Variational Method in Quantum Field Theory

Fuente: arXiv
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Autori principali: Hutsalyuk, Arthur, Lájer, Márton, Mussardo, Giuseppe, Stampiggi, Andrea
Natura: Preprint
Pubblicazione: 2025
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author Hutsalyuk, Arthur
Lájer, Márton
Mussardo, Giuseppe
Stampiggi, Andrea
author_facet Hutsalyuk, Arthur
Lájer, Márton
Mussardo, Giuseppe
Stampiggi, Andrea
contents We develop a variational framework for addressing two-dimensional non-integrable quantum field theories through the exact structure of their integrable counterparts. Concentrating on the $φ^4$ Landau-Ginzburg model, we use the analytical Vacuum Expectation Values and Form Factors of local operators in the sinh-Gordon theory as the foundation of a variational ansatz. In this way, we obtain controlled estimates of central physical quantities of the $φ^4$ theory - such as the finite-volume ground-state energy and the physical mass as a function of the coupling constant. The strengths of the variational methods are leveraged in combination with the Hamiltonian truncation techniques and the LeClair-Mussardo formula, which also allow to probe the accuracy of the variational approximation varying the system size. Within the weak-coupling regime, a detailed numerical analysis reveals the behaviour of the finite-volume spectrum, the ground-state energy, and the elastic part of the scattering matrix, showing how the rigorous machinery of integrable models can serve as a guiding light into the complex landscape of non-integrable quantum field dynamics.
format Preprint
id arxiv_https___arxiv_org_abs_2511_08686
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Variational Method in Quantum Field Theory
Hutsalyuk, Arthur
Lájer, Márton
Mussardo, Giuseppe
Stampiggi, Andrea
High Energy Physics - Theory
Statistical Mechanics
Quantum Physics
We develop a variational framework for addressing two-dimensional non-integrable quantum field theories through the exact structure of their integrable counterparts. Concentrating on the $φ^4$ Landau-Ginzburg model, we use the analytical Vacuum Expectation Values and Form Factors of local operators in the sinh-Gordon theory as the foundation of a variational ansatz. In this way, we obtain controlled estimates of central physical quantities of the $φ^4$ theory - such as the finite-volume ground-state energy and the physical mass as a function of the coupling constant. The strengths of the variational methods are leveraged in combination with the Hamiltonian truncation techniques and the LeClair-Mussardo formula, which also allow to probe the accuracy of the variational approximation varying the system size. Within the weak-coupling regime, a detailed numerical analysis reveals the behaviour of the finite-volume spectrum, the ground-state energy, and the elastic part of the scattering matrix, showing how the rigorous machinery of integrable models can serve as a guiding light into the complex landscape of non-integrable quantum field dynamics.
title Variational Method in Quantum Field Theory
topic High Energy Physics - Theory
Statistical Mechanics
Quantum Physics
url https://arxiv.org/abs/2511.08686