Ground-state energy and excitation spectrum of the Lieb-Liniger model : accurate analytical results and conjectures about the exact solution

We study the ground-state properties and excitation spectrum of the Lieb-Liniger model, i.e. the one-dimensional Bose gas with repulsive contact interactions. We solve the Bethe-Ansatz equations in the thermodynamic limit by using an analytic method based on a series expansion on orthogonal polyn...

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Main Author: Guillaume Lang, Frank Hekking, Anna Minguzzi
Format: Article
Language:English
Published: SciPost 2017-07-01
Series:SciPost Physics
Online Access:https://scipost.org/SciPostPhys.3.1.003
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author Guillaume Lang, Frank Hekking, Anna Minguzzi
author_facet Guillaume Lang, Frank Hekking, Anna Minguzzi
author_sort Guillaume Lang, Frank Hekking, Anna Minguzzi
collection DOAJ
description We study the ground-state properties and excitation spectrum of the Lieb-Liniger model, i.e. the one-dimensional Bose gas with repulsive contact interactions. We solve the Bethe-Ansatz equations in the thermodynamic limit by using an analytic method based on a series expansion on orthogonal polynomials developed in \cite{Ristivojevic} and push the expansion to an unprecedented order. By a careful analysis of the mathematical structure of the series expansion, we make a conjecture for the analytic exact result at zero temperature and show that the partially resummed expressions thereby obtained compete with accurate numerical calculations. This allows us to evaluate the density of quasi-momenta, the ground-state energy, the local two-body correlation function and Tan's contact. Then, we study the two branches of the excitation spectrum. Using a general analysis of their properties and symmetries, we obtain novel analytical expressions at arbitrary interaction strength which are found to be extremely accurate in a wide range of intermediate to strong interactions.
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spelling doaj.art-bd787bacef514fc2bbeb58875c66ea1e2022-12-21T23:49:09ZengSciPostSciPost Physics2542-46532017-07-013100310.21468/SciPostPhys.3.1.003Ground-state energy and excitation spectrum of the Lieb-Liniger model : accurate analytical results and conjectures about the exact solutionGuillaume Lang, Frank Hekking, Anna MinguzziWe study the ground-state properties and excitation spectrum of the Lieb-Liniger model, i.e. the one-dimensional Bose gas with repulsive contact interactions. We solve the Bethe-Ansatz equations in the thermodynamic limit by using an analytic method based on a series expansion on orthogonal polynomials developed in \cite{Ristivojevic} and push the expansion to an unprecedented order. By a careful analysis of the mathematical structure of the series expansion, we make a conjecture for the analytic exact result at zero temperature and show that the partially resummed expressions thereby obtained compete with accurate numerical calculations. This allows us to evaluate the density of quasi-momenta, the ground-state energy, the local two-body correlation function and Tan's contact. Then, we study the two branches of the excitation spectrum. Using a general analysis of their properties and symmetries, we obtain novel analytical expressions at arbitrary interaction strength which are found to be extremely accurate in a wide range of intermediate to strong interactions.https://scipost.org/SciPostPhys.3.1.003
spellingShingle Guillaume Lang, Frank Hekking, Anna Minguzzi
Ground-state energy and excitation spectrum of the Lieb-Liniger model : accurate analytical results and conjectures about the exact solution
SciPost Physics
title Ground-state energy and excitation spectrum of the Lieb-Liniger model : accurate analytical results and conjectures about the exact solution
title_full Ground-state energy and excitation spectrum of the Lieb-Liniger model : accurate analytical results and conjectures about the exact solution
title_fullStr Ground-state energy and excitation spectrum of the Lieb-Liniger model : accurate analytical results and conjectures about the exact solution
title_full_unstemmed Ground-state energy and excitation spectrum of the Lieb-Liniger model : accurate analytical results and conjectures about the exact solution
title_short Ground-state energy and excitation spectrum of the Lieb-Liniger model : accurate analytical results and conjectures about the exact solution
title_sort ground state energy and excitation spectrum of the lieb liniger model accurate analytical results and conjectures about the exact solution
url https://scipost.org/SciPostPhys.3.1.003
work_keys_str_mv AT guillaumelangfrankhekkingannaminguzzi groundstateenergyandexcitationspectrumofthelieblinigermodelaccurateanalyticalresultsandconjecturesabouttheexactsolution