Observing Spatial Charge and Spin Correlations in a Strongly-Interacting Fermi Gas

Fuente: arXiv
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Main Authors: Daix, Cyprien, Dixmerias, Maxime, He, Yuan-Yao, Verstraten, Joris, de Jongh, Tim, Peaudecerf, Bruno, Zhang, Shiwei, Yefsah, Tarik
Format: Preprint
Published: 2025
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author Daix, Cyprien
Dixmerias, Maxime
He, Yuan-Yao
Verstraten, Joris
de Jongh, Tim
Peaudecerf, Bruno
Zhang, Shiwei
Yefsah, Tarik
author_facet Daix, Cyprien
Dixmerias, Maxime
He, Yuan-Yao
Verstraten, Joris
de Jongh, Tim
Peaudecerf, Bruno
Zhang, Shiwei
Yefsah, Tarik
contents In this work, we explore two-dimensional attractive Fermi gases at the microscopic level by probing spatial charge and spin correlations in situ. Using atom-resolved continuum quantum gas microscopy, we directly observe fermion pairing and study the evolution of two- and three-point correlation functions as inter-spin attraction is increased. The precision of our measurement allows us to reveal nonlocal anticorrelations in the pair correlation function, fundamentally forbidden by the mean-field result based on Bardeen-Cooper-Schrieffer (BCS) theory but whose existence we confirm in exact auxiliary-field quantum Monte Carlo calculations. We demonstrate that the BCS prediction is critically deficient not only in the superfluid crossover regime but also deep in the weakly attractive side. Guided by our measurements, we find a remarkable relation between two- and three-point correlations that establishes the dominant role of pair-correlations. Finally, leveraging local single-pair losses, we independently characterize the short-range behavior of pair correlations, via the measurement of Tan's Contact, and find excellent agreement with numerical predictions. Our measurements provide an unprecedented microscopic view into two-dimensional Fermi gases and constitute a paradigm shift for future studies of strongly-correlated fermionic matter in the continuum.
format Preprint
id arxiv_https___arxiv_org_abs_2504_01885
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Observing Spatial Charge and Spin Correlations in a Strongly-Interacting Fermi Gas
Daix, Cyprien
Dixmerias, Maxime
He, Yuan-Yao
Verstraten, Joris
de Jongh, Tim
Peaudecerf, Bruno
Zhang, Shiwei
Yefsah, Tarik
Quantum Gases
Strongly Correlated Electrons
Quantum Physics
In this work, we explore two-dimensional attractive Fermi gases at the microscopic level by probing spatial charge and spin correlations in situ. Using atom-resolved continuum quantum gas microscopy, we directly observe fermion pairing and study the evolution of two- and three-point correlation functions as inter-spin attraction is increased. The precision of our measurement allows us to reveal nonlocal anticorrelations in the pair correlation function, fundamentally forbidden by the mean-field result based on Bardeen-Cooper-Schrieffer (BCS) theory but whose existence we confirm in exact auxiliary-field quantum Monte Carlo calculations. We demonstrate that the BCS prediction is critically deficient not only in the superfluid crossover regime but also deep in the weakly attractive side. Guided by our measurements, we find a remarkable relation between two- and three-point correlations that establishes the dominant role of pair-correlations. Finally, leveraging local single-pair losses, we independently characterize the short-range behavior of pair correlations, via the measurement of Tan's Contact, and find excellent agreement with numerical predictions. Our measurements provide an unprecedented microscopic view into two-dimensional Fermi gases and constitute a paradigm shift for future studies of strongly-correlated fermionic matter in the continuum.
title Observing Spatial Charge and Spin Correlations in a Strongly-Interacting Fermi Gas
topic Quantum Gases
Strongly Correlated Electrons
Quantum Physics
url https://arxiv.org/abs/2504.01885