4 papers
Quantum geometry and flat band Bose-Einstein condensation
Aleksi Julku, Georg M. Bruun, Päivi Törmä
We study the properties of a weakly interacting Bose-Einstein condensate (BEC) in a flat band lattice system by using multiband Bogoliubov theory, and discover fundamental connecti…
Nonlinear optical response of resonantly driven polaron-polaritons
Aleksi Julku, Miguel. A. Bastarrachea-Magnani, Arturo Camacho-Guardian +1
Exciton polaritons in two-dimensional semiconductors inside microcavities are powerful platforms to explore hybrid light-matter quantum systems. Here, we study a macroscopic cohere…
Superfluid weight and Berezinskii-Kosterlitz-Thouless transition temperature of twisted bilayer graphene
Aleksi Julku, Teemu J. Peltonen, Long Liang +2
We study superconductivity of twisted bilayer graphene with local and non-local attractive interactions. We obtain the superfluid weight and Berezinskii-Kosterlitz-Thouless (BKT) t…
Superfluid weight and Berezinskii-Kosterlitz-Thouless temperature of spin-imbalanced and spin-orbit-coupled Fulde-Ferrell phases in lattice systems
Aleksi Julku, Long Liang, Päivi Törmä
We study the superfluid weight and Berezinskii-Kosterlitz-Thouless (BKT) transition temperatures in case of exotic Fulde-Ferrell (FF) superfluid states in lattice s…