{"title":"Variational wavefunction for Mott insulator at finite $U$ using ancilla qubits","authors":"Boran Zhou, Hui-Ke Jin, Ya-Hui Zhang","doi":"arxiv-2409.07512","DOIUrl":null,"url":null,"abstract":"The Mott regime with finite $U$ offers a promising platform for exploring\nnovel phases of matter, such as quantum spin liquids (QSL) that exhibit\nfractionalization and emergent gauge field. Here, we provide a new class\nwavefunction, dubbed ancilla wavefunction, to capture both charge and spin\n(gauge) fluctuations in QSLs at finite $U$. The ancilla wavefunction can unify\nthe Fermi liquid and Mott insulator phases with a single variation parameter\n$\\Phi$ tuning the charge gap. As $\\Phi \\rightarrow\\infty$, the wavefunction\nreduces to the Gutzwiller projected state, while at $\\Phi=U/2$, it is\neffectively equivalent to applying an inverse Schrieffer-Wolff transformation\nto the Gutzwiller projected state. This wavefunction can be numerically\nsimulated in the matrix product state representation, and its performance is\nsupported by numerical results for both one- and two-dimensional Hubbard\nmodels. Besides, we propose the possibility of a narrow regime of fractional\nFermi liquid phase between the usual Fermi liquid and the Mott insulator phases\nclose to the metal insulator transition -- a scenario typically overlooked by\nthe conventional slave rotor theory. Our ancilla wavefunction offers a novel\nconceptual framework and a powerful numerical tool for understanding Mott\nphysics.","PeriodicalId":501171,"journal":{"name":"arXiv - PHYS - Strongly Correlated Electrons","volume":"10 1","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"arXiv - PHYS - Strongly Correlated Electrons","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/arxiv-2409.07512","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
The Mott regime with finite $U$ offers a promising platform for exploring
novel phases of matter, such as quantum spin liquids (QSL) that exhibit
fractionalization and emergent gauge field. Here, we provide a new class
wavefunction, dubbed ancilla wavefunction, to capture both charge and spin
(gauge) fluctuations in QSLs at finite $U$. The ancilla wavefunction can unify
the Fermi liquid and Mott insulator phases with a single variation parameter
$\Phi$ tuning the charge gap. As $\Phi \rightarrow\infty$, the wavefunction
reduces to the Gutzwiller projected state, while at $\Phi=U/2$, it is
effectively equivalent to applying an inverse Schrieffer-Wolff transformation
to the Gutzwiller projected state. This wavefunction can be numerically
simulated in the matrix product state representation, and its performance is
supported by numerical results for both one- and two-dimensional Hubbard
models. Besides, we propose the possibility of a narrow regime of fractional
Fermi liquid phase between the usual Fermi liquid and the Mott insulator phases
close to the metal insulator transition -- a scenario typically overlooked by
the conventional slave rotor theory. Our ancilla wavefunction offers a novel
conceptual framework and a powerful numerical tool for understanding Mott
physics.