Almost Strong Zero Modes at Finite Temperature

Fuente: arXiv
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Main Authors: Tausendpfund, Niklas, Mitra, Aditi, Rizzi, Matteo
Format: Preprint
Published: 2025
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author Tausendpfund, Niklas
Mitra, Aditi
Rizzi, Matteo
author_facet Tausendpfund, Niklas
Mitra, Aditi
Rizzi, Matteo
contents Interacting fermionic chains exhibit extended regions of topological degeneracy of their ground states as a result of the presence of Majorana or parafermionic zero modes localized at the edges. In the opposite limit of infinite temperature, the corresponding non-integrable spin chains, obtained via generalized Jordan-Wigner mapping, are known to host so-called Almost Strong Zero Modes, which are long-lived with respect to any bulk excitations. Here, we study the fairly unexplored territory that bridges these two extreme cases of zero and infinite temperature. We blend two established techniques for states, the Lanczos series expansion and a tensor network ansatz, uplifting them to the level of operator algebra. This allows us to efficiently simulate large system sizes for arbitrarily long timescales and to extract the temperature-dependent decay rates. We observe that for the Kitaev-Hubbard model, the decay rate of the edge mode depends exponentially on the inverse temperature $β$, and on an effective energy scale $Δ_{\rm eff}$ that is greater than the thermodynamic gap of the system $Δ$.
format Preprint
id arxiv_https___arxiv_org_abs_2501_11121
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Almost Strong Zero Modes at Finite Temperature
Tausendpfund, Niklas
Mitra, Aditi
Rizzi, Matteo
Strongly Correlated Electrons
Quantum Physics
Interacting fermionic chains exhibit extended regions of topological degeneracy of their ground states as a result of the presence of Majorana or parafermionic zero modes localized at the edges. In the opposite limit of infinite temperature, the corresponding non-integrable spin chains, obtained via generalized Jordan-Wigner mapping, are known to host so-called Almost Strong Zero Modes, which are long-lived with respect to any bulk excitations. Here, we study the fairly unexplored territory that bridges these two extreme cases of zero and infinite temperature. We blend two established techniques for states, the Lanczos series expansion and a tensor network ansatz, uplifting them to the level of operator algebra. This allows us to efficiently simulate large system sizes for arbitrarily long timescales and to extract the temperature-dependent decay rates. We observe that for the Kitaev-Hubbard model, the decay rate of the edge mode depends exponentially on the inverse temperature $β$, and on an effective energy scale $Δ_{\rm eff}$ that is greater than the thermodynamic gap of the system $Δ$.
title Almost Strong Zero Modes at Finite Temperature
topic Strongly Correlated Electrons
Quantum Physics
url https://arxiv.org/abs/2501.11121