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

• URL: http://arxiv.org/abs/2504.01885v2
• Date: Mon, 20 Oct 2025 12:57:55 GMT
• Title: Observing Spatial Charge and Spin Correlations in a Strongly-Interacting Fermi Gas
• Authors: Cyprien Daix, Maxime Dixmerias, Yuan-Yao He, Joris Verstraten, Tim de Jongh, Bruno Peaudecerf, Shiwei Zhang, Tarik Yefsah,
• Abstract summary: We directly observe fermion pairing and study the evolution of two- and three-point correlation functions as inter-spin attraction is increased.<n>The precision of our measurement allows us to reveal nonlocal anticorrelations in the pair correlation function.<n>We find a remarkable relation between two- and three-point correlations that establishes the dominant role of pair-correlations.
• Score: 3.009726827853403
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: 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.

Related papers

• Probing the Fermi Sea Topology in a Quantum Gas [0.0]
  Pauli's exclusion principle forces fermions to occupy distinct quantum states.<n>Recent theory predicts that for non-interacting fermions, the Euler characteristic of a $D$-dimensional Fermi sea is encoded in its $D$+1-point density correlations.
  arXiv  Detail & Related papers  (2025-11-28T17:01:50Z)
• Interference and short-range correlation in fermionic Hubbard gases [10.8347942929137]
  interference patterns of ultracold atoms, observed after ballistic expansion from optical lattices, encode essential information about strongly correlated lattice systems.<n>We report the observation and quantitative characterization of interference patterns in low-temperature, homogeneous fermionic Hubbard gases.<n>We develop a novel method to extract first-order correlations from interference patterns, which directly reflect the short-range phase coherence of lattice fermions.
  arXiv  Detail & Related papers  (2025-07-20T08:31:29Z)
• Spatial Leggett-Garg Inequalities [0.0]
  We extend the Leggett-Garg inequality by considering three distant observers locally measuring a many-body system at three subsequent times.<n>We illustrate our proposal for a Heisenberg chain in a magnetic field, showing indeed that the first inequality-violation time scales proportionally to the distance between measuring parties.<n>In outlook, spatial Leggett-Garg inequalities constitute a new tool for analyzing the non-relativistic dynamics of many-body quantum systems.
  arXiv  Detail & Related papers  (2025-07-04T09:55:49Z)
• Measuring pair correlations in Bose and Fermi gases via atom-resolved microscopy [28.441455845282068]
  We demonstrate atom-resolved detection of itinerant bosonic $23$Na and fermionic $6$Li quantum gases. In contrast to prior work on lattice-trapped gases, here we realize microscopy of quantum gases in the continuum. Our technique opens the door to the atom-resolved study of strongly correlated quantum gases of bosons, fermions, and their mixtures.
  arXiv  Detail & Related papers  (2024-11-13T17:05:44Z)
• $n$-body anti-bunching in a degenerate Fermi gas of $^3$He* atoms [4.3075190561751]
  We use the unique single-atom detection properties of $3$He* atoms to perform simultaneous measurements of the $n$-body quantum correlations. Our results pave the way for using correlation functions to probe some of the rich physics associated with fermionic systems.
  arXiv  Detail & Related papers  (2023-12-05T23:41:00Z)
• Neural-network quantum states for ultra-cold Fermi gases [49.725105678823915]
  This work introduces a novel Pfaffian-Jastrow neural-network quantum state that includes backflow transformation based on message-passing architecture. We observe the emergence of strong pairing correlations through the opposite-spin pair distribution functions. Our findings suggest that neural-network quantum states provide a promising strategy for studying ultra-cold Fermi gases.
  arXiv  Detail & Related papers  (2023-05-15T17:46:09Z)
• Dilute neutron star matter from neural-network quantum states [58.720142291102135]
  Low-density neutron matter is characterized by the formation of Cooper pairs and the onset of superfluidity. We model this density regime by capitalizing on the expressivity of the hidden-nucleon neural-network quantum states combined with variational Monte Carlo and reconfiguration techniques.
  arXiv  Detail & Related papers  (2022-12-08T17:55:25Z)
• Tuning long-range fermion-mediated interactions in cold-atom quantum simulators [68.8204255655161]
  Engineering long-range interactions in cold-atom quantum simulators can lead to exotic quantum many-body behavior. Here, we propose several tuning knobs, accessible in current experimental platforms, that allow to further control the range and shape of the mediated interactions.
  arXiv  Detail & Related papers  (2022-03-31T13:32:12Z)
• Quantum correlations, entanglement spectrum and coherence of two-particle reduced density matrix in the Extended Hubbard Model [62.997667081978825]
  We study the ground state properties of the one-dimensional extended Hubbard model at half-filling. In particular, in the superconducting region, we obtain that the entanglement spectrum signals a transition between a dominant singlet (SS) to triplet (TS) pairing ordering in the system.
  arXiv  Detail & Related papers  (2021-10-29T21:02:24Z)
• Quantum Coherent States of Interacting Bose-Fermi Mixtures in One Dimension [68.8204255655161]
  We study two-component atomic gas mixtures in one dimension involving both bosons and fermions. We report a rich variety of coherent ground-state phases that vary with the intrinsic and relative strength of the interactions.
  arXiv  Detail & Related papers  (2021-10-26T17:52:37Z)
• Observation of Cooper Pairs in a Mesoscopic 2D Fermi Gas [0.9901115400430295]
  Cooper pairs are the key ingredient to BCS theory as the microscopic explanation of conventional superconductivity. Here, we directly observe Cooper pairs in a mesoscopic two-dimensional Fermi gas. Our mesoscopic system is closely related to the physics of nuclei, superconducting grains or quantum dots.
  arXiv  Detail & Related papers  (2021-09-23T17:29:18Z)
• Entropy Production and the Role of Correlations in Quantum Brownian Motion [77.34726150561087]
  We perform a study on quantum entropy production, different kinds of correlations, and their interplay in the driven Caldeira-Leggett model of quantum Brownian motion.
  arXiv  Detail & Related papers  (2021-08-05T13:11:05Z)
• Quantum asymmetry and noisy multi-mode interferometry [55.41644538483948]
  Quantum asymmetry is a physical resource which coincides with the amount of coherence between the eigenspaces of a generator. We show that the asymmetry may emphincrease as a result of a emphdecrease of coherence inside a degenerate subspace.
  arXiv  Detail & Related papers  (2021-07-23T07:30:57Z)
• Phase Transitions of Repulsive Two-Component Fermi Gases in Two Dimensions [0.0]
  We predict phase separations of two-dimensional Fermi gases with repulsive contact-type interactions between two spin components. We reveal a universal transition from the paramagnetic state at small repulsive interactions towards ferromagnetic density profiles. We uncover a zoo of metastable configurations that are energetically comparable to the ground-state density profiles.
  arXiv  Detail & Related papers  (2021-06-02T10:45:33Z)
• Probing eigenstate thermalization in quantum simulators via fluctuation-dissipation relations [77.34726150561087]
  The eigenstate thermalization hypothesis (ETH) offers a universal mechanism for the approach to equilibrium of closed quantum many-body systems. Here, we propose a theory-independent route to probe the full ETH in quantum simulators by observing the emergence of fluctuation-dissipation relations. Our work presents a theory-independent way to characterize thermalization in quantum simulators and paves the way to quantum simulate condensed matter pump-probe experiments.
  arXiv  Detail & Related papers  (2020-07-20T18:00:02Z)
• Exploring 2D synthetic quantum Hall physics with a quasi-periodically driven qubit [58.720142291102135]
  Quasi-periodically driven quantum systems are predicted to exhibit quantized topological properties. We experimentally study a synthetic quantum Hall effect with a two-tone drive.
  arXiv  Detail & Related papers  (2020-04-07T15:00:41Z)
• Correlation-induced steady states and limit cycles in driven dissipative quantum systems [0.0]
  We study a driven-dissipative model of spins one-half (qubits) on a lattice with nearest-neighbor interactions. We characterize the spatial structure of the correlations in the steady state, as well as their temporal dynamics.
  arXiv  Detail & Related papers  (2020-01-15T18:38:39Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.