Transfer of a quantum state from a photonic qubit to a gate-defined quantum dot

Interconnecting well-functioning, scalable stationary qubits and photonic qubits could substantially advance quantum communication applications and serve to link future quantum processors. Here, we present two protocols for transferring the state of a photonic qubit to a single-spin and to a two-spin qubit hosted in gate-defined quantum dots (GDQD). Both protocols are based on using a localized exciton as intermediary between the photonic and the spin qubit. We use effective Hamiltonian models to describe the hybrid systems formed by the the exciton and the GDQDs and apply simple but realistic noise models to analyze the viability of the proposed protocols. Using realistic parameters, we find that the protocols can be completed with a success probability ranging between 85-97%

Die SPD von 1984 bis 2017: Verlust der sozialen Basis und der Wandel von Wahlentscheidungen. Eine quantitative Analyse aus makrosoziologischer und sozialpsychologischer Perspektive.

Die vorliegende Dissertation betrachtet die Entwicklung von Parteiidentifikationen (PI) mit der SPD in verschiedenen sozialen Gruppen sowie von Einstellungen zur SPD im Hinblick auf die Wahlentscheidung über den Zeitraum von 1984 bis 2017. Die Entwicklung der Partei wird aus zwei Perspektiven der Wahlforschung betrachtet: Zum einen aus der makrosoziologischen Perspektive („Cleavage-Modell“), zum anderen aus der sozialpsychologischen Perspektive („Michigan-Modell“). Das erste zentrale Ergebnis ist, dass die soziostrukturelle Prägung der SPD-Anhängerschaft durch formal Niedriggebildete und Arbeiter über den Beobachtungszeitraum praktisch vollständig aufgelöst wurde. Während in den 1980ern SPD-Bindungen bei Arbeitern und Niedriggebildeten noch deutlich häufiger vorkamen als in anderen Gruppen, ist das am Ende der Beobachtungsreihe im Jahr 2017 nicht mehr der Fall. Der zweite Ergebnisteil beschäftigt sich mit der Rolle von Einstellungen zur SPD bei der Wahlentscheidung bei den Bundestagswahlen von 1994 bis 2017. Je nach Wahljahr erhöhte eine SPD-Bindung die Wahrscheinlichkeit für eine entsprechende Wahl um 60 bis 80 Prozentpunkte. Die Verluste, die die Partei im Vergleich zu den 1990ern erlebte, können also teilweise durch den Rückgang an Parteibindungen an die SPD erklärt werden. Dies konnte noch für einige Wahlen durch starke Kandidateneffekte, kombiniert mit einem populären Amtsinhaber kompensiert werden, ab 2009 fielen solche kurzfristig wirksamen Effekte allerdings weg.This dissertation examines party identification (PI) for the SPD among different social groups as well as attitudes towards the party with regard to vote choice over the course of several decades. It thus follows the party’s development from two perspectives: firstly, from a macrosociological perspective (“cleavage model”) and secondly, from a social psychology viewpoint (“Michigan model”). The first main finding was the dissolution of any socio-ecomonic imprint of SPD supporters by working class and among the low educated. While SPD ties where disproportionately common among these groups during the 1980s, that is not the case anymore at the end of my observation period in 2017. The second part of my results focus on the role of attitudes towards the SPD in the federal elections from 1994 to 2017. Varying between elections, an SPD party ID increased the likelihood of voting SPD by 60 to 80 percentage points. This along with the decreased propensity of SPD ties partly explains the losses the party has taken in the observation period. For some time, this was compensated by a popular incumbent and strong candidate effects. These short-term effects mostly vanished from 2009 on

Føreren fra Lendum

Lars Schreiber Pedersen: The Führer from Lendum In writer Erik Aalbæk Jensen’s well-known homeland novel from Vendsyssel Perleporten (The Pearl Gate) from 1964, the figure “Kratholmmanden” (the Kratholm man), is a local farm owner and Nazi leader, who with mixed success tries to win his local area’s residents over to the cause of National Socialism. Erik Aalbæk Jensen’s “Kratholmmand” character was based on Christian Mikkelstrup. During 1934–44, Mikkelstrup was a member of the National Socialist Workers’ Party of Denmark (DNSAP) and from 1935–44 he functioned as the party leader in Horns Herred in north east Vendsyssel. Despite his passionate engagement for the cause during his 10 years in the service of the party, Mikkelstrup was only able to convince a few local residents about the joy of National Socialism. DNSAP never gained any importance in north east Vendsyssel. The local party division in Lendum, which held its meetings in Mikkelstrup’s home, numbered 20–25 members at its height. Mikkelstrup was not solely to blame for the lack of support for the party in his local area. Both he and his fellow believers fought a battle that was impossible to win. The majority of local residents, like the rest of Denmark, at no point wanted to know about DNSAP – which the county council elections in 1935 and the national elections in 1935, 1939 and 1943 clearly showed – and even a leader with a bigger profile than Mikkelstrup, who was neither much of a writer or a speaker, would hardly be likely to attract more members to the party from the region. Together with a number of dissatisfied DNSAP members, he left the party in 1944 and joined the newly-formed Nazi party “Dansk National Samling”, in which however, he did not make much of an impact. With the Liberation of Denmark in May 1945, he was arrested by the resistance movement and was subsequently found guilty of passing on information to the German Security Service (Sicherheitsdienst), which had been based in Aalborg during the occupation. He received a sentence of 18 months imprisonment. He stayed faithful to his National Socialist beliefs after the war but after his release from the prison camp at Kragskovhede in August 1946, he devoted his work to running his farm at Lendum in Vendsyssel. Christian Mikkelstrup died in 1971

"Vi lever og aander i Valg". Med DNSAP til valg i Vendsyssel 1935

Umiddelbart kan det synes som lidt af et paradoks for et parti, hvis hedeste ønske det var at komme parlamentarismen og demokratiet til livs, men ikke desto mindre: Danmarks Nationalsocialistiske Arbejderparti (DNSAP) deltog i samtlige valg, partiet kunne blive opstillet til. Umiddelbart kan det synes som lidt af et paradoks for et parti, hvis hedeste ønske det var at komme parlamentarismen og demokratiet til livs, men ikke desto mindre: Danmarks Nationalsocialistiske Arbejderparti (DNSAP) deltog i samtlige valg, partiet kunne blive opstillet til.&nbsp

Taxing away M&A : the effect of corporate capital gains taxes on acquisition activity

Taxing capital gains is an important obstacle to the efficient allocation of resources because it imposes a transaction cost on the vendor which locks in appreciated assets by raising the vendor’s reservation price in prospective transactions. For M&As, this effect has been intensively studied with regard to shareholder taxation, whereas empirical evidence on the effect of capital gains taxes paid by corporations is scarce. This paper analyzes how corporate level taxation of capital gains affects inter-corporate M&As. Studying several substantial tax reforms in a panel of 30 countries for the period of 2002-2013, we identify a significant lock-in effect. Results from estimating a Poisson pseudo-maximumlikelihood (PPML) model suggest that a one percentage point decrease in the corporate capital gains tax rate would raise both the number and the total deal value of acquisitions by about 1.1% per year. We use this result to estimate an efficiency loss resulting from corporate capital gains taxation of 3.06 bn USD per year in the United States

Effects of territorial and worldwide corporation tax systems on outbound M&As

Repatriation taxes reduce the competitiveness of multinational firms from tax credit countries when bidding for targets in low tax countries. This comparative disadvantage with respect to bidders from exemption countries violates ownership neutrality, which results in production inefficiencies due to second-best ownership structures. This paper empirically estimates the magnitude of these effects. The abolishment of repatriation taxes in Japan and in the U.K. in 2009 has increased the number of acquisitions abroad by Japanese and British firms by 31.9% and 3.9 %, respectively. A similar policy switch in the U.S. is simulated to increase the number of U.S. cross-border acquisition by 17.1 %. We estimate the yearly gain in efficiency to be around 525 million dollar due to the Japanese reform and 13.5 million dollar due to the U.K. reform. Simulating such a reform for the U.S. results in a yearly efficiency gain of 1134 million dollar

Calculation of tunnel-couplings in open gate-defined disordered quantum dot systems

Quantum computation based on semiconductor electron-spin qubits requires high control of tunnel-couplings, both across quantum dots and between the quantum dot and the reservoir. The tunnel-coupling to the reservoir sets the qubit detection and initialization bandwidth for energy-resolved spin-to-charge conversion and is essential to tune single-electron transistors commonly used as charge detectors. Potential disorder and the increasing complexity of the two-dimensional gate-defined quantum computing devices sets high demands on the gate design and the voltage tuning of the tunnel barriers. We present a Green's formalism approach for the calculation of tunnel-couplings between a quantum dot and a reservoir. Our method takes into account in full detail the two-dimensional electrostatic potential of the quantum dot, the tunnel barrier and reservoir. A Markov approximation is only employed far away from the tunnel barrier region where the density of states is sufficiently large. We calculate the tunnel-coupling including potential disorder effects, which become increasingly important for large-scale silicon-based spin-qubit devices. Studying the tunnel-couplings of a single-electron transistor in Si/SiGe as a showcase, we find that charged defects are the dominant source of disorder leading to variations in the tunnel-coupling of four orders of magnitude.Comment: 10 pages, 4 figure