Eigenstate switching of topologically ordered states using non-Hermitian perturbations

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Hauptverfasser: Yeom, Cheol Hun, Kim, Beom Hyun, Park, Moon Jip
Format: Preprint
Veröffentlicht: 2024
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author Yeom, Cheol Hun
Kim, Beom Hyun
Park, Moon Jip
author_facet Yeom, Cheol Hun
Kim, Beom Hyun
Park, Moon Jip
contents Topologically ordered phases have robust degenerate ground states against the local perturbations, providing a promising platform for fault-tolerant quantum computation. Despite of the non-local feature of the topological order, we find that local non-Hermitian perturbations can induce the transition between the topologically ordered ground states. In this work, we study the toric code in the presence of non-Hermitian perturbations. By controlling the non-Hermiticity, we show that non-orthogonal ground states can exhibit an eigenstate coalescence and have the spectral singularity, known as an exceptional point (EP). We explore the potential of the EPs in the control of topological order. Adiabatic encircling EPs allows for the controlled switching of eigenstates, enabling dynamic manipulation between the ground state degeneracy. Interestingly, we show a property of our scheme that arbitrary strengths of local perturbations can induce the EP and eigenstate switching. Finally, we also show the orientation-dependent behavior of non-adiabatic transitions (NAT) during the dynamic encirclement around an EP. Our work shows that control of the non-Hermiticity can serve as a promising strategy for fault-tolerant quantum information processing.
format Preprint
id arxiv_https___arxiv_org_abs_2402_17280
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Eigenstate switching of topologically ordered states using non-Hermitian perturbations
Yeom, Cheol Hun
Kim, Beom Hyun
Park, Moon Jip
Mesoscale and Nanoscale Physics
Strongly Correlated Electrons
Quantum Physics
Topologically ordered phases have robust degenerate ground states against the local perturbations, providing a promising platform for fault-tolerant quantum computation. Despite of the non-local feature of the topological order, we find that local non-Hermitian perturbations can induce the transition between the topologically ordered ground states. In this work, we study the toric code in the presence of non-Hermitian perturbations. By controlling the non-Hermiticity, we show that non-orthogonal ground states can exhibit an eigenstate coalescence and have the spectral singularity, known as an exceptional point (EP). We explore the potential of the EPs in the control of topological order. Adiabatic encircling EPs allows for the controlled switching of eigenstates, enabling dynamic manipulation between the ground state degeneracy. Interestingly, we show a property of our scheme that arbitrary strengths of local perturbations can induce the EP and eigenstate switching. Finally, we also show the orientation-dependent behavior of non-adiabatic transitions (NAT) during the dynamic encirclement around an EP. Our work shows that control of the non-Hermiticity can serve as a promising strategy for fault-tolerant quantum information processing.
title Eigenstate switching of topologically ordered states using non-Hermitian perturbations
topic Mesoscale and Nanoscale Physics
Strongly Correlated Electrons
Quantum Physics
url https://arxiv.org/abs/2402.17280