ist die aktuelle Wettbewerbsfähigkeit am Standort Deutschland und in Europa zu beurteilen? Welche Folgen hätte ein Verlust der Produktionskapazitäten für das gesamte »Innovationssystem Nanoelektronik«? Inwieweit besteht im Bereich der Nanoelektronik eine Situation, die staatliche Beihilfe rechtfertigen lässt? Wie kann eine nachhaltige Förderpolitik gerade unter den gegebenen Bedingungen der eingeschränkten staatlichen Beihilfemöglichkeiten erfolgen? Inwieweit lässt sich das Beispiel der Nanoelektronik auf andere Technologien und Branchen übertragen? INHALT ZUSAMMENFASSUNG 5 I. EINLEITUNG 19 1. Zielsetzung 19 2. Aufbau des Berichts 21 3. Quellen und Methoden 22 II. WETTBEWERBSFÄHIGKEIT DER EUROPÄISCHEN WIRTSCHAFT IN HIGHTECHBRANCHEN MIT FOKUS AUF DIE NANOELEKTRONIK 27 1. Europäische Wettbewerbsfähigkeit in Hightechbranchen 27 1.1 Bedeutung der Hightechbranchen und internationaler Wettbewerbsvergleich 29 1.2 Aktuelle Krisensituation und Ausblick 34 2. Entwicklung in der Nanoelektronik und Vergleich der internationalen Wettbewerbsfähigkeit führender Länder 37 2.1 Nanoelektronik: Definition, Bereiche und Bedeutung 37 2.2 Produktions- und Beschäftigungsentwicklung 42 3. Einflussfaktoren für die Innovations- und Wettbewerbsfähigkeit Europas in der Nanoelektronik 48 3.1 Wissensbasis 48 3.2 Wissenstransfer und Vernetzung 52 3.3 Industrielle Akteure und Produktion 61 3.4 Nachfrage und Rahmenbedingungen 70 4. Zwischenfazit 75 III. POLITIKMASSNAHMEN IN FÜHRENDEN LÄNDERN IN DER NANOELEKTRONIK 77 1. Förderung der Nanoelektronik in Europa 78 1.1 Ansätze und Strukturen der europäischen Forschungspolitik 78 1.2 Deutschland 85 1.3 Frankreich 94 2. Globale Förderung in der Nanoelektronik 100 2.1 Taiwan 100 2.2 China 106 2.3 Japan 113 2.4 Südkorea 117 2.5 USA 121 3. Zwischenfazit 127 IV. EU-BEIHILFENKONTROLLE: ZIELE, RECHTFERTIGUNG UND BEDEUTUNG FÜR DIE NANOELEKTRONIK 131 1. Rechtfertigungsgründe für staatliche Beihilfen sowie deren Kontrolle 131 1.1 Rechtfertigungsgründe für staatliche Beihilfen mit Fokus auf die Nanoelektronik 131 1.2 Risiken staatlicher Eingriffe und Gründe für eine strikte EU-Beihilfenkontrolle 147 2. Charakterisierung der EU-Beihilfenkontrolle 152 2.1 Intention der Beihilfenkontrolle und Bedeutung für die europäische Integration 152 2.2 Darstellung der Beihilfenkontrolle 153 2.3 Verfahren der Beihilfenkontrolle und Verteilung der Kompetenzen 159 2.4 Weitere internationale Regelungen 161 3. Empirische Analyse der staatlichen Beihilfen in der Europäischen Union 163 3.1 Entwicklung der allgemeinen staatlichen Beihilfen 163 3.2 Bedeutung der Beihilfenkontrolle für die Nanoelektronik 166 4. Zwischenfazit 175 V. SCHLUSSFOLGERUNGEN UND HANDLUNGSOPTIONEN 179 1. Einleitende Bemerkungen 179 2. Allgemeine Handlungsoptionen 182 3. Rahmensetzende Politik 187 4. Aktive sektorale Technologie-/Industriepolitik 195 5. Zusammenfassung der Handlungsoptionen 206 VI. LITERATUR 209 VII. ANHANG 223 1. Tabellenverzeichnis 223 2. Abbildungsverzeichnis 224 3. Übersichten 22