Concept 31 of 42 · Interacting Topological Phases

Majorana zero modes

A Majorana operator is its own Hermitian conjugate and can describe a zero-energy boundary mode in a superconducting model.

01 / The mathematical statement
$$\gamma_j^\dagger=\gamma_j,\qquad\{\gamma_i,\gamma_j\}=2\delta_{ij}$$

What this means

A Majorana operator is its own Hermitian conjugate and can describe a zero-energy boundary mode in a superconducting model.

Alternating couplings in a one-dimensional chainWeak / strong bonds · boundary physics
Conceptual illustration; not to scale.

Deep dive: mathematical and physical mechanism

A topological superconducting wire can support end-localized Majorana zero modes. A pair forms a nonlocal fermionic degree of freedom $f=(\gamma_1+i\gamma_2)/2$. Parity constraints and spatial separation can suppress certain local perturbations.

How it appears in quantum phenomena

Semiconductor–superconductor nanowires and magnetic atom chains are investigated for candidate signatures.

Assumptions, caveats and limitations

Zero-bias peaks alone do not conclusively establish topological Majorana modes or non-Abelian braiding.

Connect the ideas

For context, see the Interacting Topological Phases topic guide and the reading references.

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