News

Move to Stockholm

As of first of July, Emil has taken up a tenured faculty position at Stockholm University, generously supported be the Wallenberg Academy Fellows program.

Jul 04, 2016 | AG Bergholtz

Quantum transport in Dirac materials: signatures of tilted and anisotropic Dirac and Weyl cones

We recently published the pre-print " Quantum transport in Dirac materials: signatures of tilted and anisotropic Dirac and Weyl cones " on arxiv.org.

Feb 12, 2015 | AG Bergholtz

Topology and Interactions in a Frustrated Slab: Tuning from Weyl Semimetals to C > 1 Fractional Chern Insulators

We recently published the article "Topology and Interactions in a Frustrated Slab: Tuning from Weyl Semimetals to C>1 Fractional Chern Insulators" in Physical Review Letters (114).

Feb 12, 2015 | AG Bergholtz

New review article

A comprehensive introduction to one of our main fields of interest, "Topological Flat Band Models and Fractional Chern Insulators" -- see the link on the left.

Aug 08, 2013 | AG Bergholtz

Conference on Corsica

"Topological Phases in Condensed Matter and Cold Atom Systems: towards quantum computations"

Jun 05, 2013 | AG Bergholtz

Talk in Oxford

Talk given at Oxford University.   Title:  "Fractional Chern insulators: High-temperature quantum Hall states and beyond"   Abstract:  A large number of recent works point to the emergence of intriguing analogues of fractional quantum Hall (FQH) states in two-dimensional lattice models due to effective interactions in nearly flat bands with Chern number C=1. In principle, this opens up a number of intriguing possibilities including lattice realizations of quantum Hall phenomena at room temperature and zero magnetic field. In this talk, I will summarize some of our recent work in the area.First, I will discuss how the most prominent fractional Chern insulators (FCIs) in C=1 bands quantitatively compare to Abelian and non-Abelian FQH states by using a Wannier basis representation of the Chern band.Second, I will give a heuristic explanation of the numerically observed FCIs and their relative stability by relating the lattice interactions to Haldane’s pseudopotentials in the continuum, as well as discuss a new interaction driven instability to incompressible states that is absent in continuum systems and is responsible for the absence of some FCIs. Third, I will discuss how flat bands with higher Chern number, C>1, naturally form in quasi-two-dimensional slabs of pyrochlore oxides and demonstrate the existence of qualitatively new correlated states within these bands.

May 22, 2013 | AG Bergholtz