Multi-particle content of Majorana zero-modes in the interacting p-wave wire
| Autor: | Kells, G. |
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| Rok vydání: | 2015 |
| Předmět: | |
| Zdroj: | Phys. Rev. B 92, 155434 (2015) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevB.92.155434 |
| Popis: | In the topological phase of p-wave superconductors, zero-energy Majorana quasi-particle excitations can be well-defined in the presence of local density-density interactions. Here we examine this phenomenon from the perspective of matrix representations of the commutator $\mathcal{H} =[H,\bullet]$ ,with the aim of characterising the multi-particle content of the many-body Majorana mode. To do this we show that, for quadratic fermionic systems, $\mathcal{H}$ can always be decomposed into sub-blocks that act as multi-particle generalisations of the BdG/Majorana forms that encode single-particle excitations. In this picture, density-density like interactions will break this exact excitation-number symmetry, coupling different sub-blocks and lifting degeneracies so that the eigen-operators of the commutator $\mathcal{H}$ take the form of individual eigenstate transitions $|n\rangle \langle m|$. However, the Majorana mode is special in that zero-energy transitions are not destroyed by local interactions and it becomes possible to define many-body Majoranas as the odd-parity zero-energy solutions of $\mathcal{H}$ that minimise their excitation number. This idea forms the basis for an algorithm which is used to characterise the multi-particle excitation content of the Majorana zero modes of the one-dimensional p-wave lattice model. We find that the multi-particle content of the Majorana zero-mode operators is significant even at modest interaction strengths. This has important consequences for the stability of Majorana based qubits when they are coupled to a heat bath. We will also discuss how these findings differ from previous work regarding the structure of the many-body-Majorana operators and point out that this should affect how certain experimental features are interpreted. Comment: 16 pages , 11 figures |
| Databáze: | arXiv |
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