Excitation spectrum of Mott shells in optical lattices (2009)
Lühmann, Dirk-Sören, Bongs, Kai, Pfannkuche, Daniela
We theoretically study the excitation spectrum of confined macroscopic optical lattices in the Mott-insulating limit. For large systems, a fast numerical method is proposed to calculate the ground...
Krueger, Benjamin, Najafi, Massoud, Bohlens, Stellan, Froemter, Robert, Moeller, Dietmar P. F., Pfannkuche, Daniela
The strength of the non-adiabatic spin torque is currently under strong debate, as its value differs by orders of magnitude as well in theoretical predictions as in measurements. Here, a measurement...
Electron spin relaxation in GaAs quantum dot systems - The role of the hyperfine interaction (2007)
Voss, Johannes, Pfannkuche, Daniela
We present numerical results for electron spin relaxation rates for single and laterally coupled double GaAs quantum dots in a perpendicular magnetic field. As source of spin relaxation we consider...
Self-Trapping of Bosons and Fermions in Optical Lattices (2007)
Lühmann, Dirk-Sören, Bongs, Kai, Sengstock, Klaus, Pfannkuche, Daniela
We theoretically investigate the enhanced localization of bosonic atoms by fermionic atoms in three-dimensional optical lattices and find a self-trapping of the bosons for attractive boson-fermion...
Becker, Daniel, Pfannkuche, Daniela
Non-equilibrium transport through a quantum dot with one spin-split single-particle level is studied in the cotunneling regime at low temperatures. The Coulomb diamond can be subdivided into parts...
Localization and delocalization of ultracold bosonic atoms in finite optical lattices (2007)
Lühmann, Dirk-Sören, Bongs, Kai, Sengstock, Klaus, Pfannkuche, Daniela
We study bosonic atoms in small optical lattices by exact diagonalization and observe a striking similarity to the superfluid to Mott insulator transition in macroscopic systems. The momentum...
Harmonic oscillator model for current- and field-driven magnetic vortices (2007)
Krueger, Benjamin, Drews, Andre, Bolte, Markus, Merkt, Ulrich, Pfannkuche, Daniela, Meier, Guido
In experiments the distinction between spin-torque and Oersted-field driven magnetization dynamics is still an open problem. Here, the gyroscopic motion of current- and field-driven magnetic vortices...
Exact Solution of Strongly Interacting Quasi-One-Dimensional Spinor Bose Gases (2007)
Deuretzbacher, Frank, Fredenhagen, Klaus, Becker, Daniel, Bongs, Kai, Sengstock, Klaus, Pfannkuche, Daniela
We present an exact analytical solution of the fundamental system of quasi-one-dimensional spin-1 bosons with infinite delta-repulsion. The eigenfunctions are constructed from the wave functions of...
Heteronuclear molecules in an optical lattice: Theory and experiment (2007)
Deuretzbacher, Frank, Plassmeier, Kim, Pfannkuche, Daniela, Werner, Félix, Ospelkaus, Christian, Ospelkaus, Silke, ...
We study properties of two different atoms at a single optical lattice site at a heteronuclear atomic Feshbach resonance. We calculate the energy spectrum, the efficiency of rf association and the...
Výborný, Karel, Müller, Christian, Pfannkuche, Daniela
Using exact diagonalization we examine the response of several most prominent fractional quantum Hall states to a single local impurity. The 2/3 singlet state is found to be more inert than the...
Current-Driven Domain-Wall Dynamics in Curved Ferromagnetic Nanowires (2006)
Krueger, Benjamin, Pfannkuche, Daniela, Bolte, Markus, Meier, Guido, Merkt, Ulrich
The current-induced motion of a domain wall in a semicircle nanowire with applied Zeeman field is investigated. Starting from a micromagnetic model we derive an analytical solution which...
Deuretzbacher, Frank, Bongs, Kai, Sengstock, Klaus, Pfannkuche, Daniela
We study ground state properties of spinless, quasi one-dimensional bosons which are confined in a harmonic trap and interact via repulsive delta-potentials. We use the exact diagonalization method...
Probing level renormalization by sequential transport through double quantum dots (2005)
Wunsch, Bernhard, Braun, Matthias, König, Jürgen, Pfannkuche, Daniela
We study electron transport through double quantum dots in series. The tunnel coupling of the discrete dot levels to external leads causes a shift of their energy. This energy renormalization affects...
Isospin Blockade in Transport through Vertical Double Quantum Dots (2004)
Wunsch, Bernhard, Jacob, David, Pfannkuche, Daniela
We study the spectrum and the transport properties of two identical, vertically coupled quantum dots in a perpendicular magnetic field. We find correlation-induced energy crossings in a magnetic...
Tunneling of quasiholes in the fractional quantum Hall regime (2004)
Helias, Moritz, Pfannkuche, Daniela
The elementary low energy excitations in the fractional quantum Hall (FQH) regime are known to be fractionally charged quasiparticles and quasiholes. This work focusses on quasiholes in a finite...
Charge-localization and isospin-blockade in vertical double quantum dots (2004)
Jacob, David, Wunsch, Bernhard, Pfannkuche, Daniela
Charge localization seems unlikely to occur in two vertically coupled symmetric quantum dots even if a small bias voltage breaks the exact isospin-symmetry of the system. However for a three-electron...
Tews, Michael, Pfannkuche, Daniela
The influence of the tip-substrate bias induced electric field in a scanning-tunneling-spectroscopy experiment on charged InAs nanocrystals is studied. Calculating the ground and first excited...
Tews, Michael, Pfannkuche, Daniela
The influence of the tip-substrate bias induced electrical field in a scanning tunneling spectroscopy experiment on colloidal InAs nanocrystals has been studied. Calculating the Stark induced...
Electron interactions, classical integrability, and level statistics in quantum dots (1998)
Meza-Montes, Lilia, Ulloa, Sergio E., Pfannkuche, Daniela
The role of electronic interactions in the level structure of semiconductor quantum dots is analyzed in terms of the correspondence to the integrability of a classical system that models these...
Aspects of Coulomb interaction in semiconductor nanostructures / (1998)
Karlsruhe, University, Habil.-Schr., 1999.
The Quantum Hall Effect of Interacting Electrons in a Periodic Potential (1996)
Pfannkuche, Daniela, MacDonald, Allan H.
We consider the influence of an external periodic potential on the fractional quantum Hall effect of two-dimensional interacting electron systems. For many electrons on a torus, we find that the...
Gerhardts, Rolf R., Pfannkuche, Daniela, Gudmundsson, Vidar
We calculate the energy spectrum of an electron moving in a two-dimensional lattice which is defined by an electric potential and an applied perpendicular magnetic field modulated by a periodic...
Selection Rules for Transport Excitation Spectroscopy of Few-Electron Quantum Dots (1995)
Pfannkuche, Daniela, Ulloa, Sergio E.
Tunneling of electrons traversing a few-electron quantum dot is strongly influenced by the Coulomb interaction leading to Coulomb blockade effects and single-electron tunneling. We present...