Time: 16:00 hrs 
Location: Zaal E, TNW, Delft

abstract
Upon increasing the density of electrons in a quantum wire, the system undergoes a transition from a one-dimensional to a quasi-one-dimensional state. In the absence of interactions between electrons, the transition corresponds to filling up the second subband of transverse quantization. On the other hand, strongly interacting one-dimensional electrons form a Wigner crystal, and the transition corresponds to it splitting into two chains (zigzag crystal).

In the first part of the talk, I will consider the subband transition at weak interactions. This transition is, generically, characterized by pronounced correlations as the electrons in the second band are effectively strongly interacting due to the diverging density of states close to the band bottom.

In the second part of the talk, I will address the structural properties of a quasi-one-dimensional classical Wigner crystal beyond the zigzag regime. In particular, I will concentrate on the formation of defects in the ground state that are necessary to establish a non-uniform density profile in the direction transverse to the wire.