We study an analytical model of a Rashba nanowire that is partially covered by and coupled to thin superconducting layer, where the uncovered region forms quantum dot. find that, even if there no topological phase possible, trivial Andreev bound state becomes pinned exponentially close zero energy as function magnetic field strength when length dot tuned with respect its spin-orbit such resonance condition Fabry-Perot type satisfied. In this case, we remains near for Zeeman energies exceed...

We study one-dimensional topological superconductor-normal (SN) and superconductor-normal-superconductor (SNS) long junctions obtained by placing a insulating nanowire in the proximity of either one or two superconductor (SC) finite-size leads. Using Majorana polarization (MP) order parameter introduced Sticlet et al. [Phys. Rev. Lett. 108, 096802 (2012)], we find that extended Andreev bound states (ABS) normal part wire acquire finite MP: For SN junction ABS spectrum exhibits zero-energy...

Considering Rashba quantum wires with a proximity-induced superconducting gap as physical realizations of Majorana bound states and dots, we calculate the overlap wave functions local on dot. We determine spin-dependent tunneling amplitudes between these two localized show that can tune into fully spin polarized regime by changing distance dot state. Upon directly applying this to model Hamiltonian, effective magnetic field flanked states. The direction induced depends occupation nonlocal...

We consider a double quantum dot coupled to two normal leads and one superconducting lead, modeling the Cooper pair beam splitter studied in recent experiments. Starting from microscopic Hamiltonian we derive general expression for branching current noise crossed correlations terms of single- two-particle Green's function electrons. then study numerically how these quantities depend on energy configuration dots presence direct tunneling between them, isolating various processes which come...

We consider a Rashba nanowire with proximity gap which can be brought into the topological phase by tuning external magnetic field or chemical potential. study spin and charge of bulk quasiparticle states when passing through transition for open closed systems. show, analytically numerically, that around reverses its sign crossing due to band inversion, independent presence Majorana fermions in system. This reversal considered as signature superconductivity accessed experimentally. find...

We study theoretically the detection of topological phase transition occurring in Rashba nanowires with proximity-induced superconductivity using a quantum dot. The bulk states lowest energy such nanowire have spin polarization parallel or antiparallel to applied magnetic field trivial phase, respectively. show that this property can be probed by dot created at end external gates. By tuning one two spin-split levels resonance states, detect band via transport measurement. This allows...

Sub-gap states in semiconducting-superconducting nanowire hybrid devices are controversially discussed as potential topologically non-trivial quantum states. One source of ambiguity is the lack an energetically and spatially well defined tunnel spectrometer. Here, we use dots directly integrated into during growth process to perform spectroscopy discrete sub-gap a long segment. In addition with standard magnetic field dependence, find trivial that independent external field, i.e. pinned...

We propose an approach allowing the computation of currents and their correlations in interacting multiterminal mesoscopic systems involving quantum dots coupled to normal and/or superconducting leads. The formalism relies on expression branching noise crossed terms one- two-particle Green's functions for electrons, which are then evaluated self-consistently within a conserving approximation. apply this Cooper-pair beam-splitter setup recently proposed [L. Hofstetter et al. Nature (London)...

We study the proximity effect in a topological nanowire tunnel coupled to an s-wave superconducting substrate. use general Green's function approach that allows us evolution of Andreev bound states wire into Majorana fermions. show strength coupling induces transition which fermionic can be destroyed when is very strong. Moreover, we provide phenomenologial effects disorder superconductor on formation note non-trivial quasiparticle broadening term take from non-topological phase certain...

We investigate numerically the possibility to detect spatial profile of Majorana fermions (MFs) by using STM tips that are made either normal or superconducting material. In both cases, we able resolve localization length and oscillation period MF wave function. show tunneling between substrate tip, necessary get information on wave-function oscillations, has be weaker in case a probe. strong regime, differential conductance saturates making it more difficult observe exponential decay MFs....

A Josephson junction may be driven through a transition where the superconducting condensate favors an odd over even number of electrons. At this switch in ground-state fermion parity, Andreev bound state crosses Fermi level, producing zero-mode that can probed by point contact to grounded metal. We calculate time-dependent charge transfer between superconductor and metal for linear sweep transition. One single quasiparticle is exchanged with $Q$ depending on coupling energies...

We study the scattering processes and associated waiting time distributions (WTDs) in heterostructures based on one-dimensional helical edge states of a two-dimensional topological insulator. In combination with proximitized $s$-wave superconductor an applied magnetic field transition occurs. Along this WTD reveals specific features related to presence Andreev bound at finite energy or Majorana zero under ideal conditions. The effects several imperfections such as disorder temperature are discussed.

We consider transport in the Poissonian regime between edge states quantum Hall effect. The backscattering potential is assumed to be arbitrary, as it allows for multiple tunneling paths. show that Schottky relation current and noise can established full generality: Fano factor corresponds electron charge (the quasiparticle charge) integer (fractional) effect, case of purely local tunneling. derive an analytical expression current, which written a albeit with renormalized amplitude depends...

Abstract The superconducting proximity effect has recently attracted a renewed interest as the basis of topologically nontrivial states in materials with large spin–orbit interaction, protected boundary useful for quantum information technologies. However, spectroscopy these is challenging because limited control conventional tunnel barriers. Here we report electronic measurements gap semiconducting indium arsenide nanowire segment coupled to superconductor, using dots formed...

We compute various current-correlation functions of electrons flowing from a topological nanowire to the tip superconducting scanning tunnel microscope and identify fingerprints Majorana bound state. In particular, spin resolved cross correlations are shown display clear distinction between presence such an exotic state (negative correlations) Andreev (positive correlations). Similarity differences with measurements normal also discussed, like robustness finite temperature, for instance.

We have measured the lifetime of spin imbalances in quasiparticle population a superconductor $({\ensuremath{\tau}}_{s})$ frequency domain. A time-dependent imbalance is created by injecting spin-polarized electrons at finite excitation frequencies into thin-film mesoscopic (Al) an in-plane magnetic field (in Pauli limit). The time-averaged value spin-imbalance signal as function ${f}_{\text{rf}}$ shows cutoff ${f}_{\text{rf}}\ensuremath{\approx}1/(2\ensuremath{\pi}{\ensuremath{\tau}}_{s})$....

We consider a biased Normal-Superconducting junction with various types of superconductivity.Depending on the class superconductivity, Majorana bound state may appear at interface.We show that this has important consequences statistical distribution time delays between detection consecutive electrons flowing out such an interface, namely waiting distribution.Therefore, quantity is shown to be clear fingerprint physics and considered as experimental signature its presence.

We study analytically and numerically the renormalization of $g$-factor in semiconducting Rashba nanowires (NWs), consisting a normal superconducting section. If potential barrier between sections is high, quantum dot (QD) formed For harmonic (hard-wall) confinement, effective all QD levels suppressed exponentially (power law) product spin-orbit interaction (SOI) wave vector length. two removed, emerging Andreev bound states less strongly. In strong SOI regime, if chemical tuned to energy...

We study the effect of a finite proximity superconducting (SC) coherence length in SN and SNS junctions consisting semiconducting topological insulating wire whose ends are connected to either one or two $s$-wave superconductors. find that such systems behave exactly as made from single for which some regions sitting on top superconductors, size SC region being determined by length. Moreover, we effects continuous phase gradients both an open closed (ring) junction. play important role...

Photo-assisted transport through a mesoscopic conductor occurs when an oscillatory (AC) voltage is superposed to the constant (DC) bias which imposed on this conductor. Of particular interest photo assisted shot noise, has been investigated theoretically and experimentally for several types of samples. For DC biased conductors, detection scheme finite frequency noise using dissipative resonant circuit, inductively coupled device, was developped recently. We argue that photo-assisted can be...

We study the Josephson effect through a magnetic molecule with anisotropic properties. Performing calculations in tunneling regime, we show that exchange coupling between electron spin on and molecular can trigger transition from $\pi$ state to 0 state, how anisotropy affects this transition. behavior of critical current as function an external field give access valuable information about molecule.

We compute the fluctuations of number bosons with a given momentum for Tonks-Girardeau gas at zero temperature. show that correlations between opposite states, which are an important identifying characteristic long-range order in weakly interacting Bose systems, suppressed and full distribution nonzero is exponential. The quasicondensate however quasi-Gaussian. experimental relevance our findings recent cold-atom experiments discussed.