Seeing Majorana fermions in time-of-flight images of staggered spinless fermions coupled by s-wave pairing
2013 (English)In: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 88, no 1, 013622- p.Article in journal (Refereed) Published
The Chern number., as a topological invariant that identifies the winding of the ground state in the particle-hole space, is a definitive theoretical signature that determines whether a given superconducting system can support Majorana zero modes. Here we show that such a winding can be faithfully identified for any superconducting system (p wave or s wave with spin-orbit coupling) through a set of time-of-flight measurements, making it a diagnostic tool also in actual cold-atom experiments. As an application, we customize the measurement scheme for a chiral topological model of spinless fermions. The proposed model only requires the experimentally accessible s-wave pairing and staggered tunneling that mimics spin-orbit coupling. By adiabatically connecting this model to Kitaev's honeycomb lattice model, we show that it gives rise to nu = +/- 1 phases, where vortices bind Majorana fermions, and nu = +/- 2 phases that emerge as the unique collective state of such vortices. Hence, the preparation of these phases and the detection of their Chern numbers provide an unambiguous signature for the presence of Majorana modes. Finally, we demonstrate that our detection procedure is resilient against most inaccuracies in experimental control parameters as well as finite temperature.
Place, publisher, year, edition, pages
2013. Vol. 88, no 1, 013622- p.
Atom and Molecular Physics and Optics
IdentifiersURN: urn:nbn:se:su:diva-92798DOI: 10.1103/PhysRevA.88.013622ISI: 000321837000021OAI: oai:DiVA.org:su-92798DiVA: diva2:642755
EPSRC; Spanish MICINN FIS2009-10061; Beca FPU AP 2009-1761; CAM research consortium QUITEMAD S2009-ESP-1594 2013-08-232013-08-202013-08-26Bibliographically approved