String operators for Cheshire strings in topological phases

Fuente: arXiv
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Main Authors: Tantivasadakarn, Nathanan, Chen, Xie
Format: Preprint
Published: 2023
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author Tantivasadakarn, Nathanan
Chen, Xie
author_facet Tantivasadakarn, Nathanan
Chen, Xie
contents Elementary point charge excitations in 3+1D topological phases can condense along a line and form a descendant excitation called the Cheshire string. Unlike the elementary flux loop excitations in the system, Cheshire strings do not have to appear as the boundary of a 2d disc and can exist on open line segments. On the other hand, Cheshire strings are different from trivial excitations that can be created with local unitaries in 0d and finite depth quantum circuits in 1d and higher. In this paper, we show that to create a Cheshire string, one needs a linear depth circuit that acts sequentially along the length of the string. Once a Cheshire string is created, its deformation, movement and fusion can be realized by finite depths circuits. This circuit depth requirement applies to all nontrivial descendant excitations including symmetry-protected topological chains and the Majorana chain.
format Preprint
id arxiv_https___arxiv_org_abs_2307_03180
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle String operators for Cheshire strings in topological phases
Tantivasadakarn, Nathanan
Chen, Xie
Strongly Correlated Electrons
Mesoscale and Nanoscale Physics
Quantum Physics
Elementary point charge excitations in 3+1D topological phases can condense along a line and form a descendant excitation called the Cheshire string. Unlike the elementary flux loop excitations in the system, Cheshire strings do not have to appear as the boundary of a 2d disc and can exist on open line segments. On the other hand, Cheshire strings are different from trivial excitations that can be created with local unitaries in 0d and finite depth quantum circuits in 1d and higher. In this paper, we show that to create a Cheshire string, one needs a linear depth circuit that acts sequentially along the length of the string. Once a Cheshire string is created, its deformation, movement and fusion can be realized by finite depths circuits. This circuit depth requirement applies to all nontrivial descendant excitations including symmetry-protected topological chains and the Majorana chain.
title String operators for Cheshire strings in topological phases
topic Strongly Correlated Electrons
Mesoscale and Nanoscale Physics
Quantum Physics
url https://arxiv.org/abs/2307.03180