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REVIEW 2 major objections 4 minor 3 cited by

Microscopy of Ultracold Fermions in Optical Lattices

T0 review · 2 major / 4 minor · reviewed 2026-08-06 · deepseek-v4-flash

Pith's one-line read Single-site imaging of ultracold fermions has taken the Fermi-Hubbard model from textbook benchmark to a simulator whose lowest-temperature data no unbiased classical calculation can check.

desk verdict A competent, useful review of fermionic quantum gas microscopy; the Section 9 'discovery regime' claim is the one soft spot and should be flagged, not rejected. read the letter →

arxiv 2507.04042 v1 pith:I4633XRC submitted 2025-07-05 cond-mat.quant-gas physics.atom-ph

classification cond-mat.quant-gasphysics.atom-ph PACS 67.85.-d37.10.Jk71.10.Fd
keywords Fermi-Hubbardmodelquantumgasmicroscopyopticallatticesultracoldfermionsantiferromagnetismmagneticpolaronsentropyredistributionsimulation
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

These lecture notes argue that quantum gas microscopes have turned ultracold fermions in optical lattices into a working laboratory for the Fermi-Hubbard model, the same minimal Hamiltonian used to think about high-temperature superconductors. The authors review how single-site imaging has verified the model's antiferromagnetic insulator, visualised polarons and spin-charge separation, and measured transport such as a linear-in-temperature resistivity. Their closing claim is the sharp one: a new entropy-redistribution protocol cools the system to $T \sim 0.05t$, a temperature at which unbiased classical numerics can no longer benchmark the data. If that claim holds, the platform has crossed from verification into a discovery regime where the simulator itself is the source of new physics.

What carries the argument

The quantum gas microscope is the central instrument: a high-numerical-aperture objective images atoms pinned in a deep lattice while laser cooling keeps them from hopping, yielding fluorescence snapshots from which site occupancies are reconstructed with percent-level fidelity. Parity-projected imaging detects occupancy modulo two, and bilayer Stern-Gerlach separation distinguishes empty, spin-up, spin-down, and doublon sites. The target model is the single-band Fermi-Hubbard Hamiltonian $$\hat{H}=-t\sum_{\langle i,j\rangle,\$\sigma$}(\hat{c}^\dagger_{i,\$\sigma$}\hat{c}_{j,\$\sigma$}+\mathrm{h.c.})+U\sum_i \hat{n}_{i\uparrow}\hat{n}_{i\downarrow},$$ with $U/t$, $T/t$, and doping as the dimensionless parameters. For the discovery-regime claim, the load-bearing mechanism is entropy redistribution: a gapped region such as a Mott or band insulator holds few thermal excitations, so shaping the trapping potential with a digital micromirror device pushes entropy into a surrounding gapless metal, and a barrier then isolates the cold region before it is converted into a correlated state.

What would settle it

Repeat the same preparation sequence at a slightly higher-entropy setting where unbiased quantum Monte Carlo still converges, and compare the approximate temperature estimate against the Monte Carlo value across that boundary; a growing mismatch as the estimate drops would show the thermometer, not the physics, is producing the discovery regime.

Watch

Extended reading notes

Core claim

On the paper's own terms, the discovery is that site-resolved fluorescence imaging of a two-dimensional Fermi-Hubbard system has matured into a quantitative probe of strong correlation physics, and that the combination of box-shaped traps and entropy redistribution has pushed temperatures low enough to leave exact numerics behind. The review's load-bearing experimental programme is: prepare a degenerate two-component Fermi gas, load it into a deep optical lattice, freeze the many-body state, and read out every site's occupancy with percent-level fidelity; repeated snapshots then yield n-point charge and spin correlations directly. Across the reviewed decade this programme verified the antiferromagnetic Mott insulator, imaged geometric strings and magnetic polarons around single dopants, observed spin-charge separation in chains, measured a linear-in-$T$ resistivity consistent with strange-metal behaviour, and extended to triangular, mixed-dimensional, and Lieb lattices as well as attractive interactions. The culminating section reports that a band insulator surrounded by a metallic reservoir expels its entropy into the reservoir, and that after isolation and conversion into a correlated state the sample reaches $T \sim 0.05t$ — a regime the authors call the 'discovery regime,' where approximate numerics exist but unbiased ones do not.

Load-bearing premise

The load-bearing premise is that the entropy expelled from the band insulator stays out during the subsequent lattice rearrangements and that the approximate numerical technique used to estimate temperatures below $0.1t$ is accurate, since no unbiased calculation exists at those temperatures.

Editorial extensions

If this is right

  • In the verified regime, site-resolved snapshots benchmark against quantum Monte Carlo and linked-cluster numerics with temperature as the single free parameter, confirming the antiferromagnetic Mott insulator down to $T/t \approx 0.25$–$0.5$.
  • Snapshots of doped systems make quasiparticles visible: spin-charge separation in chains, geometric strings with length distributions matching string theory, and magnetic polarons of about two sites were all read directly from images.
  • Charge transport measured via the Nernst-Einstein relation, using a DMD-imprinted density wave to extract the diffusivity, yields a resistivity that is linear in temperature from $T/t \approx 0.3$ to $\approx 8$ — strange-metal behaviour native to the Hubbard model.
  • The entropy-cooled uniform sample of Section 9 can in principle be ramp-expanded into a different lattice geometry, so one low-entropy preparation could seed low-temperature phase diagrams of several models.
  • In the discovery regime, the nature of verification changes: approximate numerics can no longer be trusted, and internal consistency among measured correlations becomes the practical arbiter of the data.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • A natural sequel the notes do not state: run the entropy-redistribution sequence on the triangular lattice; whether kinetic-magnetism polarons survive to the lower temperature would test polaron-based pairing scenarios concretely.
  • A practical stand-in for ground truth in the discovery regime could be internal-thermometry consistency — requiring that correlation length, local moment, and compressibility each imply the same temperature.
  • Since entropy is parked in the metallic reservoir, the reservoir's own entropy per particle sets the floor; measuring the reservoir state directly would predict how much farther the protocol can cool before the buffer runs out.
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Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

2 major / 4 minor

Summary. This manuscript is a review/lecture-note article on quantum gas microscopy of ultracold fermions in optical lattices, covering the experimental realization of the Fermi-Hubbard model, site-resolved measurements of spin and charge correlations, transport, attractive systems, non-square lattice geometries, and long-range interactions. It contains no new experimental data or new derivations; its value is pedagogical and aggregative. The paper's most striking forward-looking claim appears in Sec. 9, where a recent entropy-redistribution protocol is reported to reach T ~ 0.05t at half-filling and below 0.1t after doping, a regime described as being beyond the reach of unbiased numerics. The review is generally careful and well referenced, but this central claim rests on an unpublished preprint and an unnamed approximate temperature estimate, and the paper contains a concrete algebraic error in the attractive-repulsive mapping of Sec. 6.

Significance. If the Sec. 9 claim is correct, the review identifies a genuine transition from benchmarking to discovery in ultracold-atom quantum simulation, which would be significant for the field. The paper's strengths are its broad but coherent coverage, clear pedagogical derivations of superexchange and the Chevy polaron wavefunction, up-to-date treatment of programmable lattices, triangular Hubbard systems, Rydberg dressing and dipolar molecules, and an honest discussion of verification challenges in Sec. 10. However, because the review contains no original data or derivations, its contribution stands or falls on the accuracy of its presentation and the reliability of the results it chooses to elevate; the unsupported temperature claim and the Eq. (11) error both need to be addressed before the manuscript can be recommended for publication.

major comments (2)
  1. [Sec. 9 (and Abstract)] The paper's central forward-looking claim — that entropy-redistribution cooling has reached T ~ 0.05t and 'where unbiased numerics cannot be performed' — is stated with more confidence than the cited evidence supports. The text reports an entropy of ~0.025 kB per particle in the band insulator, a barrier isolation step, a site-splitting ramp, and 'comparisons to an approximate numerical technique' that 'suggested a temperature below 0.1t', but it does not identify the approximate method, give an uncertainty, or provide any quantitative check that entropy is preserved through the barrier and site-splitting steps. Since both the abstract and Sec. 10 use this result to motivate a 'discovery regime', the authors should either cite the full primary analysis with explicit temperature-systematic uncertainties and adiabaticity checks, or qualify the statement to 'temperatures for which no unbiased numerical benchmark has yet been reported'. The authors themselves note in Sec. 10 that verification in the discovery regime remains an open challenge, which is in tension with the unqualified Sec. 9 wording.
  2. [Sec. 6, Eq. (11)] Equation (11) is not correct as written. Performing the partial particle-hole transformation with c_{i↓} -> (-1)^{i_x+i_y} c†_{i↓} gives Λ H(U, μbar, h) Λ† = H(-U, h - U/2, μbar - U/2) + (h - μbar)L, where L is the number of lattice sites; the additive term is a c-number, not -(μbar - h)N with N the particle-number operator. For example, on a single site the paper's formula produces the spectrum {0, U - 2μbar, 0, -2μbar} instead of the original spectrum {0, -μbar - h, -μbar + h, U - 2μbar}, so the transformation as printed does not preserve the spectrum. The qualitative statement that doping and spin-imbalance swap roles remains correct, but the equation as stated would change the chemical potential and therefore affects the thermodynamic mapping that Section 6 relies on. This should be corrected and the surrounding text adjusted accordingly.
minor comments (4)
  1. [Sec. 9] The 'approximate numerical technique' used to assign temperatures below 0.1t is not named or referenced; please identify the method and give an estimate of its systematic bias, since the claim depends on that estimate.
  2. [References] Several key works are cited only as arXiv preprints (e.g., [97], [128], [130], [137], [143], [145], [155], [158], [159], [161], [162], [163]); where journal or published versions now exist, they should be updated to give readers stable citations.
  3. [Sec. 9 / Fig. 2] A schematic of the newer [97] protocol (band-insulator region, metallic reservoir, barrier, site-splitting ramp) would make Section 9 much easier to follow; currently only the older entropy-redistribution protocol of [48] is illustrated in Fig. 2.
  4. [Sec. 6] After correcting Eq. (11), please also check the sentence 'doping and spin-imbalance swap roles' so that the parameter mapping is stated together with the constant energy shift, since the constant matters for free-energy comparisons even though it does not affect the level-spectrum statement.

Circularity Check

0 steps flagged · score 0.0 of 10

No circular derivation: the paper is a review of external experiments, and its Sec. 9 discovery-regime claim is a reported result from a non-overlapping group, not a prediction derived from this paper's own inputs.

full rationale

This manuscript is a review/lecture-note survey of Fermi-Hubbard experiments, not a derivation or prediction paper. It contains no model that is fitted and then renamed as a prediction, no equation that is defined in terms of the quantity it claims to derive, and no uniqueness theorem imported from the authors' prior work to force a choice. The authors do cite their own experimental papers (e.g., [80], [84], [90], [92], [106], [136], [142]), but these are used as reports of previously published measurements, not as load-bearing definitions of the quantities under discussion; ordinary self-reference in a review is not circularity. The strongest forward-looking statement, in Sec. 9, attributes the entropy-redistribution protocol and the T ~ 0.05t / below-0.1t estimates to reference [97] by the Greiner group, which shares no authors with the present paper; the claim is therefore not a self-citation chain. The paper itself flags the verification problem in Sec. 10 ('One of the challenges of working with analog Fermi-Hubbard simulators in the discovery regime is verification of the data they generate'), which is an honest epistemic limitation rather than a circularity. No specific reduction of a result to its inputs can be exhibited, so the appropriate finding is no significant circularity.

Assumptions & free parameters 0 free parameters · 4 assumptions · 0 invented entities

As a review, this paper introduces no free parameters and no new entities. The axioms listed are the experimental and numerical assumptions the narrative inherits from the cited work.

assumptions (4)
  • domain assumption The site-resolved images faithfully represent the many-body state after projection, with detection infidelities at the percent level.
    All correlation measurements in Secs. 3-7 rely on fluorescence imaging and reconstruction algorithms described in Sec. 2.1.
  • domain assumption The trapped gas is accurately described by the single-band Hubbard model plus a local chemical potential (LDA), with negligible higher-band and off-site terms.
    Used throughout; the microscopic derivation in Sec. 2.2 assumes deep lattices and the local density approximation in Sec. 2.3.
  • domain assumption The entropy-distribution protocol in Sec. 9 is adiabatic enough that the low entropy of the band insulator transfers to the correlated state.
    This is the load-bearing premise for the discovery-regime claim; the paper cites [97] but gives no independent verification in these notes.
  • domain assumption The numerical benchmarks cited (determinantal QMC, NLCE, Lanczos) are unbiased and converged in the regimes where they are compared to experiment.
    The review uses agreement or disagreement with numerics as evidence in Secs. 3, 4, and 5.

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Cite this review

Pith. "Pith review of Microscopy of Ultracold Fermions in Optical Lattices." pith.science (2026). https://pith.science/paper/I4633XRC

@misc{pith2026250704042,
  author       = {Pith},
  title        = {Pith review of: Microscopy of Ultracold Fermions in Optical Lattices},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/I4633XRC}},
  note         = {Machine review of arXiv:2507.04042}
}
read the original abstract

These lecture notes review recent progress in studying the Fermi-Hubbard model using ultracold gases in optical lattices. We focus on results from quantum gas microscope experiments that have allowed site-resolved measurements of charge and spin correlations in half-filled and doped Hubbard systems, as well as direct imaging of various types of polaronic quasiparticles. We also review experiments exploring dynamical properties of the Hubbard model through transport and spectroscopy. Moving beyond the plain-vanilla square-lattice Hubbard model, we present more recent work exploring Hubbard systems with novel lattice geometries and long-range interactions that stabilize new phases. Finally, we discuss the realization of entropy distribution protocols to cool these systems to ultralow temperatures where comparison to unbiased numerics is no longer possible.

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Reference graph

Works this paper leans on

163 extracted references · 68 canonical work pages · cited by 3 Pith papers

  1. [97]

    M. Xu, L.H. Kendrick, A. Kale, Y. Gang, C. Feng, S. Zhang, A.W. Young, M. Lebrat, M. Greiner, arXiv:2502.00095 (2025)

  2. [1]

    Coleman, Introduction to many-body physics (Cambridge University Press, 2015)

    P. Coleman, Introduction to many-body physics (Cambridge University Press, 2015)

  3. [2]

    Fulde, Correlated electrons in quantum matter (World Scientific, 2012)

    P. Fulde, Correlated electrons in quantum matter (World Scientific, 2012)

  4. [3]

    Feynman, Int

    R.P. Feynman, Int. J. Theor. Phys. 21, 467 (1982)

  5. [4]

    Georgescu, S

    I.M. Georgescu, S. Ashhab, F. Nori, Rev. Mod. Phys. 86, 153 (2014)

  6. [5]

    Bloch, J

    I. Bloch, J. Dalibard, W. Zwerger, Rev. Mod. Phys. 80, 885 (2008)

  7. [6]

    Bloch, J

    I. Bloch, J. Dalibard, S. Nascimbene, Nat. Phys. 8, 267 (2012)

  8. [7]

    Gross, I

    C. Gross, I. Bloch, Science 357, 995 (2017)

Show all 163 references
  1. [8]

    Gross, W.S

    C. Gross, W.S. Bakr, Nat. Phys. 17, 1316 (2021)

  2. [9]

    Bakr, J.I

    W.S. Bakr, J.I. Gillen, A. Peng, S. F ¨olling, M. Greiner, Nature 462, 74 (2009)

  3. [10]

    W.S. Bakr, A. Peng, M.E. Tai, R. Ma, J. Simon, J.I. Gillen, S. Foelling, L. Pollet, M. Greiner, Science 329, 547 (2010)

  4. [11]

    Sherson, C

    J.F. Sherson, C. Weitenberg, M. Endres, M. Cheneau, I. Bloch, S. Kuhr, Nature467, 68 (2010)

  5. [12]

    Parsons, F

    M.F. Parsons, F. Huber, A. Mazurenko, C.S. Chiu, W. Setiawan, K. Wooley-Brown, S. Blatt, M. Greiner, Phys. Rev. Lett.114, 213002 (2015)

  6. [13]

    Cheuk, M.A

    L.W. Cheuk, M.A. Nichols, M. Okan, T. Gersdorf, V.V. Ramasesh, W.S. Bakr, T. Lompe, M.W. Zwierlein, Phys. Rev. Lett.114, 193001 (2015)

  7. [14]

    Omran, M

    A. Omran, M. Boll, T.A. Hilker, K. Kleinlein, G. Salomon, I. Bloch, C. Gross, Phys. Rev. Lett. 115, 263001 (2015)

  8. [15]

    Haller, J

    E. Haller, J. Hudson, A. Kelly, D.A. Cotta, B. Peaudecerf, G.D. Bruce, S. Kuhr, Nat. Phys. 11, 738 (2015)

  9. [16]

    G.J.A. Edge, R. Anderson, D. Jervis, D.C. McKay, R. Day, S. Trotzky, J.H. Thywissen, Phys. Rev. A 92, 063406 (2015)

  10. [17]

    Gutzwiller, Phys

    M.C. Gutzwiller, Phys. Rev. Lett. 10, 159 (1963)

  11. [18]

    Kanamori, Prog

    J. Kanamori, Prog. Theor. Phys. 30, 275 (1963)

  12. [19]

    Hubbard, Proc

    J. Hubbard, Proc. R. Soc. Lond. A 276, 238 (1963)

  13. [20]

    Bednorz, K.A

    J.G. Bednorz, K.A. M¨ uller, Z. Phys. B64, 189 (1986)

  14. [21]

    Anderson, Science 235, 1196 (1987)

    P.W. Anderson, Science 235, 1196 (1987)

  15. [22]

    Lieb, F.Y

    E.H. Lieb, F.Y. Wu, Phys. Rev. Lett. 20, 1445 (1968)

  16. [23]

    LeBlanc, A.E

    J.P. LeBlanc, A.E. Antipov, F. Becca, I.W. Bulik, G.K.L. Chan, C.M. Chung, Y. Deng, M. Ferrero, T.M. Henderson, C.A. Jim´enez-Hoyos, et al., Phys. Rev. X5, 041041 (2015)

  17. [24]

    Sch ¨afer, N

    T. Sch ¨afer, N. Wentzell, F.ˇSimkovic IV, Y.Y. He, C. Hille, M. Klett, C.J. Eckhardt, B. Arzhang, V. Harkov, F.M. Le R´egent, et al., Phys. Rev. X11, 011058 (2021)

  18. [25]

    Loh, J.E

    E.Y. Loh, J.E. Gubernatis, R.T. Scalettar, S.R. White, D.J. Scalapino, R.L. Sugar, Phys. Rev. B 41, 9301 (1990)

  19. [26]

    Georges, G

    A. Georges, G. Kotliar, W. Krauth, M.J. Rozenberg, Rev. Mod. Phys. 68, 13 (1996)

  20. [27]

    Anderson, The theory of superconductivity in the high- 𝑇𝑐 cuprate superconductors (Princeton University Press, 1997) Microscopy of Ultracold Fermions in Optical Lattices 43

    P.W. Anderson, The theory of superconductivity in the high- 𝑇𝑐 cuprate superconductors (Princeton University Press, 1997) Microscopy of Ultracold Fermions in Optical Lattices 43

  21. [28]

    Zhang, T.M

    F.C. Zhang, T.M. Rice, Phys. Rev. B 37, 3759 (1988)

  22. [29]

    Motzkau, Creative Commons Attribution license (2013)

    H. Motzkau, Creative Commons Attribution license (2013). URL https://commons. wikimedia.org/wiki/File:Cuprates_phasedigagram_en.svg

  23. [30]

    Zheng, C.M

    B.X. Zheng, C.M. Chung, P. Corboz, G. Ehlers, M.P. Qin, R.M. Noack, H. Shi, S.R. White, S. Zhang, G.K.L. Chan, Science 358, 1155 (2017)

  24. [31]

    Qin, C.M

    M. Qin, C.M. Chung, H. Shi, E. Vitali, C. Hubig, U. Schollw¨ock, S.R. White, S. Zhang, Phys. Rev. X 10, 031016 (2020)

  25. [32]

    H. Xu, C.M. Chung, M. Qin, U. Schollw ¨ock, S.R. White, S. Zhang, Science 384, eadh7691 (2024)

  26. [33]

    Weitenberg, M

    C. Weitenberg, M. Endres, J.F. Sherson, M. Cheneau, P. Schauß, T. Fukuhara, I. Bloch, S. Kuhr, Nature 471, 319 (2011)

  27. [34]

    G. Ji, M. Xu, L.H. Kendrick, C.S. Chiu, J.C. Br¨ uggenj¨ urgen, D. Greif, A. Bohrdt, F. Grusdt, E. Demler, M. Lebrat, M. Greiner, Phys. Rev. X11, 021022 (2021)

  28. [35]

    Simon, W.S

    J. Simon, W.S. Bakr, R. Ma, M.E. Tai, P.M. Preiss, M. Greiner, Nature 472, 307 (2011)

  29. [36]

    Brown, D

    P.T. Brown, D. Mitra, E. Guardado-Sanchez, P. Schauß, S.S. Kondov, E. Khatami, T. Paiva, N. Trivedi, D.A. Huse, W.S. Bakr, Science357, 1385 (2017)

  30. [37]

    Gillen, W

    J. Gillen, W. Bakr, A. Peng, P. Unterwaditzer, S. F¨olling, M. Greiner, Phys. Rev. A80, 021602 (2009)

  31. [38]

    Impertro, J.F

    A. Impertro, J.F. Wienand, S. H¨afele, H. von Raven, S. Hubele, T. Klostermann, C.R. Cabrera, I. Bloch, M. Aidelsburger, Commun. Phys.6, 166 (2023)

  32. [39]

    La Rooij, C

    A. La Rooij, C. Ulm, E. Haller, S. Kuhr, New J. Phys. 25, 083036 (2023)

  33. [40]

    Preiss, R

    P.M. Preiss, R. Ma, M.E. Tai, J. Simon, M. Greiner, Phys. Rev. A 91, 041602 (2015)

  34. [41]

    Koepsell, S

    J. Koepsell, S. Hirthe, D. Bourgund, P. Sompet, J. Vijayan, G. Salomon, C. Gross, I. Bloch, Phys. Rev. Lett.125, 010403 (2020)

  35. [42]

    Hartke, B

    T. Hartke, B. Oreg, N. Jia, M. Zwierlein, Phys. Rev. Lett. 125, 113601 (2020)

  36. [43]

    Yan, B.M

    Z.Z. Yan, B.M. Spar, M.L. Prichard, S. Chi, H.T. Wei, E. Ibarra-Garc ´ıa-Padilla, K.R.A. Hazzard, W.S. Bakr, Phys. Rev. Lett.129, 123201 (2022)

  37. [44]

    Mongkolkiattichai, L

    J. Mongkolkiattichai, L. Liu, S. Dasgupta, K.R. Hazzard, P. Schauss, arXiv:2503.05687 (2025)

  38. [45]

    Jaksch, C

    D. Jaksch, C. Bruder, J.I. Cirac, C.W. Gardiner, P. Zoller, Phys. Rev. Lett.81, 3108 (1998)

  39. [46]

    C. Chin, R. Grimm, P. Julienne, E. Tiesinga, Rev. Mod. Phys. 82, 1225 (2010)

  40. [47]

    Z¨ urn, T

    G. Z¨ urn, T. Lompe, A.N. Wenz, S. Jochim, P. Julienne, J. Hutson, Phys. Rev. Lett. 110, 135301 (2013)

  41. [48]

    Mazurenko, C.S

    A. Mazurenko, C.S. Chiu, G. Ji, M.F. Parsons, M. Kan ´asz-Nagy, R. Schmidt, F. Grusdt, E. Demler, D. Greif, M. Greiner, Nature 545, 462 (2017)

  42. [49]

    Bernier, C

    J.S. Bernier, C. Kollath, A. Georges, L. De Leo, F. Gerbier, C. Salomon, M. K¨ohl, Phys. Rev. A 79, 061601 (2009)

  43. [50]

    Liang, R.N

    J. Liang, R.N. Kohn Jr, M.F. Becker, D.J. Heinzen, Appl. Opt. 49, 1323 (2010)

  44. [51]

    Gauthier, I

    G. Gauthier, I. Lenton, N. McKay Parry, M. Baker, M. Davis, H. Rubinsztein-Dunlop, T. Neely, Optica 3, 1136 (2016)

  45. [52]

    Zupancic, P.M

    P. Zupancic, P.M. Preiss, R. Ma, A. Lukin, M. Eric Tai, M. Rispoli, R. Islam, M. Greiner, Opt. Express 24, 13881 (2016)

  46. [53]

    C.S. Chiu, G. Ji, A. Mazurenko, D. Greif, M. Greiner, Phys. Rev. Lett. 120, 243201 (2018)

  47. [54]

    J ¨ordens, N

    R. J ¨ordens, N. Strohmaier, K. G¨ unter, H. Moritz, T. Esslinger, Nature455, 204 (2008)

  48. [55]

    Schneider, L

    U. Schneider, L. Hackermuller, S. Will, T. Best, I. Bloch, T.A. Costi, R. Helmes, D. Rasch, A. Rosch, Science 322, 1520 (2008)

  49. [56]

    Greif, T

    D. Greif, T. Uehlinger, G. Jotzu, L. Tarruell, T. Esslinger, Science 340, 1307 (2013)

  50. [57]

    R. Hart, P. Duarte, T. Yang, X. Liu, T. Paiva, E. Khatami, R. Scalettar, N. Trivedi, D. Huse, R. Hulet, Nature 519, 211 (2015)

  51. [58]

    Greif, M.F

    D. Greif, M.F. Parsons, A. Mazurenko, C.S. Chiu, S. Blatt, F. Huber, G. Ji, M. Greiner, Science 351, 953 (2016)

  52. [59]

    Cheuk, M.A

    L.W. Cheuk, M.A. Nichols, K.R. Lawrence, M. Okan, H. Zhang, M.W. Zwierlein, Phys. Rev. Lett. 116, 235301 (2016)

  53. [60]

    Cheuk, M.A

    L.W. Cheuk, M.A. Nichols, K.R. Lawrence, M. Okan, H. Zhang, E. Khatami, N. Trivedi, T. Paiva, M. Rigol, M.W. Zwierlein, Science353, 1260 (2016) 44 Waseem Bakr, Zengli Ba and Max Prichard

  54. [61]

    Kale, J.H

    A. Kale, J.H. Huhn, M. Xu, L.H. Kendrick, M. Lebrat, C. Chiu, G. Ji, F. Grusdt, A. Bohrdt, M. Greiner, Phys. Rev. A106, 012428 (2022)

  55. [62]

    Shao, Y.X

    H. Shao, Y.X. Wang, D.Z. Zhu, Y.S. Zhu, H.N. Sun, S.Y. Chen, C. Zhang, Z.J. Fan, Y. Deng, X.C. Yao, Y.A. Chen, J.W. Pan, Nature632, 267 (2024)

  56. [63]

    Parsons, A

    M.F. Parsons, A. Mazurenko, C.S. Chiu, G. Ji, D. Greif, M. Greiner, Science353, 1253 (2016)

  57. [64]

    Giamarchi, Quantum physics in one dimension (Clarendon Press, 2003)

    T. Giamarchi, Quantum physics in one dimension (Clarendon Press, 2003)

  58. [65]

    Hilker, G

    T. Hilker, G. Salomon, F. Grusdt, A. Omran, M. Boll, E. Demler, I. Bloch, C. Gross, Science 357, 484 (2017)

  59. [66]

    Vijayan, P

    J. Vijayan, P. Sompet, G. Salomon, J. Koepsell, S. Hirthe, A. Bohrdt, F. Grusdt, I. Bloch, C. Gross, Science 367, 186 (2020)

  60. [67]

    Schmitt-Rink, C.M

    S. Schmitt-Rink, C.M. Varma, A.E. Ruckenstein, Phys. Rev. Lett. 60, 2793 (1988)

  61. [68]

    Shraiman, E.D

    B.I. Shraiman, E.D. Siggia, Phys. Rev. Lett. 61, 467 (1988)

  62. [69]

    Sachdev, Phys

    S. Sachdev, Phys. Rev. B 39, 12232 (1989)

  63. [70]

    Kane, P.A

    C.L. Kane, P.A. Lee, N. Read, Phys. Rev. B 39, 6880 (1989)

  64. [71]

    Dagotto, A

    E. Dagotto, A. Moreo, T. Barnes, Phys. Rev. B 40, 6721 (1989)

  65. [72]

    Grusdt, M

    F. Grusdt, M. K ´anasz-Nagy, A. Bohrdt, C.S. Chiu, G. Ji, M. Greiner, D. Greif, E. Demler, Phys. Rev. X8, 011046 (2018)

  66. [73]

    C.S. Chiu, G. Ji, A. Bohrdt, M. Xu, M. Knap, E. Demler, F. Grusdt, M. Greiner, D. Greif, Science 365, 251 (2019)

  67. [74]

    Landau, Phys

    L.D. Landau, Phys. Z. Sowjet. 3, 664 (1933)

  68. [75]

    Pekar, JETP 16, 341 (1946)

    S. Pekar, JETP 16, 341 (1946)

  69. [76]

    Koepsell, J

    J. Koepsell, J. Vijayan, P. Sompet, F. Grusdt, T.A. Hilker, E. Demler, G. Salomon, I. Bloch, C. Gross, Nature 572, 358 (2019)

  70. [77]

    Koepsell, D

    J. Koepsell, D. Bourgund, P. Sompet, S. Hirthe, A. Bohrdt, Y. Wang, F. Grusdt, E. Demler, G. Salomon, C. Gross, I. Bloch, Science 374, 82 (2021)

  71. [78]

    Le Tacon, G

    M. Le Tacon, G. Ghiringhelli, J. Chaloupka, M.M. Sala, V. Hinkov, M.W. Haverkort, M. Mi- nola, M. Bakr, K.J. Zhou, S. Blanco-Canosa, C. Monney, Y.T. Song, G.L. Sun, C.T. Lin, G.M. De Luca, M. Salluzzo, G. Khaliullin, T. Schmitt, L. Braicovich, B. Keimer, Nat. Phys.7, 725 (2011)

  72. [79]

    M.P.M. Dean, G. Dellea, R.S. Springell, F. Yakhou-Harris, K. Kummer, N.B. Brookes, X. Liu, Y.J. Sun, J. Strle, T. Schmitt, L. Braicovich, G. Ghiringhelli, I. Boˇ zovi´c, J.P. Hill, Nat. Mater. 12, 1019 (2013)

  73. [80]

    Prichard, Z

    M.L. Prichard, Z. Ba, I. Morera, B.M. Spar, D.A. Huse, E. Demler, W.S. Bakr, arXiv:2502.06757 (2025)

  74. [81]

    Schirotzek, C.H

    A. Schirotzek, C.H. Wu, A. Sommer, M.W. Zwierlein, Phys. Rev. Lett. 102, 230402 (2009)

  75. [82]

    Parish, J

    M.M. Parish, J. Levinsen, in Quantum Mixtures with Ultra-cold Atoms (IOS Press, 2025), pp. 221–245

  76. [83]

    Chevy, Phys

    F. Chevy, Phys. Rev. A 74, 063628 (2006)

  77. [84]

    Brown, D

    P.T. Brown, D. Mitra, E. Guardado-Sanchez, R. Nourafkan, A. Reymbaut, C.D. H ´ebert, S. Bergeron, A.M. Tremblay, J. Kokalj, D.A. Huse, et al., Science363, 379 (2019)

  78. [85]

    Phillips, N.E

    P.W. Phillips, N.E. Hussey, P. Abbamonte, Science 377, eabh4273 (2022)

  79. [86]

    Nichols, L.W

    M.A. Nichols, L.W. Cheuk, M. Okan, T.R. Hartke, E. Mendez, T. Senthil, E. Khatami, H. Zhang, M.W. Zwierlein, Science 363, 383 (2019)

  80. [87]

    Micnas, J

    R. Micnas, J. Ranninger, S. Robaszkiewicz, Rev. Mod. Phys. 62, 113 (1990)

  81. [88]

    Hartke, B

    T. Hartke, B. Oreg, C. Turnbaugh, N. Jia, M. Zwierlein, Science 381, 82 (2023)

  82. [89]

    A.F. Ho, M.A. Cazalilla, T. Giamarchi, Phys. Rev. A 79, 033620 (2009)

  83. [90]

    Mitra, P

    D. Mitra, P. Brown, E. Guardado-Sanchez, S. Kondov, T. Devakul, D. Huse, P. Schauß, W. Bakr, Nat. Phys.14, 173 (2018)

  84. [91]

    Damascelli, Z

    A. Damascelli, Z. Hussain, Z.X. Shen, Rev. Mod. Phys. 75, 473 (2003)

  85. [92]

    Brown, E

    P. Brown, E. Guardado-Sanchez, B. Spar, E. Huang, T. Devereaux, W. Bakr, Nat. Phys. 16, 26 (2020)

  86. [93]

    Stewart, J

    J. Stewart, J. Gaebler, D. Jin, Nature 454, 744 (2008)

  87. [94]

    M. Feld, B. Fr ¨ohlich, E. Vogt, M. Koschorreck, M. K¨ohl, Nature 480, 75 (2011)

  88. [95]

    W. Wu, M.S. Scheurer, S. Chatterjee, S. Sachdev, A. Georges, M. Ferrero, Phys. Rev. X 8, 021048 (2018) Microscopy of Ultracold Fermions in Optical Lattices 45

  89. [96]

    Chalopin, P

    T. Chalopin, P. Bojovi ´c, S. Wang, T. Franz, A. Sinha, Z. Wang, D. Bourgund, J. Obermeyer, F. Grusdt, A. Bohrdt, L. Pollet, A. Wietek, A. Georges, T. Hilker, I. Bloch, arXiv:2412.17801 (2024)

  90. [98]

    Bohrdt, D

    A. Bohrdt, D. Greif, E. Demler, M. Knap, F. Grusdt, Phys. Rev. B 97, 125117 (2018)

  91. [99]

    J. Yang, L. Liu, J. Mongkolkiattichai, P. Schauss, PRX Quantum 2, 020344 (2021)

  92. [100]

    Yamamoto, H

    R. Yamamoto, H. Ozawa, D.C. Nak, I. Nakamura, T. Fukuhara, New J. Phys. 22, 123028 (2020)

  93. [101]

    de Jongh, J

    T. de Jongh, J. Verstraten, M. Dixmerias, C. Daix, B. Peaudecerf, T. Yefsah, Phys. Rev. Lett. 134, 183403 (2025)

  94. [102]

    D. Wei, D. Adler, K. Srakaew, S. Agrawal, P. Weckesser, I. Bloch, J. Zeiher, Phys. Rev. X13, 021042 (2023)

  95. [103]

    Szasz, J

    A. Szasz, J. Motruk, Phys. Rev. B 103, 235132 (2021)

  96. [104]

    Tarruell, D

    L. Tarruell, D. Greif, T. Uehlinger, G. Jotzu, T. Esslinger, Nature 483, 302 (2012)

  97. [105]

    M. Xu, L.H. Kendrick, A. Kale, Y. Gang, G. Ji, R.T. Scalettar, M. Lebrat, M. Greiner, Nature 620, 971 (2023)

  98. [106]

    Prichard, B.M

    M.L. Prichard, B.M. Spar, I. Morera, E. Demler, Z.Z. Yan, W.S. Bakr, Nature629, 323 (2024)

  99. [107]

    Szasz, J

    A. Szasz, J. Motruk, M.P. Zaletel, J.E. Moore, Phys. Rev. X 10, 021042 (2020)

  100. [108]

    Venderley, E.A

    J. Venderley, E.A. Kim, Phys. Rev. B 100, 060506 (2019)

  101. [109]

    Z. Zhu, D. Sheng, A. Vishwanath, Phys. Rev. B 105, 205110 (2022)

  102. [110]

    Zampronio, T

    V. Zampronio, T. Macr`ı, Quantum 7, 1061 (2023)

  103. [111]

    Mongkolkiattichai, L

    J. Mongkolkiattichai, L. Liu, D. Garwood, J. Yang, P. Schauss, Phys. Rev. A 108, L061301 (2023)

  104. [112]

    Anderson, Mater

    P. Anderson, Mater. Res. Bull. 8, 153 (1973)

  105. [113]

    Y. Tang, L. Li, T. Li, Y. Xu, S. Liu, K. Barmak, K. Watanabe, T. Taniguchi, A.H. MacDonald, J. Shan, K.F. Mak, Nature 579, 353 (2020)

  106. [114]

    Ciorciaro, T

    L. Ciorciaro, T. Smolenski, I. Morera, N. Kiper, S. Hiestand, M. Kroner, Y. Zhang, K. Watan- abe, T. Taniguchi, E. Demler, et al., Nature623, 509 (2023)

  107. [115]

    Haerter, B.S

    J.O. Haerter, B.S. Shastry, Phys. Rev. Lett. 95, 087202 (2005)

  108. [116]

    Zhang, W

    S.S. Zhang, W. Zhu, C.D. Batista, Phys. Rev. B 97, 140507 (2018)

  109. [117]

    Morera, M

    I. Morera, M. Kan ´asz-Nagy, T. Smolenski, L. Ciorciaro, A. Imamo˘glu, E. Demler, Phys. Rev. Res. 5, L022048 (2023)

  110. [118]

    Davydova, Y

    M. Davydova, Y. Zhang, L. Fu, Phys. Rev. B 107, 224420 (2023)

  111. [119]

    Samajdar, R.N

    R. Samajdar, R.N. Bhatt, Phys. Rev. A 110, L021303 (2024)

  112. [120]

    Schl ¨omer, U

    H. Schl ¨omer, U. Schollw¨ock, A. Bohrdt, F. Grusdt, Phys. Rev. B110, L041117 (2024)

  113. [121]

    Nagaoka, Phys

    Y. Nagaoka, Phys. Rev. 147, 392 (1966)

  114. [122]

    Lebrat, M

    M. Lebrat, M. Xu, L.H. Kendrick, A. Kale, Y. Gang, P. Seetharaman, I. Morera, E. Khatami, E. Demler, M. Greiner, Nature 629, 317 (2024)

  115. [123]

    Z. Tao, W. Zhao, B. Shen, T. Li, P. Kn¨ uppel, K. Watanabe, T. Taniguchi, J. Shan, K.F. Mak, Nat. Phys. 20, 783 (2024)

  116. [124]

    Morera, A

    I. Morera, A. Bohrdt, W.W. Ho, E. Demler, Phys. Rev. Res. 6, 023196 (2024)

  117. [125]

    Schrieffer, X.G

    J. Schrieffer, X.G. Wen, S.C. Zhang, Phys. Rev. Lett 60, 944 (1988)

  118. [126]

    Hirthe, T

    S. Hirthe, T. Chalopin, D. Bourgund, P. Bojovi ´c, A. Bohrdt, E. Demler, F. Grusdt, I. Bloch, T. Hilker, Nature613, 463 (2023)

  119. [127]

    Bohrdt, L

    A. Bohrdt, L. Homeier, I. Bloch, E. Demler, G. Grusdt, Nat. Phys. 18, 651 (2022)

  120. [128]

    Bourgund, T

    D. Bourgund, T. Chalopin, P. Bojovi´c, H. Schl¨omer, S. Wang, T. Franz, S. Hirthe, A. Bohrdt, F. Grusdt, I. Bloch, T.A. Hilker, Nature637, 57 (2025)

  121. [129]

    H. Sun, M. Huo, X. Hu, J. Li, Y. Han, L. Tang, Z. Mao, P. Yang, B. Wang, J. Cheng, D.X. Yao, G.M. Zhang, M. Wang, Nature621, 493 (2023)

  122. [130]

    Lebrat, A

    M. Lebrat, A. Kale, L.H. Kendrick, M. Xu, Y. Gang, A. Nikolaenko, P.M. Bonetti, S. Sachdev, M. Greiner, arXiv:2404.17555 (2024)

  123. [131]

    Lieb, Phys

    E.H. Lieb, Phys. Rev. Lett. 62, 1201 (1989)

  124. [132]

    Schauß, M

    P. Schauß, M. Cheneau, M. Endres, T. Fukuhara, S. Hild, A. Omran, T. Pohl, C. Gross, S. Kuhr, I. Bloch, Nature 491, 87 (2012) 46 Waseem Bakr, Zengli Ba and Max Prichard

  125. [133]

    Henkel, R

    N. Henkel, R. Nath, T. Pohl, Phys. Rev. Lett. 104, 195302 (2010)

  126. [134]

    Johnson, S.L

    J.E. Johnson, S.L. Rolston, Phys. Rev. A 82, 033412 (2010)

  127. [135]

    Pupillo, A

    G. Pupillo, A. Micheli, M. Boninsegni, I. Lesanovsky, P. Zoller, Phys. Rev. Lett.104, 223002 (2010)

  128. [136]

    Guardado-Sanchez, B.M

    E. Guardado-Sanchez, B.M. Spar, P. Schauss, R. Belyansky, J.T. Young, P. Bienias, A.V. Gorshkov, T. Iadecola, W.S. Bakr, Phys. Rev. X11, 021036 (2021)

  129. [137]

    Weckesser, K

    P. Weckesser, K. Srakaew, T. Blatz, D. Wei, D. Adler, S. Agrawal, A. Bohrdt, I. Bloch, J. Zeiher, arXiv:2405.20128 (2024)

  130. [138]

    Chomaz, I

    L. Chomaz, I. Ferrier-Barbut, F. Ferlaino, B. Laburthe-Tolra, B.L. Lev, T. Pfau, Rep. Prog. Phys. 86, 026401 (2022)

  131. [139]

    L. Su, A. Douglas, M. Szurek, A.H. H ´ebert, A. Krahn, R. Groth, G.A. Phelps, O. Markovi´c, M. Greiner, Nat. Commun. 16, 1017 (2025)

  132. [140]

    L. Su, A. Douglas, M. Szurek, R. Groth, S.F. Ozturk, A. Krahn, A.H. H ´ebert, G.A. Phelps, S. Ebadi, S. Dickerson, F. Ferlaino, O. Markovi´c, M. Greiner, Nature 622, 724 (2023)

  133. [141]

    Langen, G

    T. Langen, G. Valtolina, D. Wang, J. Ye, Nat. Phys. 20, 702 (2024)

  134. [142]

    Christakis, J.S

    L. Christakis, J.S. Rosenberg, R. Raj, S. Chi, A. Morningstar, D.A. Huse, Z.Z. Yan, W.S. Bakr, Nature 614, 64 (2023)

  135. [143]

    Mortlock, A.P

    J.M. Mortlock, A.P. Raghuram, B.P. Maddox, P.D. Gregory, S.L. Cornish, arXiv:2506.12329 (2025)

  136. [144]

    Gorshkov, S.R

    A.V. Gorshkov, S.R. Manmana, G. Chen, J. Ye, E. Demler, M.D. Lukin, A.M. Rey, Phys. Rev. Lett. 107, 115301 (2011)

  137. [145]

    Carroll, H

    A.N. Carroll, H. Hirzler, C. Miller, D. Wellnitz, S.R. Muleady, J. Lin, K.P. Zamarski, R.R.W. Wang, J.L. Bohn, A.M. Rey, J. Ye, Science388, 381 (2025)

  138. [146]

    Lubasch, V

    M. Lubasch, V. Murg, U. Schneider, J.I. Cirac, M.C. Ba ˜nuls, Phys. Rev. Lett. 107, 165301 (2011)

  139. [147]

    Bohrdt, C.S

    A. Bohrdt, C.S. Chiu, G. Ji, M. Xu, D. Greif, M. Greiner, E. Demler, F. Grusdt, M. Knap, Nat. Phys. 15, 921 (2019)

  140. [148]

    Khatami, E

    E. Khatami, E. Guardado-Sanchez, B.M. Spar, J.F. Carrasquilla, W.S. Bakr, R.T. Scalettar, Phys. Rev. A102, 033326 (2020)

  141. [149]

    Yamamoto, J

    R. Yamamoto, J. Kobayashi, T. Kuno, K. Kato, Y. Takahashi, New J. Phys.18, 023016 (2016)

  142. [150]

    Miranda, R

    M. Miranda, R. Inoue, N. Tambo, M. Kozuma, Phys. Rev. A 96, 043626 (2017)

  143. [151]

    S. Buob, J. H ¨oschele, V. Makhalov, A. Rubio-Abadal, L. Tarruell, PRX Quantum5, 020316 (2024)

  144. [152]

    S. Taie, E. Ibarra-Garc ´ıa-Padilla, N. Nishizawa, Y. Takasu, Y. Kuno, H.T. Wei, R.T. Scalettar, K.R. Hazzard, Y. Takahashi, Nat. Phys.18, 1356 (2022)

  145. [153]

    Pasqualetti, O

    G. Pasqualetti, O. Bettermann, N. Darkwah Oppong, E. Ibarra-Garc ´ıa-Padilla, S. Dasgupta, R.T. Scalettar, K.R. Hazzard, I. Bloch, S. F¨olling, Phys. Rev. Lett.132, 083401 (2024)

  146. [154]

    Xiang, E

    J. Xiang, E. Cruz-Col ´on, C.C. Chua, W.R. Milner, J. de Hond, J.F. Fricke, W. Ketterle, Phys. Rev. Lett. 134, 183401 (2025)

  147. [155]

    R. Yao, S. Chi, M. Wang, R.J. Fletcher, M. Zwierlein, Phys. Rev. Lett. 134, 183402 (2025)

  148. [156]

    C. Daix, M. Dixmerias, Y.Y. He, J. Verstraten, T. de Jongh, B. Peaudecerf, S. Zhang, T. Yefsah, arXiv:2504.01885 (2025)

  149. [157]

    Barends, J.K

    R. Barends, J.K. L. Lamata, L. Garc ´ıa- ´Alvarez, A.G. Fowler, A. Megrant, E. Jeffrey, T.C. White, D. Sank, J.Y. Mutus, B. Campbell, Y. Chen, Z. Chen, B. Chiaro, A. Dunsworth, I.C. Hoi, C. Neill, P.J.J. O’Malley, C. Quintana, A.V. P. Roushan, J. Wenner, E. Solano, J.M. Martin...

  150. [158]

    Nigmatullin, K

    R. Nigmatullin, K. Hemery, K. Ghanem, S. Moses, D. Gresh, P. Siegfried, M. Mills, T. Gat- terman, N. Hewitt, E. Granet, H. Dreyer, arXiv:2409.06789 (2024)

  151. [159]

    Evered, M

    S.J. Evered, M. Kalinowski, A.A. Geim, T. Manovitz, D. Bluvstein, S.H. Li, N. Maskara, H. Zhou, S. Ebadi, M. Xu, J. Campo, M. Cain, S. Ostermann, S.F. Yelin, S. Sachdev, M. Greiner, V. Vuleti´c, M.D. Lukin, arXiv:2501.18554 (2025)

  152. [160]

    Gonz ´alez-Cuadra, D

    D. Gonz ´alez-Cuadra, D. Bluvstein, M. Kalinowski, R. Kaubruegger, N. Maskara, P. Naldesi, T.V. Zache, A.M. Kaufman, M.D. Lukin, H. Pichler, B. Vermersch, J. Ye, P. Zoller, Proc. Natl. Acad. Sci. 120, e2304294120 (2023) Microscopy of Ultracold Fermions in Optical Lattices 47

  153. [161]

    R. Ott, D. Gonz ´alez-Cuadra, T.V. Zache, P. Zoller, A.M. Kaufman, H. Pichler, arXiv:2412.16081 (2024)

  154. [162]

    Schuckert, E

    A. Schuckert, E. Crane, A.V. Gorshkov, M. Hafezi, M.J. Gullans, arXiv:2411.08955 (2024)

  155. [163]

    Bojovi ´c, T

    P. Bojovi ´c, T. Hilker, S. Wang, J. Obermeyer, M. Barendregt, D. Tell, T. Chalopin, P.M. Preiss, I. Bloch, T. Franz, arXiv:2506.14711 (2025)

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