Systematic Improvement of Hamiltonian Truncation Effective Theory

Fuente: arXiv
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Autori principali: Demiray, Ekrem, Farnsworth, Kara, Houtz, Rachel
Natura: Preprint
Pubblicazione: 2025
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author Demiray, Ekrem
Farnsworth, Kara
Houtz, Rachel
author_facet Demiray, Ekrem
Farnsworth, Kara
Houtz, Rachel
contents Hamiltonian Truncation Effective Theory is a framework that aims to improve the results of Hamiltonian truncation in a systematic, order-by-order fashion using Effective Field Theory methodology. The result is a truncated effective Hamiltonian with corrections that result from a matching procedure. We establish the rigor of this method by calculating nontrival next-to-leading order corrections in a $1/E_{\rm max}$ expansion, where $E_{\rm max}$ is our effective theory cutoff. We illustrate this explicitly using 1+1D $λϕ^4$ theory, calculating corrections up to order $1/E_{\rm max}^3$. At this order, novel nonlocal contributions to the matching conditions must be incorporated. We show that by including these nonlocal terms, the error scales as $1/E_{\rm max}^4$, as expected from the Effective Field Theory power counting, providing a nontrivial check that this method is consistent and robust. We also estimate the critical coupling at which this theory flows to the 2D Ising conformal field theory and confirm that separation of scales, an essential feature of Effective Field Theory, persists at this order. These results establish Hamiltonian Truncation Effective Theory as a generic, systematic framework for improving convergence in Hamiltonian truncation and lay the groundwork to apply this method to more complex systems in higher dimensions.
format Preprint
id arxiv_https___arxiv_org_abs_2507_15941
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Systematic Improvement of Hamiltonian Truncation Effective Theory
Demiray, Ekrem
Farnsworth, Kara
Houtz, Rachel
High Energy Physics - Theory
Strongly Correlated Electrons
High Energy Physics - Lattice
High Energy Physics - Phenomenology
Hamiltonian Truncation Effective Theory is a framework that aims to improve the results of Hamiltonian truncation in a systematic, order-by-order fashion using Effective Field Theory methodology. The result is a truncated effective Hamiltonian with corrections that result from a matching procedure. We establish the rigor of this method by calculating nontrival next-to-leading order corrections in a $1/E_{\rm max}$ expansion, where $E_{\rm max}$ is our effective theory cutoff. We illustrate this explicitly using 1+1D $λϕ^4$ theory, calculating corrections up to order $1/E_{\rm max}^3$. At this order, novel nonlocal contributions to the matching conditions must be incorporated. We show that by including these nonlocal terms, the error scales as $1/E_{\rm max}^4$, as expected from the Effective Field Theory power counting, providing a nontrivial check that this method is consistent and robust. We also estimate the critical coupling at which this theory flows to the 2D Ising conformal field theory and confirm that separation of scales, an essential feature of Effective Field Theory, persists at this order. These results establish Hamiltonian Truncation Effective Theory as a generic, systematic framework for improving convergence in Hamiltonian truncation and lay the groundwork to apply this method to more complex systems in higher dimensions.
title Systematic Improvement of Hamiltonian Truncation Effective Theory
topic High Energy Physics - Theory
Strongly Correlated Electrons
High Energy Physics - Lattice
High Energy Physics - Phenomenology
url https://arxiv.org/abs/2507.15941