Results for "V. Meden"

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Investigating the roots of the nonlinear Luttinger liquid phenomenologyApr 12 2019The nonlinear Luttinger liquid phenomenology of one-dimensional correlated Fermi systems is an attempt to describe the effect of the band curvature beyond the Tomonaga-Luttinger liquid paradigm. It relies on the observation that the dynamical structure ... More
How universal is the one-particle Green's function of a Luttinger liquid?Oct 26 1998The one-particle Green's function of the Tomonaga-Luttinger model for one-dimensional interacting Fermions is discussed. Far away from the origin of the plane of space-time coordinates the function falls off like a power law. The exponent depends on the ... More
Correlation effects on electronic transport through dots and wiresApr 12 2006We investigate how two-particle interactions affect the electronic transport through meso- and nanoscopic systems of two different types: quantum dots with local Coulomb correlations and quasi one-dimensional quantum wires of interacting electrons. A ... More
Spectral sum rules for the Tomonaga-Luttinger modelMay 19 1993In connection with recent publications we discuss spectral sum rules for the Tomonaga-Luttinger model without using the explicit result for the one-electron Green's function. They are usefull in the interpretation of recent high resolution photoemission ... More
Renormalization group study of Luttinger liquids with boundariesSep 11 2009Dec 04 2009We use Wilsons weak coupling ``momentum'' shell renormalization group method to show that two-particle interaction terms commonly neglected in bosonization of one-dimensional correlated electron systems with open boundaries are indeed irrelevant in the ... More
Fermion-boson transmutation and comparison of statistical ensembles in one dimensionJun 05 1996The theoretical description of interacting fermions in one spatial dimension is simplified by the fact that the low energy excitations can be described in terms of bosonic degrees of freedom. This fermion-boson transmutation (FBT) which lies at the heart ... More
Correlation induced resonances in transport through coupled quantum dotsOct 26 2005Mar 22 2006We investigate the effect of local electron correlations on transport through parallel quantum dots. The linear conductance as a function of gate voltage is strongly affected by the interplay of the interaction U and quantum interference. We find a pair ... More
Nonuniversal spectral properties of the Luttinger modelFeb 19 1993The one electron spectral functions for the Luttinger model are discussed for large but finite systems. The methods presented allow a simple interpretation of the results. For finite range interactions interesting nonunivesal spectral features emerge ... More
Comment on "Canonical and Mircocanonical Calculations for Fermi Systems"Nov 29 2000In the context of nuclear physics Pratt recently investigated noninteracting Fermi systems described by the microcanonical and canonical ensemble. As will be shown his discussion of the model of equally spaced levels contains a flaw and a statement which ... More
The spectral function of the Tomonaga-Luttinger model revisited: power laws and universalitySep 23 2015Feb 05 2016We reinvestigate the momentum-resolved single-particle spectral function of the Tomonaga-Luttinger model. In particular, we focus on the role of the momentum-dependence of the two-particle interaction V(q). Usually, V(q) is assumed to be a constant and ... More
Spin-charge separation in transport through Luttinger liquid ringsMar 14 2008Apr 24 2008We investigate how the different velocities characterizing the low-energy spectral properties and the low-temperature thermodynamics of one-dimensional correlated electron systems (Luttinger liquids) affect the transport properties of ring-like conductors. ... More
Supercurrent and multiple singlet-doublet phase transitions of a quantum dot Josephson junction inside an Aharonov-Bohm ringOct 21 2008Jan 28 2009We study a quantum dot Josephson junction inside an Aharonov-Bohm environment. The geometry is modeled by an Anderson impurity coupled to two directly-linked BCS leads. We illustrate that the well-established picture of the low-energy physics being governed ... More
The conductance of interacting nano-wiresOct 23 2002Mar 21 2003The conductance of one-dimensional nano-wires of interacting electrons connected to non-interacting leads is calculated in the linear response regime. Two different approaches are used: a many-body Green function technique and a relation to the persistent ... More
Persistent currents in mesoscopic rings: A numerical and renormalization group studySep 25 2002The persistent current in a lattice model of a one-dimensional interacting electron system is systematically studied using a complex version of the density matrix renormalization group algorithm and the functional renormalization group method. We mainly ... More
Spin-polarized currents through interacting quantum wires with nonmagnetic leadsNov 13 2008We study the performance of a quantum wire spin filter that is based on the Rashba spin-orbit interaction in the presence of the electron-electron interaction. The finite length wire is attached to two semi-infinite nonmagnetic leads. Analyzing the spin ... More
Luttinger liquid properties of the steady state after a quantum quenchApr 22 2013Oct 19 2013We study the dynamics resulting out of an abrupt change of the two-particle interaction in two models of closed one-dimensional Fermi systems: (a) the field theoretical Tomonaga-Luttinger model and (b) a microscopic lattice model. Using a nonperturbative ... More
Spin-orbit coupling effects in one-dimensional ballistic quantum wiresSep 07 2007Oct 23 2007We study the spin-dependent electronic transport through a one-dimensional ballistic quantum wire in the presence of Rashba spin-orbit interaction. In particular, we consider the effect of the spin-orbit interaction resulting from the lateral confinement ... More
The interacting resonant level model in nonequilibrium: finite temperature effectsOct 04 2012Mar 13 2013We study the steady-state properties as well as the relaxation dynamics of the nonequilibrium interacting resonant level model at finite temperatures. It constitutes the prototype model of a correlated charge fluctuating quantum dot. The two reservoirs ... More
Relaxation dynamics of an exactly solvable electron-phonon modelJun 01 2010Aug 24 2010We address the question whether observables of an exactly solvable model of electrons coupled to (optical) phonons relax into large time stationary state values and investigate if the asymptotic expectation values can be computed using a stationary density ... More
Josephson current through a single Anderson impurity coupled to BCS leadsNov 05 2007Jan 02 2008We investigate the Josephson current J(\phi) through a quantum dot embedded between two superconductors showing a phase difference \phi. The system is modeled as a single Anderson impurity coupled to BCS leads, and the functional and the numerical renormalization ... More
Interplay of Coulomb interaction and spin-orbit effects in multi-level quantum dotsApr 10 2012Jul 06 2012We study electron transport through a multi-level quantum dot with Rashba spin-orbit interaction in the presence of local Coulomb repulsion. Motivated by recent experiments, we compute the level splitting induced by the spin-orbit interaction at finite ... More
Dynamical regimes of dissipative quantum systemsSep 30 2013May 15 2014We reveal several distinct regimes of the relaxation dynamics of a small quantum system coupled to an environment within the plane of the dissipation strength and the reservoir temperature. This is achieved by discriminating between coherent dynamics ... More
Kondo physics in transport through a quantum dot with Luttinger liquid leadsSep 22 2005We study the gate voltage dependence of the linear conductance through a quantum dot coupled to one-dimensional leads. For interacting dot electrons but noninteracting leads Kondo physics implies broad plateau-like resonances. In the opposite case Luttinger ... More
Finite-temperature linear conductance from the Matsubara Green function without analytic continuation to the real axisJul 20 2010Aug 24 2010We illustrate how to calculate the finite-temperature linear-response conductance of quantum impurity models from the Matsubara Green function. A continued fraction expansion of the Fermi distribution is employed which was recently introduced by Ozaki ... More
Quench dynamics of the Tomonaga-Luttinger model with momentum dependent interactionMar 05 2012We study the relaxation dynamics of the one-dimensional Tomonaga-Luttinger model after an interaction quench paying particular attention to the momentum dependence of the two-particle interaction. Several potentials of different analytical form are investigated ... More
Efficiency and power of a thermoelectric quantum dot deviceJan 15 2013Jun 19 2013We study linear response and nonequilibrium steady-state thermoelectric transport through a single-level quantum dot tunnel coupled to two reservoirs held at different temperatures as well as chemical potentials. A fermion occupying the dot interacts ... More
Spectral properties of one-dimensional Fermi systems after an interaction quenchMay 15 2014Sep 21 2014We show that the single-particle spectral properties of gapless one-dimensional Fermi systems in the Luttinger liquid state reached at intermediate times after an abrupt quench of the two-particle interaction are highly indicative of the unusual nonequilibrium ... More
Supercurrent through a serial quantum dot close to singlet-triplet degeneracyJul 28 2011Oct 29 2011We investigate two serially-aligned quantum dots in the molecular regime of large tunnel couplings t. A Zeeman field B is used to tune the energy difference of singlet and triplet spin configurations. Attaching this geometry to BCS source and drain leads ... More
Liouvillian Approach to the Integer Quantum Hall Effect TransitionFeb 14 2000We present a novel approach to the localization-delocalization transition in the integer quantum Hall effect. The Hamiltonian projected onto the lowest Landau level can be written in terms of the projected density operators alone. This and the closed ... More
Influence of the contacts on the conductance of interacting quantum wiresApr 19 2006Jul 05 2006We investigate how the conductance G through a clean interacting quantum wire is affected by the presence of contacts and noninteracting leads. The contacts are defined by a vanishing two-particle interaction to the left and a finite repulsive interaction ... More
Charging of a quantum dot coupled to Luttinger liquid leadsMay 07 2007Aug 20 2007Luttinger liquid behavior of one-dimensional correlated electron systems is characterized by power-law scaling of a variety of physical observables with exponents determined by a single interaction dependent parameter K. We suggest a setup to study Luttinger ... More
Indirect forces between impurities in one-dimensional quantum liquidsMar 05 2007We investigate the indirect interaction between two isolated impurities in a Luttinger liquid described by a microscopic lattice model. To treat the electron-electron interaction U the functional renormalization group method is used. For comparison we ... More
Coupling-geometry-induced temperature scales in the conductance of Luttinger liquid wiresApr 25 2008Apr 14 2009We study electronic transport through a one-dimensional, finite-length quantum wire of correlated electrons (Luttinger liquid) coupled at arbitrary position via tunnel barriers to two semi-infinite, one-dimensional as well as stripe-like (two-dimensional) ... More
Orthogonality catastrophe in a one-dimensional system of correlated electronsJul 08 1997We present a detailed numerical study of the orthogonality catastrophe exponent for a one-dimensional lattice model of spinless fermions with nearest neighbor interaction using the density matrix remormalization group algorithm. Keeping up to 1200 states ... More
A novel approach to transport through correlated quantum dotsMar 20 2006May 15 2006We investigate the effect of local Coulomb correlations on electronic transport through a variety of coupled quantum dot systems connected to Fermi liquid leads. We use a newly developed functional renormalization group scheme to compute the gate voltage ... More
Local spectral properties of Luttinger liquids: scaling versus nonuniversal energy scalesNov 30 2011Feb 10 2012Motivated by recent scanning tunneling and photoemission spectroscopy measurements on self-organized gold chains on a germanium surface we reinvestigate the local single-particle spectral properties of Luttinger liquids. In the first part we use the bosonization ... More
Universal quench dynamics of interacting quantum impurity systemsJun 20 2014Sep 21 2014The equilibrium physics of quantum impurities frequently involves a universal crossover from weak to strong reservoir-impurity coupling, characterized by single-parameter scaling and an energy scale $T_K$ (Kondo temperature) that breaks scale invariance. ... More
Functional renormalization group for non-equilibrium quantum many-body problemsSep 19 2006Nov 23 2006We extend the concept of the functional renormalization for quantum many-body problems to non-equilibrium situations. Using a suitable generating functional based on the Keldysh approach, we derive a system of coupled differential equations for the $m$-particle ... More
Scaling behavior of impurities in mesoscopic Luttinger liquidsApr 18 2001Using a functional renormalization group we compute the flow of the renormalized impurity potential for a single impurity in a Luttinger liquid over the entire energy range - from the microscopic scale of a lattice-fermion model down to the low-energy ... More
Fermionic renormalization group methods for transport through inhomogeneous Luttinger liquidsJan 25 2008Apr 30 2008We compare two fermionic renormalization group methods which have been used to investigate the electronic transport properties of one-dimensional metals with two-particle interaction (Luttinger liquids) and local inhomogeneities. The first one is a poor ... More
Scaling of the conductance in a quantum wireMar 21 2003Jul 18 2003The conductance G of an interacting nano-wire containing an impurity and coupled to non-interacting semi-infinite leads is studied using a functional renormalization group method. We obtain results for microscopic lattice models without any further idealizations. ... More
Quantum critical behavior of the one-dimensional ionic Hubbard modelJul 30 2003We study the zero-temperature phase diagram of the half-filled one-dimensional ionic Hubbard model. This model is governed by the interplay of the on-site Coulomb repulsion and an alternating one-particle potential. Various many-body energy gaps, the ... More
Junctions of one-dimensional quantum wires - correlation effects in transportJan 31 2005Apr 04 2005We investigate transport of spinless fermions through a single site dot junction of M one-dimensional quantum wires. The semi-infinite wires are described by a tight-binding model. Each wire consists of two parts: the non-interacting leads and a region ... More
A renormalization group approach to time dependent transport through correlated quantum dotsNov 29 2011We introduce a real time version of the functional renormalization group which allows to study correlation effects on nonequilibrium transport through quantum dots. Our method is equally capable to address (i) the relaxation out of a nonequilibrium initial ... More
Renormalization group flows in one-dimensional lattice models: impurity scaling, umklapp scattering and the orthogonality catastropheSep 05 2014We show that to understand the orthogonality catastrophe in the half-filled lattice model of spinless fermions with repulsive nearest neighbor interaction and a local impurity in its Luttinger liquid phase one has to take into account (i) the impurity ... More
Renormalization in periodically driven quantum dotsAug 06 2015Jan 15 2016We report on strong renormalization encountered in periodically driven interacting quantum dots in the non-adiabatic regime. Correlations between lead and dot electrons enhance or suppress the amplitude of driving depending on the sign of the interaction. ... More
Improved transport equations including correlations for electron-phonon systems. Comparison with exact solutions in one dimensionOct 16 1996We study transport equations for quantum many-particle systems in terms of correlations by applying the general formalism developed in an earlier paper to exactly soluble electron-phonon models. The one-dimensional models considered are the polaron model ... More
Current noise of the interacting resonant level modelNov 01 2015Feb 05 2016We study the zero-frequency current noise of the interacting resonant level model for arbitrary bias voltages using a functional renormalization group approach. For this we extend the existing nonequilibrium scheme by deriving and solving flow equations ... More
Luttinger liquid universality in the time evolution after an interaction quenchMay 09 2012We provide strong evidence that the relaxation dynamics of one-dimensional, metallic Fermi systems resulting out of an abrupt amplitude change of the two-particle interaction has aspects which are universal in the Luttinger liquid sense: The leading long-time ... More
Spin-orbit interaction and asymmetry effects on Kondo ridges at finite magnetic fieldNov 26 2010Mar 12 2011We study electron transport through a serial double quantum dot with Rashba spin-orbit interaction (SOI) and Zeeman field of amplitude B in presence of local Coulomb repulsion. The linear conductance as a function of a gate voltage Vg equally shifting ... More
Functional renormalization group study of the interacting resonant level model in and out of equilibriumNov 26 2009Mar 01 2010We investigate equilibrium and steady-state non-equilibrium transport properties of a spinless resonant level locally coupled to two conduction bands of width ~\Gamma via a Coulomb interaction U and a hybridization t'. In order to study the effects of ... More
A junction of three quantum wires: restoring time-reversal symmetry by interactionNov 24 2004Mar 09 2005We investigate transport of correlated fermions through a junction of three one-dimensional quantum wires pierced by a magnetic flux. We determine the flow of the conductance as a function of a low-energy cutoff in the entire parameter space. For attractive ... More
Functional renormalization group approach to zero-dimensional interacting systemsApr 29 2004We apply the functional renormalization group method to the calculation of dynamical properties of zero-dimensional interacting quantum systems. As case studies we discuss the anharmonic oscillator and the single impurity Anderson model. We truncate the ... More
Boundary effects on one-particle spectra of Luttinger liquidsMar 07 1999Dec 22 1999We calculate one-particle spectra for a variety of models of Luttinger liquids with open boundary conditions. For the repulsive Hubbard model the spectral weight close to the boundary is enhanced in a large energy range around the chemical potential. ... More
Correlation effects on resonant tunneling in one-dimensional quantum wiresMar 26 2004Nov 11 2004We study resonant tunneling in a Luttinger liquid with a double barrier enclosing a dot region. Within a microscopic model calculation the conductance G as a function of temperature T is determined over several decades. We identify parameter regimes in ... More
A single impurity in a Luttinger liquid: How it "cuts" the chainSep 02 2001Nov 20 2001Using a fermionic renormalization group method we present a simple real space picture of the strong influence an impurity has on the electronic properties of a Luttinger liquid. We compute the flow of the renormalized impurity potential for a single impurity ... More
A quantum criticality perspective on the charging of narrow quantum-dot levelsOct 14 2008Mar 26 2009Understanding the charging of exceptionally narrow levels in quantum dots in the presence of interactions remains a challenge within mesoscopic physics. We address this fundamental question in the generic model of a narrow level capacitively coupled to ... More
Phase lapses in transmission through interacting two-level quantum dotsDec 19 2006We investigate the appearance of pi lapses in the transmission phase theta of a two-level quantum dot with Coulomb interaction U. Using the numerical and functional renormalization group methods we study the entire parameter space for spin-polarized as ... More
Manipulating the magnetic state of a carbon nanotube Josephson junction using the superconducting phaseJan 14 2015Jun 10 2015The magnetic state of a quantum dot attached to superconducting leads is experimentally shown to be controlled by the superconducting phase difference across the dot. This is done by probing the relation between the Josephson current and the superconducting ... More
Impurity and correlation effects on transport in one-dimensional quantum wiresNov 11 2004Jan 17 2005We study transport through a one-dimensional quantum wire of correlated fermions connected to semi-infinite leads. The wire contains either a single impurity or two barriers, the latter allowing for resonant tunneling. In the leads the fermions are assumed ... More
Small quenches and (pre-)thermalizationOct 11 2016We study the expectation values of observables and correlation functions at long times after a global quantum quench. Our focus is on fermionic many-body models and small quenches. The system is prepared in an eigenstate of an initial Hamiltonian, and ... More
The Ohmic two-state system from the perspective of the interacting resonant level model: Thermodynamics and transient dynamicsJan 15 2016Apr 20 2016We investigate the thermodynamics and transient dynamics of the (unbiased) Ohmic two-state system by exploiting the equivalence of this model to the interacting resonant level model. For the thermodynamics, we show, by using the numerical renormalization ... More
Mesoscopic to universal crossover of transmission phase of multi-level quantum dotsSep 08 2006Mar 22 2007Transmission phase \alpha measurements of many-electron quantum dots (small mean level spacing \delta) revealed universal phase lapses by \pi between consecutive resonances. In contrast, for dots with only a few electrons (large \delta), the appearance ... More
Probing electron-electron interaction in quantum Hall systems with scanning tunneling spectroscopyDec 09 2010Apr 15 2011Using low-temperature scanning tunneling spectroscopy applied to the Cs-induced two-dimensional electron system (2DES) on p-type InSb(110), we probe electron-electron interaction effects in the quantum Hall regime. The 2DES is decoupled from p-doped bulk ... More
A finite-frequency functional RG approach to the single impurity Anderson modelJun 02 2008Jul 29 2008We use the Matsubara functional renormalization group (FRG) to describe electronic correlations within the single impurity Anderson model. In contrast to standard FRG calculations, we account for the frequency-dependence of the two-particle vertex in ... More
Functional renormalization group study of the Anderson--Holstein modelSep 24 2013We present a comprehensive study of the spectral and transport properties in the Anderson--Holstein model both in and out of equilibrium using the functional renormalization group (FRG). We show how the previously established machinery of Matsubara and ... More
Tuning the Josephson current in carbon nanotubes with the Kondo effectOct 09 2008May 04 2009We investigate the Josephson current in a single wall carbon nanotube connected to superconducting electrodes. We focus on the parameter regime in which transport is dominated by Kondo physics. A sizeable supercurrent is observed for odd number of electrons ... More
Renormalization-group analysis of the one-dimensional extended Hubbard model with a single impuritySep 01 2005Feb 01 2006We analyze the one-dimensional extended Hubbard model with a single static impurity by using a computational technique based on the functional renormalization group. This extends previous work for spinless fermions to spin-1/2 fermions. The underlying ... More
Luttinger liquids with boundaries: Power-laws and energy scalesFeb 15 2000We present a study of the one-particle spectral properties for a variety of models of Luttinger liquids with open boundaries. We first consider the Tomonaga-Luttinger model using bosonization. For weak interactions the boundary exponent of the power-law ... More
Oscillatory dynamics and non-markovian memory in dissipative quantum systemsNov 01 2012Mar 13 2013The nonequilibrium dynamics of a small quantum system coupled to a dissipative environment is studied. We show that (1) the oscillatory dynamics close to a coherent-to-incoherent transition is surprisingly different from the one of the classical damped ... More
Charge transport through single molecules, quantum dots, and quantum wiresMay 07 2010We review recent progresses in the theoretical description of correlation and quantum fluctuation phenomena in charge transport through single molecules, quantum dots, and quantum wires. A variety of physical phenomena is addressed, relating to co-tunneling, ... More
Non-equilibrium current and relaxation dynamics of a charge-fluctuating quantum dotNov 29 2009Jul 07 2010We study the steady-state current in a minimal model for a quantum dot dominated by charge fluctuations and analytically describe the time evolution into this state. The current is driven by a finite bias voltage V across the dot, and two different renormalization ... More
Functional renormalization group for Luttinger liquids with impuritiesMar 19 2004Aug 31 2004We improve the recently developed functional renormalization group (fRG) for impurities and boundaries in Luttinger liquids by including renormalization of the two-particle interaction, in addition to renormalization of the impurity potential. Explicit ... More
Magnetic-Field Dependence of Tunnel Couplings in Carbon Nanotube Quantum DotsApr 30 2012May 01 2012By means of sequential and cotunneling spectroscopy, we study the tunnel couplings between metallic leads and individual levels in a carbon nanotube quantum dot. The levels are ordered in shells consisting of two doublets with strong- and weak-tunnel ... More
Quench dynamics of correlated quantum dotsApr 10 2012We study the relaxation dynamics of a quantum dot with local Coulomb correlations coupled to two noninteracting leads which are held in grandcanonical equilibrium. Only charge degrees of freedom are considered and the dot is described by a model which ... More
Nonequilibrium functional renormalization group for interacting quantum systemsFeb 21 2007Oct 12 2007We propose a nonequilibrium version of functional renormalization within the Keldysh formalism by introducing a complex valued flow parameter in the Fermi or Bose functions of each reservoir. Our cutoff scheme provides a unified approach to equilibrium ... More
Anomalous scaling and spin-charge separation in coupled chainsFeb 23 1995We use a bosonization approach to show that the three dimensional Coulomb interaction in coupled metallic chains leads to a Luttinger liquid for vanishing inter-chain hopping $t_{\bot}$, and to a Fermi liquid for any finite $t_{\bot}$. However, for small ... More
Crossover between Luttinger and Fermi liquid behavior in weakly coupled metallic chainsJan 06 1997We use higher-dimensional bosonization to study the normal state of electrons in weakly coupled metallic chains interacting with long-range Coulomb forces. Particular attention is paid to the crossover between Luttinger and Fermi liquid behavior as the ... More
Functional renormalization group in Floquet spaceSep 09 2016Dec 20 2016We present an extension of the functional renormalization group to Floquet space, which enables us to treat the long time behavior of interacting time periodically driven quantum dots. It is one of its strength that the method is neither bound to small ... More
Functional renormalization group in Floquet spaceSep 09 2016Nov 17 2016We present an extension of the functional renormalization group to Floquet space, which enables us to treat the long time behavior of interacting time periodically driven quantum dots. It is one of its strength that the method is neither bound to small ... More
Functional renormalization group in Floquet spaceSep 09 2016We present an extension of the functional renormalization group to Floquet space, which enables us to treat the long time behavior of interacting time periodically driven quantum dots. It is one of its strength that the method is neither bound to small ... More
A gentle introduction to the functional renormalization group: the Kondo effect in quantum dotsDec 09 2006Jul 12 2007The functional renormalization group provides an efficient description of the interplay and competition of correlations on different energy scales in interacting Fermi systems. An exact hierarchy of flow equations yields the gradual evolution from a microscopic ... More
Functional renormalization group approach to correlated fermion systemsMay 26 2011Jun 02 2012Numerous correlated electron systems exhibit a strongly scale-dependent behavior. Upon lowering the energy scale, collective phenomena, bound states, and new effective degrees of freedom emerge. Typical examples include (i) competing magnetic, charge, ... More
Magneto-electric spectroscopy of Andreev bound states in Josephson quantum dotsMay 30 2016Oct 11 2016We theoretically investigate the behavior of Andreev levels in a single-orbital interacting quantum dot in contact to superconducting leads, focusing on the effect of electrostatic gating and applied magnetic field, as relevant for recent experimental ... More
Detecting phases in one-dimensional many-fermion systems with the functional renormalization groupMar 01 2018Jun 15 2018The functional renormalization group (FRG) has been used widely to investigate phase diagrams, in particular the one of the two-dimensional Hubbard model. So far, the study of one-dimensional models has not attracted as much attention. We use the FRG ... More
RG transport theory for open quantum systems: Charge fluctuations in multilevel quantum dots in and out of equilibriumOct 29 2018We present the real-time renormalization group (RTRG) method as a method to describe the stationary state current through generic multi-level quantum dots with a complex setup in nonequilibrium. The employed approach consists of a very rudiment approximation ... More
Renormalization group flow of the Luttinger-Ward functional: conserving approximations and application to the Anderson impurity modelFeb 19 2016May 27 2016We study the renormalization group flow of the Luttinger-Ward functional and of its two-particle irreducible vertex functions, given a cut-off in the two-particle interaction. We derive a conserving approximation to the flow and relate it to the fluctuation ... More
Non-equilibrium transport through a Josephson quantum dotFeb 26 2014Jun 11 2014We study the electronic current through a quantum dot coupled to two superconducting leads which is driven by either a voltage $V$ or temperature $\Delta T$ bias. Finite biases beyond the linear response regime are considered. The local two-particle interaction ... More
Temperature induced phase averaging in one-dimensional mesoscopic systemsJun 19 2006Feb 21 2007We analyse phase averaging in one-dimensional interacting mesoscopic systems with several barriers and show that for incommensurate positions an independent average over several phases can be induced by finite temperature. For three strong barriers with ... More
Two-particle irreducible functional renormalization group schemes---a comparative studyJan 05 2015Mar 24 2015We derive functional renormalization group schemes for Fermi systems which are based on the two-particle irreducible approach to the quantum many-body problem. In a first step, the cutoff is introduced in the non-interacting propagator as it is commonly ... More
Understanding the Josephson current through a Kondo-correlated quantum dotJan 24 2012Jun 01 2012We study the Josephson current 0-$\pi$ transition of a quantum dot tuned to the Kondo regime. The physics can be quantitatively captured by the numerically exact continuous time quantum Monte Carlo method applied to the single-impurity Anderson model ... More
The quench dynamics of a dissipative quantum system: a renormalization group studyJul 11 2013Oct 22 2013We study dissipation in a small quantum system coupled to an environment held in thermodynamic equilibrium. The relaxation dynamics of a system subject to an abrupt quench in the parameters of the underlying Hamiltonian is investigated using two complementary ... More
Morita invariance of the filter dimension and of the inequality of BernsteinOct 29 2006It is proved that the filter dimenion is Morita invariant. A direct consequence of this fact is the Morita invariance of the inequality of Bernstein: if an algebra $A$ is Morita equivalent to the ring $\CD (X)$ of differential operators on a smooth irreducible ... More
Hyperfine-induced spin relaxation of a diffusively moving carrier in low dimensions: implications for spin transport in organic semiconductorsMar 27 2015The hyperfine coupling between the spin of a charge carrier and the nuclear spin bath is a predominant channel for the carrier spin relaxation in many organic semiconductors. We theoretically investigate the hyperfine-induced spin relaxation of a carrier ... More
Neutron Diffraction and Optics of a Noncentrosymmetric Crystal. New Feasibility of a Search for Neutron EDMApr 25 2005May 03 2005Recently strong electric fields (up to 10^9 V/cm) have been discovered, which affect the neutrons moving in noncentrosymmetric crystals. Such fields allow new polarization phenomena in neutron diffraction and optics and provide, for instance, a new feasibility ... More
A remark on the Dixmier ConjectureNov 30 2018The Dixmier Conjecture says that every endomorphism of the (first) Weyl algebra $A_1$ (over a field of characteristic zero) is an automorphism, i.e., if $PQ-QP=1$ for some $P, Q \in A_1$ then $A_1 = K \langle P, Q \rangle$. The Weyl algebra $A_1$ is a ... More
Polaron spin echo envelope modulations in an organic semiconducting polymerSep 09 2016Theoretical treatment of the electron spin echo envelope modulation (ESEEM) spectra from polarons in a semiconducting $\pi$- conjugated polymer is presented. The contact hyperfine coupling and the dipolar interaction between the polaron and proton spins ... More
Decay of the rotary echoes for the spin of a nitrogen-vacancy center in diamondMar 25 2014We study dynamics of the electron spin of a nitrogen-vacancy (NV) center subjected to a strong driving field with periodically reversed direction (train of rotary echoes). We use analytical and numerical tools to analyze in detail the form and timescales ... More
Constructing the ultimate theory of grand unificationMay 16 2011Nov 02 2011In accordance with known phenomenological facts on leptons and quarks in the Standard Model as well as on the scale of neutrino masses and introducing the supersymmetry, we logically substantiate the unique composition of fundamental representation for ... More
Theory of the electron relaxation in metals excited by an ultrashort optical pumpAug 20 2013Mar 05 2014The theory of the electron relaxation in metals excited by an ultrashort optical pump is developed on the basis of the solution of the linearized kinetic equation. The kinetic equation includes both the electron-electron and the electron-phonon collision ... More