Measuring Chern numbers in Hofstadter strips
Samuel Mugel, Alexandre Dauphin, Pietro Massignan, Leticia Tarruell, Maciej Lewenstein, Carlos Lobo, Alessio Celi
SciPost Phys. 3, 012 (2017) · published 15 August 2017
- doi: 10.21468/SciPostPhys.3.2.012
- Submissions/Reports
Abstract
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.
Cited by 20
Authors / Affiliations: mappings to Contributors and Organizations
See all Organizations.- 1 2 Samuel Mugel,
- 2 Alexandre Dauphin,
- 2 3 Pietro Massignan,
- 2 Leticia Tarruell,
- 2 4 Maciej Lewenstein,
- 1 Carlos Lobo,
- 2 Alessio Celi
- 1 Institut de Ciències Fotòniques / Institute of Photonic Sciences [ICFO]
- 2 University of Southampton
- 3 Universitat Politècnica de Catalunya [UPC]
- 4 Institució Catalana de Recerca i Estudis Avançats [ICREA]
- Deutsche Forschungsgemeinschaft / German Research FoundationDeutsche Forschungsgemeinschaft [DFG]
- European Research Council [ERC]
- FP7 Information and Communication Technologies (FP7 ICT) (through Organization: European Commission [EC])
- Fundacion Cellex (through Organization: Fundació Privada Cellex)
- Generalitat de Catalunya / Government of Catalonia
- H2020 Future and Emerging Technologies (FET) (through Organization: European Commission [EC])
- Ministerio de Economía y Competitividad (MINECO) (through Organization: Ministerio de Economía, Industria y Competitividad / Ministry of Economy, Industry and Competitiveness [MINECO])
- University of Southampton