Probing the Fermi Sea Topology in a Quantum Gas

Fuente: arXiv
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Main Authors: Daix, Cyprien, Tam, Pok Man, Dixmerias, Maxime, Verstraten, Joris, de Jongh, Tim, Peaudecerf, Bruno, Kane, Charles L., Yefsah, Tarik
Format: Preprint
Published: 2025
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_version_ 1866911292417114112
author Daix, Cyprien
Tam, Pok Man
Dixmerias, Maxime
Verstraten, Joris
de Jongh, Tim
Peaudecerf, Bruno
Kane, Charles L.
Yefsah, Tarik
author_facet Daix, Cyprien
Tam, Pok Man
Dixmerias, Maxime
Verstraten, Joris
de Jongh, Tim
Peaudecerf, Bruno
Kane, Charles L.
Yefsah, Tarik
contents Pauli's exclusion principle forces fermions to occupy distinct quantum states, creating a filled region of momentum space at low temperature, the Fermi sea, whose topology governs the system's response to perturbations and the nature of its correlation functions. Recent theory predicts that for non-interacting fermions, the Euler characteristic of a $D$-dimensional Fermi sea -- the topological invariant that describes its shape -- is encoded in its ($D$+1)-point density correlations. Here we experimentally demonstrate this connection in a two-dimensional degenerate gas of neutral $^{6}$Li atoms using single-atom-resolved imaging. By measuring three- and four-point connected density correlations in real space, we directly extract topological invariants of the underlying Fermi sea, including the Euler characteristic. Our results are in remarkable agreement with ideal-gas predictions, despite the presence of sizeable interactions, and establish a new pathway for probing many-body topology through correlation measurements.
format Preprint
id arxiv_https___arxiv_org_abs_2511_23353
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Probing the Fermi Sea Topology in a Quantum Gas
Daix, Cyprien
Tam, Pok Man
Dixmerias, Maxime
Verstraten, Joris
de Jongh, Tim
Peaudecerf, Bruno
Kane, Charles L.
Yefsah, Tarik
Quantum Gases
Mesoscale and Nanoscale Physics
Strongly Correlated Electrons
Quantum Physics
Pauli's exclusion principle forces fermions to occupy distinct quantum states, creating a filled region of momentum space at low temperature, the Fermi sea, whose topology governs the system's response to perturbations and the nature of its correlation functions. Recent theory predicts that for non-interacting fermions, the Euler characteristic of a $D$-dimensional Fermi sea -- the topological invariant that describes its shape -- is encoded in its ($D$+1)-point density correlations. Here we experimentally demonstrate this connection in a two-dimensional degenerate gas of neutral $^{6}$Li atoms using single-atom-resolved imaging. By measuring three- and four-point connected density correlations in real space, we directly extract topological invariants of the underlying Fermi sea, including the Euler characteristic. Our results are in remarkable agreement with ideal-gas predictions, despite the presence of sizeable interactions, and establish a new pathway for probing many-body topology through correlation measurements.
title Probing the Fermi Sea Topology in a Quantum Gas
topic Quantum Gases
Mesoscale and Nanoscale Physics
Strongly Correlated Electrons
Quantum Physics
url https://arxiv.org/abs/2511.23353