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Tricritical Ising edge modes in a Majorana-Ising ladder

University of British Columbia

While Majorana fermions remain at large as fundamental particles, they emerge in condensed matter systems with peculiar properties. Grover et al. proposed a Majorana-Ising chain model, or the GSV model, where the system undergoes a tricritical Ising transition by tuning just one parameter. In this work, we generalize this model to a ladder with inter-chain Majorana couplings. From a mean field analysis, we argue that the tricritical Ising transition will also occur with inter-chain couplings that allow the system to be gapless in the non-interacting case. More crucially, based on analysis of the interacting chain model and the non-interacting ladder model, we expect the tricritical Ising modes to appear on the edges, a feature that might persist when going to 2d. We carry out extensive DMRG calculations to verify the theory in the ladder model. Finally, we discuss possible numerical probes of a 2d model.

Text

2017-08-01

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/62467

Physics

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/