Feasibility of measurement-based braiding in the quasi-Majorana regime of semiconductor-superconductor heterostructures
Chuanchang Zeng, Gargee Sharma, Tudor D. Stanescu, Sumanta Tewari
DOI 10.1103/PhysRevB.102.205101 · Physical Review B
Active bibliographic source — not scientific approval
Bibliographic access preserves source history; it does not approve extracted materials or validate reported claims. Review warnings on each occurrence separately.
Abstract
We discuss the feasibility of measurement-based braiding in semiconductor-superconductor (SM-SC) heterostructures in the so-called quasi-Majorana regime—the topologically-trivial regime characterized by robust zero-bias conductance peaks (ZBCPs) that are due to partially-separated Andreev bound states (ps-ABSs). These low energy ABSs consist of component Majorana bound states (also called quasi-Majorana modes) that are spatially separated by a length scale smaller than the length of the system, in contrast with the Majorana zero modes (MZMs) emerging in the topological regime, which are separated by the length of the wire. In the quasi-Majorana regime, the ZBCPs appear to be robust to various perturbations as long as the energy splitting of the ps-ABS is less than the typical width εw of the low-energy conductance peaks (εw∼10–20μeV). However, the feasibility of measurement-based braiding depends on a different, much smaller, energy scale εm∼0.1μeV. This energy scale is given by the typical fermion parity-dependent ground state energy shift due to virtual electron transfer between the SM-SC system and a quantum dot used for parity measurements. In this paper we show that it is possible to prepare the SM-SC system in the quasi-Majorana regime with energy splittings below the εm threshold, so that measurement-based braiding is possible in principle. However, despite the apparent robustness of the corresponding ZBCPs, ps-ABSs are in reality topologically unprotected. Starting with ps-ABSs with energy below εm, we identify the maximum amplitudes of different types of (local) perturbations that are consistent with perturbation-induced energy splittings not exceeding the εm limit. We argue that measurements generating perturbations larger than the threshold amplitudes appropriate for εm cannot realize measurement-based braiding in SM-SC heterostructures in the quasi-Majorana regime. We find that, if possible at all, quantum computation using measurement-based braiding in the quasi-Majorana regime would be plagued with errors introduced by the measurement processes themselves, while such errors are significantly less likely in a scheme involving topological MZMs.
Similar papers
Majorana zero modes in semiconductor-superconductor hybrid structures: Defining topology in short and disordered nanowires through Majorana splitting
similarity 0.90Haining Pan & Sankar Das Sarma
Source status unknown — claims are unverified
Shuttling Majorana zero modes in disordered and noisy topological superconductors
similarity 0.90Bill P. Truong et al.
Source status unknown — claims are unverified
Majorana bound states in a coupled quantum-dot hybrid-nanowire system
similarity 0.89M. T. Deng et al. · 2016 · arXiv:1612.07989
Source status unknown — claims are unverified
Majorana fermions under uniaxial stress in semiconductor-superconductor heterostructures
similarity 0.89Ming Gong et al.
Source status unknown — claims are unverified
Quantum dot detects Majorana modes of both chiralities
similarity 0.89Piotr Stefański · 2023 · arXiv:2307.13366
Source status unknown — claims are unverified
Double-peak Majorana bound states in altermagnet--superconductor heterostructures
similarity 0.88Pankaj Sharma & Narayan Mohanta · 2026 · arXiv:2603.25844
Source status unknown — claims are unverified