Density correlations in ultracold Fermi systems within the exact Richardson solution (2007)
Staudenmayer, S., Belzig, W., Bruder, C.
We discuss the occupation number correlations in an ultracold system of interacting fermionic atoms. For a system with a special energy-level distribution, viz. two multiply-degenerate levels,...
The connection between noise and quantum correlations in a double quantum dot (2007)
Bodoky, F., Belzig, W., Bruder, C.
We investigate the current and noise characteristics of a double quantum dot system. The strong correlations induced by the Coulomb interaction create entangled two-electron states and lead to...
Hammer, J. C., Cuevas, J. C., Bergeret, F. S., Belzig, W.
We present a theoretical study of the density of states and supercurrent in diffusive superconductor-normal metal-superconductor (SNS) junctions. In particular, we study the influence on these two...
Hammer, J.C., Cuevas, J.C., Bergeret, F.S., Belzig, W.
Physical Review B, 76(2007) S.064514/1-11
Electrical transport through a single-electron transistor strongly coupled to an oscillator (2006)
Doiron, C. B., Belzig, W., Bruder, C.
We investigate electrical transport through a single-electron transistor coupled to a nanomechanical oscillator. Using a combination of a master-equation approach and a numerical Monte Carlo method,...
Overscreening Diamagnetism in Cylindrical Superconductor-Normal Metal-Heterostructures (2006)
Belzig, W., Bruder, C., Nazarov, Yu. V.
We study the linear diamagnetic response of a superconducting cylinder coated by a normal-metal layer due to the proximity effect using the clean limit quasiclassical Eilenberger equations. We...
Interaction-induced Renormalization of Andreev Reflection (2006)
Titov, M., Mueller, M., Belzig, W.
We analyze the charge transport between a one-dimensional weakly interacting electron gas and a superconductor within the scaling approach in the basis of scattering states. We derive the...
Nanospintronics with carbon nanotubes (2006)
Cottet, A., Kontos, T., Sahoo, S., Man, H.T., Choi, M-S., Belzig, W., ...
Nanospintronics with carbon nanotubes (2006)
Cottet, A., Kontos, T., Sahoo, S., Man, H.T., Choi, M-S., Belzig, W., ...
Controlling spin in an electronic interferometer with spin-active interfaces (2005)
Cottet, A., Kontos, T., Belzig, W., Schonenberger, C., Bruder, C.
We consider electronic current transport through a ballistic one-dimensional quantum wire connected to two ferromagnetic leads. We study the effects of the spin-dependence of interfacial phase shifts...
Shot noise of spin current in ferromagnet-normal-metal systems (2005)
We propose a three-terminal spin-valve setup, to determine experimentally the spin-dependent shot noise, which carries information on the spin-relaxation processes. Based on a spin-dependent...
Full counting statistics of super-Poissonian shot noise in multi-level quantum dots (2005)
We examine the full counting statistics of quantum dots, which display super-Poissonian shot noise. By an extension to a generic situation with many excited states we identify the underlying...
Density correlations in ultracold atomic Fermi gases (2004)
Belzig, W., Schroll, C., Bruder, C.
We investigate density fluctuations in a coherent ensemble of interacting fermionic atoms. Adapting the concept of full counting statistics, well-known from quantum optics and mesoscopic electron...
Hansen, A. E., Kontos, T., Hoffmann, C., Oberholzer, S., Belzig, W., ...
We have measured the conductance and shot-noise of superconductor-normal metal (S-N) junctions between a Niobium (Nb) film and a 2-dimensional electron gas (2DEG), formed in an InAs-based...
Comment on "Josephson Current through a Nanoscale Magnetic Quantum Dot" (2004)
Choi, Mahn-Soo, Lee, Minchul, Kang, Kecheon, Belzig, W.
In a recent work [Phys. Rev. Lett. 93, 047002 (2004)], Siano and Egger (SE) studied Josephson current through a quantum dot in the Kondo regime using the quantum Monte Carlo (QMC) method. Several of...
Semiclassical theory of spin-polarized shot noise in mesoscopic diffusive conductors (2004)
We study fluctuations of spin-polarized currents in a three-terminal spin-valve system consisting of a diffusive normal metal wire connected by tunnel junctions to three ferromagnetic terminals....
Kondo resonance in a nanotube quantum dot coupled to a normal and a superconducting lead (2004)
Graeber, M. R., Nussbaumer, T., Belzig, W., Kontos, T., Schoenenberger, C.
We report on electrical transport measurements through a carbon nanotube quantum dot coupled to a normal and a superconducting lead. The ratio of Kondo temperature and superconducting gap...
DC-transport in superconducting point contacts: a full counting statistics view (2004)
We present a comprehensive theoretical analysis of the dc transport properties of superconducting point contacts. We determine the full counting statistics for these junctions, which allows us to...
Positive cross-correlations due to Dynamical Channel-Blockade in a three-terminal quantum dot (2004)
Cottet, A., Belzig, W., Bruder, C.
We investigate current fluctuations in a three-terminal quantum dot in the sequential tunneling regime. In the voltage-bias configuration chosen here, the circuit is operated like a beam splitter,...
Quantum Dot coupled to a normal and a superconducting lead (2004)
Graeber, M. R., Nussbaumer, T., Belzig, W., Schoenenberger, C.
We report on electrical transport measurements in a carbon nanotube quantum dot coupled to a normal and a superconducting lead. Depending on the ratio of Kondo temperature $T_{K}$ and superconducting...
Charge transport through a SET with a mechanically oscillating island (2004)
Chtchelkatchev, N. M., Belzig, W., Bruder, C.
We consider a single-electron transistor (SET) whose central island is a nanomechanical oscillator. The gate capacitance of the SET depends on the mechanical displacement, thus, the vibrations of the...
Dynamical Spin-Blockade in a quantum dot with paramagnetic leads (2004)
We investigate current fluctuations in a three-terminal quantum dot in the sequential tunneling regime. Dynamical spin blockade can be induced when the spin-degeneracy of the dot states is lifted by...
Resistance of superconducting nanowires connected to normal metal leads (2004)
Boogaard, G. R., Verbruggen, A. H., Belzig, W., Klapwijk, T. M.
We study experimentally the low temperature resistance of superconducting nanowires connected to normal metal reservoirs. We find that a substantial fraction of the nanowires is resistive, down to...
Kondo Effect and Josephson Current through a Quantum Dot between Two Superconductors (2003)
Choi, Mahn-Soo, Lee, Minchul, Kang, Kicheon, Belzig, W.
We investigate the supercurrent through a quantum dot for the whole range of couplings using the numerical renormalization group method. We find that the Josephson current switches abruptly from a...
Full Counting Statistics in Quantum Contacts (2003)
Full counting statistics is a fundamentally new concept in quantum transport. After a review of basic statistics theory, we introduce the powerful Green's function approach to full counting...
Andreev reflection eigenvalue density in mesoscopic conductors (2003)
Samuelsson, P., Belzig, W., Nazarov, Yu. V.
The energy-dependent Andreev reflection eigenvalues determine the transport properties of normal-superconducting systems. We evaluate the eigenvalue density to get an insight into formation of...
Positive cross-correlations in a three-terminal quantum dot with ferromagnetic contacts (2003)
Cottet, A., Belzig, W., Bruder, C.
We study current fluctuations in an interacting three-terminal quantum dot with ferromagnetic leads. For appropriately polarized contacts, the transport through the dot is governed by a novel...
Full counting statistics of multiple Andreev reflections (2003)
We derive the full distribution of transmitted particles through a superconducting point contact of arbitrary transparency under voltage bias. The charge transport is dominated by multiple Andreev...
Spin-Flip Noise in a Multi-Terminal Spin-Valve (2003)
We study shot noise and cross correlations in a four terminal spin-valve geometry using a Boltzmann-Langevin approach. The Fano factor (shot noise to current ratio) depends on the magnetic...
Decoherence of cold atomic gases in magnetic micro-traps (2003)
Schroll, C., Belzig, W., Bruder, C.
We derive a model to describe decoherence of atomic clouds in atom-chip traps taking the excited states of the trapping potential into account. We use this model to investigate decoherence for a...
Full counting statistics of incoherent Andreev transport (2003)
We study the full counting statistics of heterostructures consisting of normal metal parts connected to a superconducting terminal. Assuming that coherent superconducting correlations are suppressed...
Multiple Andreev Reflections in a Carbon Nanotube Quantum Dot (2003)
Buitelaar, M. R., Belzig, W., Nussbaumer, T., Babic, B., Bruder, C., Schoenenberger, C.
We report resonant multiple Andreev relections in a multiwall carbon nanotube quantum dot coupled to superconducting leads. The position and magnitude of the subharmonic gap structure is found to...
Multiple Andreev reflections in a carbon nanotube quantum dot (2003)
Buitelaar, MR, Belzig, W, Nussbaumer, T, Babic, B, Bruder, C, Schonenberger, C
We report resonant multiple Andreev reflections in a multiwall carbon nanotube quantum dot coupled to superconducting leads. The position and magnitude of the subharmonic gap structure is found to...
Multiple Andreev reflections in a carbon nanotube quantum dot (2003)
Buitelaar, MR, Belzig, W, Nussbaumer, T, Babic, B, Bruder, C, Schonenberger, C
We report resonant multiple Andreev reflections in a multiwall carbon nanotube quantum dot coupled to superconducting leads. The position and magnitude of the subharmonic gap structure is found to...
Shot Noise of Mesoscopic NS Structures: The Role of Andreev Reflection (2002)
Reulet, B., Prober, D. E., Belzig, W.
Electronic properties of mesoscopic systems made of normal metal in contact with normal and superconducting reservoirs are determined by Andreev Reflection. We address both experimentally and...
Full Counting Statistics of Superconductor--Normal-Metal Heterostructures (2002)
The article develops a powerful theoretical tool to obtain the full counting statistics. By a slight extension of the standard Keldysh method we can access immediately all correlation functions of...
Shot Noise and Proximity Effect in Superconductor--Normal-Metal Heterostructures (2002)
Belzig, W., Boerlin, J., Bruder, C., Nazarov, Yu. V.
Current noise provides useful information on correlations important for transport properties of mesoscopic systems. Of particular interest, both experimentally and theoretically, are heterostructures...
Phase Sensitive Shot Noise in an Andreev Interferometer (2002)
Reulet, B., Kozhevnikov, A. A., Prober, D. E., Belzig, W., Nazarov, Yu. V.
We investigate nonequilibrium noise in a diffusive Andreev interferometer, in which currents emerging from two Normal metal/Superconductor (N-S) interfaces can interfere. We observe a modulation of...
Josephson effect in S$_{\rm F}$XS$_{\rm F}$ junctions (2002)
Chtchelkatchev, N. M., Belzig, W., Bruder, C.
We investigate the Josephson effect in S$_{\rm F}$XS$_{\rm F}$ junctions, where S$_{\rm F}$ is a superconducting material with a ferromagnetic exchange field, and X a weak link. The critical current...
Generalized boundary conditions for the circuit theory of mesoscopic transport (2002)
Huertas-Hernando, Daniel, Nazarov, Yu. V., Belzig, W.
The circuit theory of mesoscopic transport provides a unified framework to describe spin-dependent or superconductivity-related phenomena. We extend this theory to hybrid systems of normal metals,...
Negative Magnetoresistance in Andreev Interferometers (2002)
Belzig, W., Shaikaidarov, R., Petrashov, V. V., Nazarov, Yu. V.
We consider transport in a diffusive cross-shaped Andreev interferometer geometry, both theoretically and experimentally. A strong and unexpected modulation of the conductance with the...
Full Counting Statistics of a Superconducting Beam Splitter (2002)
Boerlin, J., Belzig, W., Bruder, C.
We study the statistics of charge transport in a mesoscopic three-terminal device with one superconducting terminal and two normal-metal terminals. We calculate the full distribution of transmitted...
Negative magnetoresistance in Andreev interferometers (2002)
Belzig, W., Shaikhaidarov, R., Petrashov, V.V., Nazarov, Yu.V.
$\pi-0$ Transition in Superconductor-Ferromagnetic-Superconductor Junctions (2001)
Chtchelkatchev, N. M., Belzig, W., Nazarov, Yu. V., Bruder, C.
Superconductor-Ferromagnetic-Superconductor (SFS) Josephson junctions are known to exhibit a transition between $\pi$ and 0 states. In this note we find the $\pi-0$ phase diagram of an SFS junction...
Absolute spin-valve effect with superconducting proximity structures (2001)
Huertas-Hernando, Daniel, Nazarov, Yu. V., Belzig, W.
We investigate spin dependent transport in hybrid superconductor(S)--normal-metal(N)--ferromagnet(F) structures under conditions of proximity effect. We demonstrate the feasibility of the absolute...
Superconducting proximity effect in clean ferromagnetic layers (2001)
Zareyan, M., Belzig, W., Nazarov, Yu. V.
We investigate superconducting proximity effect in clean ferromagnetic layers with rough boundaries. The subgap density of states is formed by Andreev bound states at energies which depend on...
Full Current Statistics in Diffusive Normal-Superconductor Structures (2001)
We study the current statistics in normal diffusive conductors in contact with a superconductor. Using an extension of the Keldysh Green's function method we are able to find the full distribution of...
Proximity effect and multiple Andreev reflections in gold atomic contacts (2001)
Scheer, E., Belzig, W., Naveh, Y., Devoret, M.H., Esteve, D., Urbina, C.
Proximity Effect and Multiple Andreev Reflections in Gold Atomic Contacts (2001)
Belzig, W., Devoret, M. H., Esteve, D., Naveh, Y., Scheer, E., Urbina, C.
Full counting statistics of electron transfer between superconductors (2000)
We present an extension of the Keldysh-Green's function method, which allows to calculate the full distribution of transmitted particles through a mesoscopic superconductor. The method is applied to...
Oscillations of Andreev states in clean ferromagnetic films (2000)
Zareyan, M., Belzig, W., Nazarov, Yu. V.
We investigate the influence of the exchange field on the Andreev bound states in a ferromagnetic (F) film backed on one side by a superconductor (S). Our model accounts for diffusive reflection at...
The excitation spectrum of mesoscopic proximity structures (2000)
Pilgram, S., Belzig, W., Bruder, C.
We investigate one aspect of the proximity effect, viz., the local density of states of a superconductor-normal metal sandwich. In contrast to earlier work, we allow for the presence of an arbitrary...
Spin-accumulation and Andreev-reflection in a mesoscopic ferromagnetic wire (2000)
Belzig, W., Brataas, Arne, Nazarov, Yu. V., Bauer, Gerrit E. W.
The electron transport though ferromagnetic metal-superconducting hybrid devices is considered in the non-equilibrium Green's function formalism in the quasiclassical approximation. Attention if...
Spectral Features of the Proximity Effect (1999)
Pilgram, S., Belzig, W., Bruder, C.
We calculate the local density of states (LDOS) of a superconductor-normal metal sandwich at arbitrary impurity concentration. The presence of the superconductor induces a gap in the normal metal...
Andreev scattering in nanoscopic junctions at high magnetic fields (1999)
Suderow, H., Bascones, E., Belzig, W., Guinea, F., Vieira, S.
We report on the measurement of multiple Andreev resonances at atomic size point contacts between two superconducting nanostructures of Pb under magnetic fields higher than the bulk critical field,...
Paramagnetic instability at normal-metal - superconductor interfaces (1999)
Fauchere, A. L., Belzig, W., Blatter, G.
We study the proximity coherence in a mesoscopic normal-metal film (N) in contact with a superconductor (S). Accounting for a repulsive interaction between the electrons in the normal metal, we find...
Quasiclassical Green's function approach to mesoscopic superconductivity. (1999)
Belzig, W., Wilhelm, F.K., Bruder, C., Schön, G., Zaikin, A.D.
Superlattices and Microstructures, 25(1999) S.1251-88
Diamagnetic Response of an N-S-Proximity System at Arbitrary Impurity Concentration (1998)
Belzig, W., Bruder, C., Fauchere, A. L.
We investigate the magnetic response of normal-metal--superconductor proximity systems for arbitrary concentrations of impurities and at arbitrary temperatures. Using the quasiclassical theory a...
Quasiclassical theory of twin boundaries in High-T_c superconductors (1998)
Belzig, W., Bruder, C., Sigrist, M.
We investigate the electronic structure of twin boundaries in orthorhombically distorted high-T$_c$ materials using the quasiclassical theory of superconductivity. At low temperatures we find a local...
Local Density of States in a Dirty Normal Metal connected to a Superconductor (1996)
Belzig, W., Bruder, C., Schoen, Gerd
A superconductor in contact with a normal metal not only induces superconducting correlations, known as proximity effect, but also modifies the density of states at some distance from the interface....
Diamagnetic Response of Normal-metal -- Superconductor Double Layers (1995)
Belzig, W., Bruder, C., Schön, Gerd
The magnetic response of a proximity-coupled superconductor-normal metal sandwich is studied within the framework of the quasiclassical theory. The magnetization is evaluated for finite values of the...