Matteo Caldara, Andrea Richaud, Massimo Capone, Pietro Massignan
SciPost Phys. 15, 057 (2023) ·
published 9 August 2023
|
· pdf
We study a superfluid in a planar annulus hosting vortices with massive cores. An analytical point-vortex model shows that the massive vortices may perform radial oscillations on top of the usual uniform precession of their massless counterpart. Beyond a critical vortex mass, this oscillatory motion becomes unstable and the vortices are driven towards one of the edges. The analogy with the motion of a charged particle in a static electromagnetic field leads to the development of a plasma orbit theory that provides a description of the trajectories which remains accurate even beyond the regime of small radial oscillations. These results are confirmed by the numerical solution of coupled two-component Gross-Pitaevskii equations. The analysis is then extended to a necklace of vortices symmetrically arranged within the annulus.
Samuel Mugel, Alexandre Dauphin, Pietro Massignan, Leticia Tarruell, Maciej Lewenstein, Carlos Lobo, Alessio Celi
SciPost Phys. 3, 012 (2017) ·
published 15 August 2017
|
· pdf
Topologically non-trivial Hamiltonians with periodic boundary conditions are characterized by strictly quantized invariants.
Open questions and fundamental challenges concern their existence, and the possibility of measuring them in systems with open boundary conditions and limited spatial extension.
Here, we consider transport in Hofstadter strips, that is, two-dimensional lattices pierced by a uniform magnetic flux which extend over few sites in one of the spatial dimensions.
As we show, an atomic wavepacket exhibits a transverse displacement under the action of a weak constant force.
After one Bloch oscillation, this displacement approaches the quantized Chern number of the periodic system in the limit of vanishing tunneling along the transverse direction.
We further demonstrate that this scheme is able to map out the Chern number of ground and excited bands, and we investigate the robustness of the method in presence of both disorder and harmonic trapping.
Our results prove that topological invariants can be measured in Hofstadter strips with open boundary conditions and as few as three sites along one direction.
