SKM 2023 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 31: Topology: Majorana Physics

TT 31.4: Talk

Wednesday, March 29, 2023, 10:15–10:30, HSZ 304

Unifying the theoretical description of Andreev, Majorana, quasi-Majorana bound states — •Pasquale Marra^1,2 and Angela Nigro³ — ¹Graduate School of Mathematical Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo 153-8914, Japan — ²Department of Physics, and Research and Education Center for Natural Sciences, Keio University, 4-1-1 Hiyoshi, Yokohama, Kanagawa 223-8521, Japan — ³Dipartimento di Fisica 'E. R. Caianiello', Università degli Studi di Salerno, 84084 Fisciano (Salerno), Italy

In one-dimensional topological superconductors systems, zero-energy Majorana edge modes localize at the domain walls between topologically distinct phases, similar to the case of Jackiw-Rebbi solitons, which are solutions of the Majorana-Dirac equation on an inhomogeneous background. On the other hand, topologically trivial Andreev states below the particle-hole gap can originate from disorder or spatial inhomogeneities. Distinguishing between Majorana and Andreev states is an ongoing challenge that generated intense debate in the scientific community. Indeed, there is a continuous crossover between topologically nontrivial Majorana and trivial Andreev states induced by smooth inhomogeneities, which can occur without closing the bulk gap. Here, we describe nontrivial Majorana and Andreev bound states induced by spatial inhomogeneities and disorder, Shockley states, and Jackiw-Rebbi solitons in a unifying framework, introducing a characteristic length scale that can unambiguously distinguish between different regimes.