Spin Signature of Polarized Majorana Zero Modes
Oral-In-person
Abstract
The motivation of this work is to understand the behavior of Majorana zero modes (MZMs) while also considering the spin degree of freedom of non-local fermionic modes to identify specific signatures of MZMs [1,2]. To achieve individual control over each spin channel, we propose a model for a hybrid qubit that consists of two U-shaped Kitaev wires with antiparallel polarizations. These wires are placed in contact with a quantum dot (QD) on both the left and right sides. This setup creates two antiparallel spin interferometers that host four MZMs at their edges. Based on this model, we suggest a measurement device similar to the one proposed by the Microsoft Azure Quantum group [3].
By analyzing the system's transitions, we can identify the key factors contributing to the formation of the characteristic zero-bias peak (ZBP). Our focus is on filtering the zero-energy transitions that arise from Majorana excitations and local Andreev reflections (LAR). Our results indicate that Majorana zero modes (MZMs) and LAR zero-energy transitions are essential for the formation of the Majorana peak. However, we also demonstrate that non-zero-energy transitions from LAR can impact the Majorana peak, potentially leading to "false positive" ZBPs in the system's conductance.
[1] Ribeiro RCB et al. Phys. Rev. B 105 205115, (2022).
[2] Bento Ribeiro R C, et al, Sci. Rep. 13 17965, (2023).
[3] M. Alcaraz Ramírez A. et al. Nature, 638:651–655, (2025).
By analyzing the system's transitions, we can identify the key factors contributing to the formation of the characteristic zero-bias peak (ZBP). Our focus is on filtering the zero-energy transitions that arise from Majorana excitations and local Andreev reflections (LAR). Our results indicate that Majorana zero modes (MZMs) and LAR zero-energy transitions are essential for the formation of the Majorana peak. However, we also demonstrate that non-zero-energy transitions from LAR can impact the Majorana peak, potentially leading to "false positive" ZBPs in the system's conductance.
[1] Ribeiro RCB et al. Phys. Rev. B 105 205115, (2022).
[2] Bento Ribeiro R C, et al, Sci. Rep. 13 17965, (2023).
[3] M. Alcaraz Ramírez A. et al. Nature, 638:651–655, (2025).
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Publication: Planned paper: Spin Signature of Polarized Majorana Zero Modes
This work constitutes part of the PHD Thesis of the first author: Tomas Sobreira.
Presenters
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Marcos Figueira
- Universidade Federal Fluminense