<p>Ultracold fermionic atoms in optical lattices offer pristine realizations of Hubbard models<sup><CitationRef CitationID="CR1">1</CitationRef></sup>, which are fundamental to modern condensed-matter physics<sup><CitationRef CitationID="CR2">2</CitationRef>,<CitationRef CitationID="CR3">3</CitationRef></sup>. Despite notable advancements<sup><CitationRef AdditionalCitationIDS="CR5" CitationID="CR4">4</CitationRef>–<CitationRef CitationID="CR6">6</CitationRef></sup>, the accessible temperatures in these optical lattice material analogues are still too high to address many open problems<sup><CitationRef AdditionalCitationIDS="CR8 CR9" CitationID="CR7">7</CitationRef>–<CitationRef CitationID="CR10">10</CitationRef></sup>. Here we demonstrate a several-fold reduction in temperature<sup><CitationRef CitationID="CR6">6</CitationRef>,<CitationRef AdditionalCitationIDS="CR12" CitationID="CR11">11</CitationRef>–<CitationRef CitationID="CR13">13</CitationRef></sup>, bringing large-scale quantum simulations of the Hubbard model into an entirely new regime. This is accomplished by transforming a low-entropy product state into strongly correlated states of interest via&#xa0;dynamic control of the model parameters<sup><CitationRef CitationID="CR14">14</CitationRef>,<CitationRef CitationID="CR15">15</CitationRef></sup>, which is extremely challenging to simulate classically<sup><CitationRef CitationID="CR10">10</CitationRef></sup>. At half-filling, the long-range antiferromagnetic order is close to saturation, leading to a temperature of <InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="41586_2025_9112_Article_IEq1.gif" Format="GIF" Height="22" Rendition="HTML" Resolution="72" Type="Linedraw" Width="108" /> </InlineMediaObject> <EquationSource Format="TEX">\(T/t=0.0{5}_{-0.05}^{+0.06}\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>T</mi> <mo>/</mo> <mi>t</mi> <mo>=</mo> <mn>0.0</mn> <msubsup> <mrow> <mn>5</mn> </mrow> <mrow> <mo>−</mo> <mn>0.05</mn> </mrow> <mrow> <mo>+</mo> <mn>0.06</mn> </mrow> </msubsup> </mrow> </math></EquationSource> </InlineEquation> based on comparisons with numerically exact simulations. Doped away from half-filling, it is exceedingly challenging to realize systematically accurate and predictive numerical simulations<sup><CitationRef CitationID="CR9">9</CitationRef></sup>. Importantly, we are able to use quantum simulation to identify a new pathway for achieving similarly low temperatures with doping. This is confirmed by comparing short-range spin correlations to state-of-the-art, but approximate, constrained-path auxiliary-field quantum Monte Carlo simulations<sup><CitationRef AdditionalCitationIDS="CR17" CitationID="CR16">16</CitationRef>–<CitationRef CitationID="CR18">18</CitationRef></sup>. Compared with the cuprates<sup><CitationRef CitationID="CR2">2</CitationRef>,<CitationRef CitationID="CR19">19</CitationRef>,<CitationRef CitationID="CR20">20</CitationRef></sup>, the reported temperatures correspond to a reduction from far above to below room temperature, at which physics such as the pseudogap and stripe phases may be expected<sup><CitationRef CitationID="CR3">3</CitationRef>,<CitationRef CitationID="CR19">19</CitationRef>,<CitationRef AdditionalCitationIDS="CR22 CR23" CitationID="CR21">21</CitationRef>–<CitationRef CitationID="CR24">24</CitationRef></sup>. Our work opens the door to quantum simulations that solve open questions in material science, develop synergies with numerical methods and theoretical studies, and lead to discoveries of new physics<sup><CitationRef CitationID="CR8">8</CitationRef>,<CitationRef CitationID="CR10">10</CitationRef></sup>.</p>

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A neutral-atom Hubbard quantum simulator in the cryogenic regime

  • Muqing Xu,
  • Lev Haldar Kendrick,
  • Anant Kale,
  • Youqi Gang,
  • Chunhan Feng,
  • Shiwei Zhang,
  • Aaron W. Young,
  • Martin Lebrat,
  • Markus Greiner

摘要

Ultracold fermionic atoms in optical lattices offer pristine realizations of Hubbard models1, which are fundamental to modern condensed-matter physics2,3. Despite notable advancements46, the accessible temperatures in these optical lattice material analogues are still too high to address many open problems710. Here we demonstrate a several-fold reduction in temperature6,1113, bringing large-scale quantum simulations of the Hubbard model into an entirely new regime. This is accomplished by transforming a low-entropy product state into strongly correlated states of interest via dynamic control of the model parameters14,15, which is extremely challenging to simulate classically10. At half-filling, the long-range antiferromagnetic order is close to saturation, leading to a temperature of \(T/t=0.0{5}_{-0.05}^{+0.06}\) T / t = 0.0 5 0.05 + 0.06 based on comparisons with numerically exact simulations. Doped away from half-filling, it is exceedingly challenging to realize systematically accurate and predictive numerical simulations9. Importantly, we are able to use quantum simulation to identify a new pathway for achieving similarly low temperatures with doping. This is confirmed by comparing short-range spin correlations to state-of-the-art, but approximate, constrained-path auxiliary-field quantum Monte Carlo simulations1618. Compared with the cuprates2,19,20, the reported temperatures correspond to a reduction from far above to below room temperature, at which physics such as the pseudogap and stripe phases may be expected3,19,2124. Our work opens the door to quantum simulations that solve open questions in material science, develop synergies with numerical methods and theoretical studies, and lead to discoveries of new physics8,10.