P-wave Cooper pair splitting

Splitting of Cooper pairs has recently been realized experimentally for s-wave Cooper pairs. A split Cooper pair represents an entangled two-electron pair state which has possible application in on-chip quantum computation. Likewise the spin-activity of interfaces in nanoscale tunnel junctions has been investigated theoretically and experimentally in recent years. However, the possible implications of spin-active interfaces in Cooper pair splitters so far have not been investigated. We analyse the current and the cross correlation of currents in a superconductor ferromagnet beamsplitter including spin-active scattering. Using the Hamiltonian formalism we calculate the cumulant generating function of charge transfer. As a first step, we discuss characteristics of the conductance for crossed Andreev reflection in superconductor ferromagnet beamsplitters with s-wave and p-wave superconductors and no spin-active scattering. In a second step, we consider spin-active scattering and show how to realize p-wave splitting only using a s-wave superconductor via the process of spin-flipped crossed Andreev reflection. We present results for the conductance and cross correlations. Spin-activity of interfaces in Cooper pair splitters allows for new features in ordinary s-wave Cooper pair splitters, that can otherwise only be realised by using p-wave superconductors. In particular it provides access to Bell states different from the typical spin singlet state.Comment: 7 pages, 2 figures, accepted by Beilstein Journal of Nanotechnology, references correcte

Charge transfer statistics and entanglement in normal-quantum dot-superconductor hybrid structures

We analyze the full counting statistics (FCS) of a single-site quantum dot coupled to multiple metallic electrodes in the normal state and a superconductor for arbitrary transmission. We present an analytical solution of the problem taking into account the full energy dependence of the transmission coefficient. We identify two transport processes as sources of entanglement between the current carriers by observing positive cross current correlations. Furthermore, we consider ferromagnetic electrodes and show how they can be used as detectors in experiments violating the Bell-Clauser-Horne-Shimony-Holt inequality.Comment: 6 pages, 3 figures, typos fixed, references adde

Full counting statistics of interacting quantum dots contacted by a normal metal and a superconductor

We investigate the effects of Coulomb interaction on charge transfer through a quantum dot attached to a normal and a superconducting lead. While for voltages much larger than the gap we recover the usual result for normal conductors, for voltages much smaller than the gap superconducting correlations lead to a drastically different behavior. Especially, the usual charge doubling in the normal case is reflected in the occurence of quartets due to the onsite interaction.Comment: 6 pages, 3 figures, accepted by EP

Entanglement witnessing in superconducting beamsplitters

We analyse a large class of superconducting beamsplitters for which the Bell parameter (CHSH violation) is a simple function of the spin detector efficiency. For these superconducting beamsplitters all necessary information to compute the Bell parameter can be obtained in Y-junction setups for the beamsplitter. Using the Bell parameter as an entanglement witness, we propose an experiment which allows to verify the presence of entanglement in Cooper pair splitters.Comment: 5 pages, 2 figures, accepted for publication in EP

Home country effects of offshoring. A critical survey on empirical literature.

The International fragmentation of production processes is of rising importance. One part of this fragmentation involves the relocation of a production process from a home- to a new host country. This literature survey deals with the effects of such relocations on the home country. First of all, we try to conceptualize the terms and definitions most frequently used in this context which are "outsourcing", "offshore outsourcing" and "offshoring". Despite the fact that there is little textual documentation dealing directly with the phenomena of offshoring and offshore outsourcing we try to give an overview of possible empirical literature to which one can regard to. Including FDI literature we try to cover empirical literature which can provide helpful insight on the effects of a relocation to foreign countries on the home country in connection with wages, skill upgrading, prices, profits, taxes and unions. (author's abstract)Series: Discussion Papers SFB International Tax Coordinatio