Dynamical Signatures of Ground‐State Degeneracy to Discriminate against Andreev Levels in a Majorana Fusion Experiment

Abstract

Detection of the fusion rule of Majora na zero‐modes is a near‐term milestone on the road to topological quantum computation. An obstacle is that the non‐deterministic fusion outcome of topological zero‐modes can be mimicked by the merging of non‐topological Andreev levels. To distinguish these two scenarios, the dynamical signatures of the ground‐state degeneracy that is the defining property of non‐Abelian anyons is searched for. By adiabatically traversing parameter space along two different pathways, one can identify ground‐state degeneracies from the breakdown of adiabaticity. It is shown that the approach can discriminate against accidental degeneracies of Andreev levels.

Confinement-induced zero-bias peaks in conventional superconductor hybrids

“…Despite the significant experimental progress, the Majorana origin of ZBCPs has been recently questioned; in great part because several works have reported ZBCPs due to quasi-zero-energy states (qZESs) at finite magnetic fields but well below the topological phase and, hence, not tied to topology . In this regard, recent theoretical efforts have suggested interesting detection protocols of MBSs [55][56][57][58][59][60][61][62][63][64][65][66][67][68][69][70][71][72][73][74], but the emergence of trivial qZESs still seems puzzling in conductance measurements.…”

Confinement-induced zero-bias peaks in conventional superconductor hybrids

“…In great part because several works have reported ZBCPs due to quasi zero-energy states (qZESs) at finite magnetic fields but well below the topological phase and, hence, not tied to topology . In this regard, recent theoretical efforts have suggested interesting detection protocols of MBSs [53][54][55][56][57][58][59][60][61][62][63][64][65][66][67][68][69][70][71][72], but the emergence of trivial qZESs still seems puzzling in conductance measurements.…”

Distinguishing trivial and topological zero energy states in long nanowire junctions

“…This he- lical regime is found at low magnetic fields and thus occurs as an inevitable interim phase before the topological phase at higher fields, which further complicates detecting MBSs. Despite recent efforts [46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65] and its large practical importance, unambiguous experimental signatures distinguishing between robust trivial ZESs in the helical regime and topological MBSs are still elusive.…”