Free Majorana Fermions with Superconducting Quantum Wires and a Magnetic Impurity

Karyn Le Hur

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arXiv · 2511.03380

Free Majorana Fermions with Superconducting Quantum Wires and a Magnetic Impurity

Karyn Le Hur

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Abstract

Through the two-channel Kondo model, I address a magnetic spin-1/2 impurity interacting with a bound state of spin origin at the edge in a Luther-Emery liquid showing a spin gap in the bulk. The system presents two zero-energy Majorana fermions of magnetic origin, one on the impurity site and one at the edge. I derive the wavefunction at the edge for the produced zero-energy Majorana fermion bound state within the same formalism as topological interfaces. I present alternative versions of the quantum field theory revealing the specific pairing of the Majorana fermions in the bulk. I address local physical responses. I develop the idea that this model can be realized with a magnetic impurity bridging the gap between two s-wave superconducting wires. I show the protection of the zero-energy Majorana fermions that will be referred to as free Majorana fermions.

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Karyn Le Hur. 2025-11-05. Free Majorana Fermions with Superconducting Quantum Wires and a Magnetic Impurity. https://arxiv.org/abs/2511.03380

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