Nonperturbative dynamics of (2+1)d ϕ 4-theory from Hamiltonian truncation

Abstract We use Lightcone Conformal Truncation (LCT)—a version of Hamiltonian truncation — to study the nonperturbative, real-time dynamics of ϕ 4-theory in 2+1 dimensions. This theory has UV divergences that need to be regulated. We review how, in a Hamiltonian framework with a total energy cutoff,...

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Main Authors: Nikhil Anand, Emanuel Katz, Zuhair U. Khandker, Matthew T. Walters
Format: Article
Language:English
Published: SpringerOpen 2021-05-01
Series:Journal of High Energy Physics
Subjects:
Online Access:https://doi.org/10.1007/JHEP05(2021)190
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author Nikhil Anand
Emanuel Katz
Zuhair U. Khandker
Matthew T. Walters
author_facet Nikhil Anand
Emanuel Katz
Zuhair U. Khandker
Matthew T. Walters
author_sort Nikhil Anand
collection DOAJ
description Abstract We use Lightcone Conformal Truncation (LCT)—a version of Hamiltonian truncation — to study the nonperturbative, real-time dynamics of ϕ 4-theory in 2+1 dimensions. This theory has UV divergences that need to be regulated. We review how, in a Hamiltonian framework with a total energy cutoff, renormalization is necessarily state-dependent, and UV sensitivity cannot be canceled with standard local operator counter-terms. To overcome this problem, we present a prescription for constructing the appropriate state-dependent counterterms for (2+1)d ϕ 4-theory in lightcone quantization. We then use LCT with this counterterm prescription to study ϕ 4-theory, focusing on the ℤ2 symmetry-preserving phase. Specifically, we compute the spectrum as a function of the coupling and demonstrate the closing of the mass gap at a (scheme-dependent) critical coupling. We also compute Lorentz-invariant two-point functions, both at generic strong coupling and near the critical point, where we demonstrate IR universality and the vanishing of the trace of the stress tensor.
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spelling doaj.art-f8dd457a6dc946e8a8d355266cc3c1e12022-12-21T21:59:01ZengSpringerOpenJournal of High Energy Physics1029-84792021-05-012021517510.1007/JHEP05(2021)190Nonperturbative dynamics of (2+1)d ϕ 4-theory from Hamiltonian truncationNikhil Anand0Emanuel Katz1Zuhair U. Khandker2Matthew T. Walters3Department of Physics, McGill UniversityDepartment of Physics, Boston UniversityDepartment of Physics, Boston UniversityTheoretical Physics Department, CERNAbstract We use Lightcone Conformal Truncation (LCT)—a version of Hamiltonian truncation — to study the nonperturbative, real-time dynamics of ϕ 4-theory in 2+1 dimensions. This theory has UV divergences that need to be regulated. We review how, in a Hamiltonian framework with a total energy cutoff, renormalization is necessarily state-dependent, and UV sensitivity cannot be canceled with standard local operator counter-terms. To overcome this problem, we present a prescription for constructing the appropriate state-dependent counterterms for (2+1)d ϕ 4-theory in lightcone quantization. We then use LCT with this counterterm prescription to study ϕ 4-theory, focusing on the ℤ2 symmetry-preserving phase. Specifically, we compute the spectrum as a function of the coupling and demonstrate the closing of the mass gap at a (scheme-dependent) critical coupling. We also compute Lorentz-invariant two-point functions, both at generic strong coupling and near the critical point, where we demonstrate IR universality and the vanishing of the trace of the stress tensor.https://doi.org/10.1007/JHEP05(2021)190Conformal Field TheoryNonperturbative EffectsRenormalization GroupField Theories in Lower Dimensions
spellingShingle Nikhil Anand
Emanuel Katz
Zuhair U. Khandker
Matthew T. Walters
Nonperturbative dynamics of (2+1)d ϕ 4-theory from Hamiltonian truncation
Journal of High Energy Physics
Conformal Field Theory
Nonperturbative Effects
Renormalization Group
Field Theories in Lower Dimensions
title Nonperturbative dynamics of (2+1)d ϕ 4-theory from Hamiltonian truncation
title_full Nonperturbative dynamics of (2+1)d ϕ 4-theory from Hamiltonian truncation
title_fullStr Nonperturbative dynamics of (2+1)d ϕ 4-theory from Hamiltonian truncation
title_full_unstemmed Nonperturbative dynamics of (2+1)d ϕ 4-theory from Hamiltonian truncation
title_short Nonperturbative dynamics of (2+1)d ϕ 4-theory from Hamiltonian truncation
title_sort nonperturbative dynamics of 2 1 d ϕ 4 theory from hamiltonian truncation
topic Conformal Field Theory
Nonperturbative Effects
Renormalization Group
Field Theories in Lower Dimensions
url https://doi.org/10.1007/JHEP05(2021)190
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