Wolfgang Häusler

Crossover from Fermi Liquid to Wigner Molecule Behavior in Quantum Dots

The crossover from weak to strong correlations in parabolic quantum dots at zero magnetic field is studied by numerically exact path-integral Monte Carlo simulations for up to eight electrons. By the use of a multilevel blocking algorithm, the simulations are carried out free of the fermion sign problem. We obtain a universal crossover governed only by the density parameter

Interacting electrons in a one-dimensional quantum dot.

{r}_{s}

Wigner Molecules in Nanostructures

. For

INTERACTING ELECTRONS IN POLYGONAL QUANTUM DOTS

{r}_{s}g{r}_{c}

Wigner molecules in quantum dots

, the data are consistent with a Wigner molecule description, while, for

Conductance quantization and snake states in graphene magnetic waveguides

{r}_{s}l{r}_{c}

Spin blockade in non-linear transport through quantum dots

, Fermi liquid behavior is recovered. The crossover value

Rashba precession in quantum wires with interaction

{r}_{c}\ensuremath{\approx}4

Current resonances in graphene with time-dependent potential barriers.

is surprisingly small.

Tomonaga-Luttinger liquid parameters of magnetic waveguides in graphene

The spectral properties of up to four interacting electrons confined within a quasi-one-dimensional system of finite length are determined by numerical diagonalization including the spin degree of freedom. The ground-state energy is investigated as a function of the electron number and of the system length. The limitations of a description in terms of a capacitance are demonstrated. The energetically lowest-lying excitations are physically explained as vibrational and tunneling modes. The limits of a dilute, Wigner-type arrangement of the electrons, and a dense, more homogeneous charge distribution are discussed.