Quantum criticality of loops with topologically constrained dynamics

Quantum fluctuating loops in 2+1 dimensions give gapless many-body states that are beyond current field theory techniques. Microscopically, these loops can be domain walls between up and down spins or chains of flipped spins similar to those in the toric code. The key feature of their dynamics is th...

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Main Authors: Zhehao Dai, Adam Nahum
Format: Article
Language:English
Published: American Physical Society 2020-07-01
Series:Physical Review Research
Online Access:http://doi.org/10.1103/PhysRevResearch.2.033051
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author Zhehao Dai
Adam Nahum
author_facet Zhehao Dai
Adam Nahum
author_sort Zhehao Dai
collection DOAJ
description Quantum fluctuating loops in 2+1 dimensions give gapless many-body states that are beyond current field theory techniques. Microscopically, these loops can be domain walls between up and down spins or chains of flipped spins similar to those in the toric code. The key feature of their dynamics is that reconnection of a pair of strands is forbidden. This happens at previously studied multicritical points between topologically nontrivial phases. We show that this topologically constrained dynamics leads to universality classes with unusual scaling properties. For example, scaling operators at these fixed points are classified by topology and not only by symmetry. We introduce the concept of the topological operator classification, provide universal scaling forms for correlation functions, and analytical and numerical results for critical exponents. We use an exact correspondence between the imaginary-time dynamics of the 2+1D quantum models and a classical Markovian dynamics for 2D classical loop models with a nonlocal Boltzmann weight (for which we also provide scaling results). We comment on open questions and generalizations of the models discussed for both quantum criticality and classical Markov processes.
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spelling doaj.art-9433d3f3db26428383db7e51d5b9ed7a2024-04-12T16:56:55ZengAmerican Physical SocietyPhysical Review Research2643-15642020-07-012303305110.1103/PhysRevResearch.2.033051Quantum criticality of loops with topologically constrained dynamicsZhehao DaiAdam NahumQuantum fluctuating loops in 2+1 dimensions give gapless many-body states that are beyond current field theory techniques. Microscopically, these loops can be domain walls between up and down spins or chains of flipped spins similar to those in the toric code. The key feature of their dynamics is that reconnection of a pair of strands is forbidden. This happens at previously studied multicritical points between topologically nontrivial phases. We show that this topologically constrained dynamics leads to universality classes with unusual scaling properties. For example, scaling operators at these fixed points are classified by topology and not only by symmetry. We introduce the concept of the topological operator classification, provide universal scaling forms for correlation functions, and analytical and numerical results for critical exponents. We use an exact correspondence between the imaginary-time dynamics of the 2+1D quantum models and a classical Markovian dynamics for 2D classical loop models with a nonlocal Boltzmann weight (for which we also provide scaling results). We comment on open questions and generalizations of the models discussed for both quantum criticality and classical Markov processes.http://doi.org/10.1103/PhysRevResearch.2.033051
spellingShingle Zhehao Dai
Adam Nahum
Quantum criticality of loops with topologically constrained dynamics
Physical Review Research
title Quantum criticality of loops with topologically constrained dynamics
title_full Quantum criticality of loops with topologically constrained dynamics
title_fullStr Quantum criticality of loops with topologically constrained dynamics
title_full_unstemmed Quantum criticality of loops with topologically constrained dynamics
title_short Quantum criticality of loops with topologically constrained dynamics
title_sort quantum criticality of loops with topologically constrained dynamics
url http://doi.org/10.1103/PhysRevResearch.2.033051
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AT adamnahum quantumcriticalityofloopswithtopologicallyconstraineddynamics