# KAIST physicists propose a Josephson trijunction for generating and moving Majorana states

- Published: 2026-11-08 18:34 UTC
- Section: Digital & Computing › Quantum technology
- Tags: Majorana bound states, Josephson trijunction, topological superconductor, topological qubit, non-Abelian braiding, Majorana fusion, Josephson emission spectroscopy, topological insulator, KAIST physics
- URL: https://realtech.media/news/rt-4773259085a2f9ce82815104_kaist_physicists_propose/

**A theoretical study shows how a three-junction node in a magnetic field can create, move and fuse Majorana states, steps needed for braiding in topological qubits.**

![KAIST physicists propose a Josephson trijunction for generating and moving Majorana states](https://realtech.media/media/2026/11/e40226cbd6fd0b97.jpg)
*Mwjohnson0, Wikimedia Commons, CC BY-SA 4.0*

Researchers from the Department of Physics at the Korea Advanced Institute of Science and Technology (Daejeon, South Korea) described a way to manipulate mobile Majorana bound states. The authors are Kyungtae Kim, June-Young M. Lee, Hyeongseop Kim and H.-S. Sim. The paper was published in Nature Communications on 7 November 2026. [1] The proposed element is a trijunction: three Josephson junctions meeting on a topological insulator in a perpendicular magnetic field. [1]

Majorana bound states are zero-energy localized states in topological superconductors and obey non-Abelian braiding statistics. According to the authors, manipulating mobile states is essential for braiding them and operating topological qubits. This includes on-demand generation, propagation and fusion. [1]

## Two dynamics at the trijunction centre

The superconducting phases at the trijunction centre evolve so that they cross a boundary between topological and non-topological phase domains. Depending on which boundary is crossed, the trijunction shows one of two distinct dynamics: source/sink or path. [1]

At a source/sink boundary, two Majorana states are generated pairwise at the centre, and one of them is ejected into a Josephson junction. The reverse process can also happen: two states collide and annihilate in a pair. [1] At a path boundary, a Majorana state moves from a Josephson junction to the trijunction centre, or the other way round, without involving other Majorana states. [1]

## Fusion and braiding in a trijunction network

The authors state that these two dynamics make it possible to perform fusion and braiding of Majorana states in a network of trijunctions. [1] They illustrate this with a double trijunction setup. [1]

In that setup, according to the paper, non-Abelian state evolutions associated with Majorana states can be manipulated without dynamical control of the setup. They can be detected by Josephson emission spectroscopy. [1] The work presents a scheme for such operations; the available description does not report an experimental realisation of it.

## Sources

1. [Nature Communications](https://doi.org/10.1038/s41467-026-79077-5)

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Source: RealTech, realtech.media — https://realtech.media/news/rt-4773259085a2f9ce82815104_kaist_physicists_propose/