Majorana Superconducting Qubit

We propose a platform for universal quantum computation that uses conventional $s$-wave superconducting leads to address a topological qubit stored in spatially separated Majorana bound states in a multi-terminal topological superconductor island. Both the manipulation and read-out of this "Majorana superconducting qubit" are realized by tunnel couplings between Majorana bound states and the superconducting leads. The ability of turning on and off tunnel couplings on-demand by local gates enables individual qubit addressability while avoiding cross-talk errors. By combining the scalability of superconducting qubit and the robustness of topological qubits, the Majorana superconducting qubit may provide a promising and realistic route towards quantum computation

Parity-controlled 2π2\pi Josephson effect mediated by Majorana Kramers pairs

We study a time-reversal-invariant topological superconductor island hosting spatially separated Majorana Kramers pairs, with weak tunnel couplings to two s-wave superconducting leads. When the topological superconductor island is in the Coulomb blockade regime, we predict that a Josephson current flows between the two leads due to a non-local transfer of Cooper pairs mediated by the Majorana Kramers pairs. Interestingly, we find that the sign of the Josephson current is controlled by the joint parity of all four Majorana bound states on the island. Consequently, this parity-controlled Josephson effect can be used for qubit read-out in Majorana-based quantum computing

Spin-valley density wave in moir\'e materials

We introduce and study a minimum two-orbital Hubbard model on a triangular lattice, which captures the key features of both the trilayer ABC-stacked graphene-boron nitride heterostructure and twisted transition metal dichalcogenides in a broad parameter range. Our model comprises first- and second-nearest neighbor hoppings with valley-contrasting flux that accounts for trigonal warping in the band structure. For the strong-coupling regime with one electron per site, we derive a spin-orbital exchange Hamiltonian and find the semiclassical ground state to be a spin-valley density wave. We show that a relatively small second-neighbor exchange interaction is sufficient to stabilize the ordered state against quantum fluctuations. Effects of spin- and valley Zeeman fields as well as thermal fluctuations are also examined

Heinrich Schütz y J. S. Bach en la liturgia protestante

Fil: Schrade, Leo

Proximity-induced Josephson π\pi-Junctions in Topological Insulators

We study two microscopic models of topological insulators in contact with an $s$-wave superconductor. In the first model the superconductor and the topological insulator are tunnel coupled via a layer of scalar and of randomly oriented spin impurities. Here, we require that spin-flip tunneling dominates over spin-conserving one. In the second model the tunnel coupling is realized by an array of single-level quantum dots with randomly oriented spins. It is shown that the tunnel region forms a $\pi$-junction where the effective order parameter changes sign. Interestingly, due to the random spin orientation the effective descriptions of both models exhibit time-reversal symmetry. We then discuss how the proposed $\pi$-junctions support topological superconductivity without magnetic fields and can be used to generate and manipulate Kramers pairs of Majorana fermions by gates

ELECTIONS Ethics in Government: Regulate Lobbyist Gifts and Contributions to Public Officers and Limit Campaign Contributions

The Act regulates the activities of lobbyists and provides maximum campaign contributions which may be received by public officers and public employees. It provides a system for the registration of lobbyists, and it requires lobbyists to prepare and submit expenditures reports to the State Ethics Commission. The Act also limits campaign contributions which candidates for public office may accept to an aggregate amount of $1000 or$2500, depending upon the type of public office the candidate is seeking. A contribution to the campaign committee of a candidate for public office is considered a contribution to the candidate. The Act provides that, for any election other than a general primary, candidates for public office who will not be on the ballot at an election may not receive any contributions whatsoever. The Act also provides examples of things of value ; which public officials may receive without violating the provisions against bribery

Governance at Stake

Afghan Higher Education has become the most sensitive field of reforms on all levels of governance: rule of law, welfare and security. Compared to primary and secondary education, access to the universities is still a neuralgic point for status distribution and the stabilization of the entire system of education. Admission policies and traditional forms of reproduc- ing disciplinary elites endanger a differentiated development of qualifications and diversified status. The Afghan system will need its own research in Higher Education, and then must develop a minimal base for disciplinary research. It is likely that Higher Education will play an important role during the transformation period 2014-2024 in fields like urbanization, emerg- ing middle class elite, and serving schools by improved teacher training. It will be central to peace-building processes by comprehensive reforms in its governance structure. How much state will be needed in order to provide fair and equal access to the common good of Higher Education, and how much private and individual initiative must emerge in order to create quality and stability of the system? – These are central questions of this working paper.Das afghanische Hochschulsystem hat unter den Gewalteinwirkungen eines dreißigjährigen Krieges stark gelitten und kann die Erfordernisse eines modernen tertiären Sektors nicht erfüllen. Diese sind ihm durch die Intervention ab 2001 und die Aussicht auf eine Transfor- mationsperiode 2014-2024 aber auferlegt. Die Governance von Hochschulsystemen greift tief in das Rechtssystem, in die Wohlfahrtspolitik und in die Gewährleistung von Sicherheit ein. Nicht nur Legitimation durch Statuszuweisung und Effektivität durch Allokation von Quali- fikationen auf dem Arbeitsmarkt sind gefragt. Die Zulassungspolitik zur Universität kann schon vor der Politisierung durch die Hochschule zu gewaltsamer Destabilisierung führen. Die Einbettung der afghanischen Hochschulen in das globale System der akademischen Re- geln wird ebenso erörtert wie Beispiele für Fehlentwicklungen und mögliche Reformen. Für weiteren friedlichen Aufbau sind bestimmte Voraussetzungen im Hochschulbereich auch de- shalb zwingend, weil sie Entscheidungen über den Grad an Staatlichkeit und nichtstaatlicher Initiative festlegen sollten