Quantum transport in strongly correlated Fermi gases

Tilman Enss

REVIEW 2 major objections 6 minor 1 cited by

Quantum transport in strongly correlated Fermi gases

T0 review · 2 major / 6 minor · reviewed 2026-08-12 · deepseek-v4-flash

Challenge this review Re-run · record.json Download PDF Read on arXiv ↗ Review JSON

Pith's one-line read The bulk viscosity of a strongly correlated Fermi gas is set by fluctuations of the local pair density, and a time-dependent scattering length reveals the resulting hydrodynamic attractor before Navier-Stokes relaxation.

desk verdict A well-written talk summary that consolidates the author's own prior results on bulk viscosity and hydrodynamic attractors; the physics is sound, but the central exponential-relaxation ansatz is not self-contained. read the letter →

arxiv 2411.13165 v2 pith:XNSXUBUC submitted 2024-11-20 cond-mat.quant-gas

Tilman Enss This is my paper · ORCID

classification cond-mat.quant-gas PACS 67.85.Lm05.60.Gg

keywords stronglycorrelatedFermigasesbulkviscositycontactcorrelationshydrodynamicattractorscatteringlengthrampquantumtransportunitarygasMaxwell-Cattaneorelaxation

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

This paper argues that transport in resonantly interacting Fermi gases is carried in important part by strongly correlated local pairs of opposite-spin fermions, not only by single-fermion quasiparticles. Its central mathematical claim is that the bulk viscosity at nonzero frequency equals the response function of the contact operator, the density of local pairs, divided by $(12\pi m a)^2$. Because the contact can be probed by changing the scattering length in time, the bulk viscosity becomes measurable even in a homogeneous fluid at rest. The same response predicts that a rapid ramp drives the system out of local equilibrium and that the dissipative bulk pressure relaxes through a single first-order differential equation, producing a universal hydrodynamic attractor that precedes Navier-Stokes hydrodynamics. If this is right, it closes a gap between fermionic kinetic theory, which misses pair correlations, and experiments that observe the contact in real time.

What carries the argument

The load-bearing object is the contact operator $\hat{C} = m^2 g_0^2 \hat{n}_\uparrow \hat{n}_\downarrow = \hat{\Delta}^\dagger \hat{\Delta}$, the local pair density, which enters the pressure through $\hat{p} = (2/3)\hat{H} + \hat{C}/(12\pi m a)$. Since conserved densities do not dissipate, the non-conserved contact fluctuation is the only piece of the pressure that can produce entropy; this yields the Kubo formula for bulk viscosity as the contact-response function. The argument is completed by approximating the bulk viscosity spectral function by a single Drude peak, $\zeta(\omega) \simeq \chi\tau/(1 - i\omega\tau)$, whose time-domain counterpart is a purely exponential contact response. Inserting that exponential response into the linear-response expression gives the relaxation equation for the bulk pressure and, for a power-law drive, the closed-form attractor solution.

What would settle it

Time-resolve the contact after a rapid jump or ramp of the scattering length in a homogeneous unitary Fermi gas with time resolution better than the bulk relaxation time $\tau_\zeta$; if the normalized bulk-pressure relaxation curves for different initial scattering lengths do not collapse onto the single attractor curve of Eq. (15), and instead show a visible non-exponential component at early times, the single-Drude-peak assumption is falsified. Alternatively, compute $\zeta(\omega)$ from a real-frequency conserving solver and check whether the $C/\omega^{3/2}$ tail changes the time-domain response.

Watch

Extended reading notes

Core claim

The paper's central discovery, on its own terms, is that pressure fluctuations in a dilute Fermi gas couple to the contact operator $\hat{C} = m^2 g_0^2 \hat{n}_\uparrow \hat{n}_\downarrow = \hat{\Delta}^\dagger \hat{\Delta}$, the regularized local pair density, and that all dissipative bulk response at $\omega > 0$ comes from contact correlations alone: $\zeta(\omega>0) = (12\pi m a)^{-2}$ times the retarded contact-response function. In the time domain, the Drude form of this response converts into exponential relaxation of the contact with bulk relaxation time $\tau_\zeta$, so the bulk pressure obeys $\tau_\zeta \dot{\pi} + \pi = -\zeta V_a$, a Maxwell-Cattaneo equation rather than the Navier-Stokes relation $\pi = -\zeta V_a$. For a power-law ramp of the inverse scattering length toward unitarity, the authors find the explicit solution $\pi(t) = \pi_\mathrm{ini}\, e^{-(t-t_\mathrm{ini})/\tau_\zeta} + c_\alpha \chi\, e^{-t/\tau_\zeta}\, \Gamma(-2\alpha, -t/\tau_\zeta)$, where the second term is an attractor independent of initial conditions. The gradient expansion around this attractor has factorially growing coefficients and is asymptotic, yet the attractor solution itself is physical, while the initial-condition term is a nonhydrodynamic mode.

Load-bearing premise

The relaxation and attractor story rests on representing the bulk viscosity spectrum as a single exponential (Drude) peak; if the high-frequency contact tail or other spectral structure contributes significantly at short times, the predicted exponential relaxation and attractor equation need modification.

Editorial extensions

If this is right

Bulk viscosity can be measured without fluid motion: ramping the scattering length and time-resolving the contact gives direct access to $\zeta(\omega)$.
At unitarity the equilibrium bulk viscosity vanishes by scale invariance, so measured bulk dissipation there is a direct probe of the pair-contact fluctuation channel.
The bulk relaxation rate $\tau_\zeta^{-1} \propto T$ is nearly density-independent and $T$-linear over a wide range, distinguishing pair-dominated damping from quasiparticle transport.
A rapid drive produces a universal attractor that is the same for different initial conditions, and Navier-Stokes hydrodynamics is recovered only as the late-time, leading-order piece of an asymptotic series.
Sound attenuation receives pair contributions that a fermionic Boltzmann equation misses, so a coupled fermion-pair kinetic theory is needed especially near unitarity.

Reading between the lines

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

Editorial inference: if the single-Drude-peak approximation is replaced by the full spectral function with its $C/\omega^{3/2}$ tail, the early-time relaxation after a sudden ramp should show a non-exponential correction; measuring that transient would directly test the single-relaxation-time assumption.
Editorial inference: the same contact-response logic may apply to other non-conserved operators entering transport coefficients, suggesting that analogous attractors could appear in spin or thermal response driven by time-dependent trap or field parameters.
Editorial inference: because $\tau_\zeta^{-1} \propto T$ and is largely density-independent, the attractor offers a way to extract this rate from a single time-resolved contact measurement without absolute calibration of viscosity.
Editorial inference: extending the coupled fermion-pair kinetic theory from the virial regime into quantum degeneracy would yield quantitative predictions for the attractor at low temperature and in the superfluid, where pair-breaking modes may modify the relaxation.

Share X Bluesky LinkedIn Reddit HN

Editorial analysis

A structured set of objections, weighed in public.

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

Desk Editor's Note

read the letter

Dear colleague,

This is a review-style summary of a talk, and it should be judged as such. What's actually new here is close to nothing: the central equations (9), (12), (14), (15) are taken from the author's earlier papers, [20], [35], [41], and from Fujii-Nishida. But as a compact synthesis, it's quite good. It spells out a clean physical story: bulk viscosity in a resonantly interacting Fermi gas is dominated by pair fluctuations, captured by the contact operator, and a time-dependent scattering length gives a practical no-moving-parts probe. The logic from the pressure operator to Eq. (9) is clear, and the connection to the hydrodynamic attractor is intellectually attractive.

The main soft spot is the one the stress-test flags: Eq. (12) turns the bulk-viscosity spectrum into a single Drude peak, which then generates the Maxwell-Cattaneo equation (14) and the attractor (15). The paper itself notes the high-frequency contact tail, ζ(ω→∞) ∼ C/ω^{3/2}, and that tail is not compatible with a purely exponential time-domain response. The paper gives no estimate of how much spectral weight the tail carries or whether it corrupts the short-time relaxation. This matters because the attractor prediction is the paper's most striking claim. That said, this is not a new flaw in this manuscript—it's a limitation in the underlying papers, and the review is honest enough to mention the tail. A reader who wants to use Eq. (15) should go back to [20] and check the numerics there.

The citation pattern is heavily self-referential, but in this case it's not a red flag, because the author is summarizing his own body of work. External references are present where appropriate.

Who is this for? Someone looking for an entry point into the bulk-viscosity/contact/attractor literature, or a referee wanting a quick overview. As a research contribution it's thin, but as a review of a specific program it's solid and well-written. I'd send it to peer review, with a referee who will check that the claims are properly attributed to the earlier papers and that the Drude-tail caveat is stated clearly (it is, but the implications are not discussed). I'd probably not cite it in my own work, since the original papers carry more weight.

Verdict: engage with it, but as a review, not as a new result.

Referee Report

2 major / 6 minor

Summary. This proceedings-style manuscript argues that bulk viscosity in strongly interacting Fermi gases is dominated by short-range pair (contact) correlations rather than fermionic quasiparticles. It recalls the Kubo formula connecting the bulk viscosity at positive frequency to the contact-response function (Eq. 9), proposes a measurement protocol based on the response to a time-dependent scattering length (Eqs. 10-11), and then assumes a single-Drude-peak form for the bulk-viscosity spectrum. Under that assumption it obtains an exponential contact response (Eq. 12), a Maxwell-Cattaneo relaxation equation for the dissipative bulk pressure (Eq. 14), and a hydrodynamic-attractor solution for a power-law ramp of the scattering length (Eq. 15). The paper closes with a prediction of a T-linear, density-independent bulk relaxation rate and with remarks on future real-frequency Luttinger-Ward computations.

Significance. If the central claims hold, the paper provides an attractive and experimentally testable route to a transport coefficient that is difficult to access in strongly correlated fermions: it identifies bulk viscosity with pair (contact) fluctuations, gives a concrete measurement protocol using a magnetic-field ramp in a stationary fluid, and presents an explicit attractor solution (Eq. 15) with a factorial asymptotic series. The paper is commendably concrete: Eq. (15) and the T-linear scaling of tau_zeta are falsifiable predictions, and the connection between the contact response and the bulk viscosity is a genuinely useful identity. The main reservation is that the quantitative attractor and relaxation claims rest on a single-Drude-peak approximation whose domain of validity is not established in the manuscript, especially because the text itself acknowledges a high-frequency contact tail with a different spectral form.

major comments (2)

[Sec. 4, Eq. (12)] The exponential response in Eq. (12) is obtained by replacing the bulk-viscosity spectral function by a single Drude peak. This is not a controlled truncation: Sec. 3 explicitly states that the spectrum also has an anomalous contact tail zeta(omega->infinity) ~ C/omega^{3/2}, which is incompatible with the 1/omega decay of a Drude form and would produce non-exponential short-time contact response. Since Eq. (14) is obtained by differentiating Eq. (12), the Maxwell-Cattaneo equation and the attractor solution (15) inherit this approximation. Please quantify the spectral weight of the tail and its effect on pi(t) for t <~ tau_zeta, especially for fast drives with omega*tau_zeta >~ 1, or state the conditions under which the tail can be neglected. Without such a bound, the central claim that the system follows the attractor before Navier-Stokes applies is not established in this manuscript.
[Sec. 4, Eq. (15)] The text refers to "the sum rule chi = zeta/tau_zeta" before Eq. (15), but for a spectrum that contains both a Drude peak and a omega^{-3/2} tail this identification needs justification. If chi is meant to be the full static susceptibility or the total spectral weight, the tail contributes to it and chi = zeta/tau_zeta is not exact; if chi is only the Drude weight, calling it a sum rule is misleading and the attractor solution depends on an extra parameter. Please clarify the definition of chi and its relation to the full spectrum.

minor comments (6)

[Sec. 4, Fig. 1] The figure caption uses c(t) - c_eq(t) for the normalized bulk pressure pi(t)/chi, but the symbol c is not defined in the text; this should be clarified.
[Sec. 4, Fig. 1 caption] The word "attoractor" in the figure legend is a typo and should read "attractor".
[Sec. 3, Eqs. (5) and (9)] The integrals over d^d x d t are written without explicit limits or a statement of the causal i0 prescription; for consistency with Eq. (4), please make the notation uniform.
[Sec. 3.1] The statement that modulating a(t) "maps out the frequency dependence" of the bulk viscosity should acknowledge that the extraction of zeta(omega) from the measured contact response requires inverting the linear-response relation (11), with the usual limitations on bandwidth and drive amplitude.
[Sec. 2] The discussion of Pauli blocking enhancing the cross section near resonance is cited to Refs. [19,24] without specifying which equation or calculation is meant; a more precise pointer would help the reader.
[References] Reference [21] is an arXiv preprint; if it has been published in the meantime, the reference should be updated.

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: the bulk-viscosity/contact reduction follows from Kubo formulas with external support, and the Maxwell–Cattaneo equation is derived explicitly from the stated Drude approximation, not from a fitted target.

full rationale

The paper's derivation chain is not circular. The Kubo formula (5) and the pressure operator (6) are standard; projecting out conserved components gives Eq. (9), with the bulk viscosity at positive frequency expressed through the contact response, a reduction cited to several independent groups ([32], [34], [36]) as well as the author's own [35]. The exponential contact response in Eq. (12) is introduced explicitly as the time-domain form of the Drude peak found in the microscopic Luttinger-Ward computation [35]; the text immediately notes the distinct high-frequency contact tail, so the approximation is not disguised. Equations (14) and (15) are mathematical consequences of differentiating and integrating Eq. (12) under the stated linear-response and power-law-drive assumptions, and the attractor solution is given explicitly rather than renamed from fitted data. The heavy reliance on the author's prior work [20, 35, 41] is a citation of parameter-free microscopic computations with stated assumptions, not a fit to the predicted relaxation dynamics; the contact response to a scattering-length ramp is an experimentally falsifiable external benchmark. The skeptical concern about the omitted ω^{-3/2} tail is a quantitative accuracy and correctness issue, not a circular reduction of the derivation to its own inputs.

Assumptions & free parameters 1 free parameters · 5 assumptions · 0 invented entities

The framework uses standard thermodynamic and many-body identities plus the Drude approximation for the bulk spectral function. No new entities are introduced.

free parameters (1)

Bulk relaxation time τζ = Not specified; in [35] it is computed via Luttinger-Ward theory.
The single-exponential contact response (12) and the relaxation equation (14) depend on a single timescale τζ that is not derived within this paper and is used as an input.

assumptions (5)

standard math Kubo formulas relate transport coefficients to equilibrium correlation functions (Eqs. 4 and 5).
Assumed framework of linear response theory.
domain assumption The pressure operator for a dilute Fermi gas with contact interactions is p = 2H/3 + C/(12πma) (Eq. 6).
Uses Tan relations; valid in the zero-range limit.
domain assumption The dissipative part of pressure fluctuations is entirely due to the contact operator (Eq. 9).
Projection of pressure fluctuations onto conserved densities leaves only the contact term.
ad hoc to paper The bulk viscosity spectral function is a single Drude peak with relaxation time τζ (Eq. 12).
Used to obtain exponential relaxation and the attractor; neglects the high-frequency contact tail.
domain assumption Variation of scattering length acts as a local scale expansion with Va = -3 ȧ/a.
Equivalence between expansion and scattering-length ramps from [43].

how reviews work

0 comments

Cite this review

Pith. "Pith review of Quantum transport in strongly correlated Fermi gases." pith.science (2026). https://pith.science/paper/XNSXUBUC

@misc{pith2026241113165,
  author       = {Pith},
  title        = {Pith review of: Quantum transport in strongly correlated Fermi gases},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/XNSXUBUC}},
  note         = {Machine review of arXiv:2411.13165}
}

read the original abstract

Transport in strongly correlated fermions cannot be understood by fermionic quasiparticles alone. We present a theoretical framework for quantum transport that incorporates strong local correlations of fermion pairs. These contact correlations add essential contributions to viscous, thermal and sound transport coefficients. The bulk viscosity, in particular, receives its dominant contribution from pair excitations. Moreover, it can be measured elegantly by observing the response to a time-dependent scattering length even when the fluid is not moving. Rapid changes of the scattering length drive the system far out of local equilibrium, and we show how it relaxes back to equilibrium following a hydrodynamic attractor before a Navier-Stokes description becomes valid.

Figures

Figures reproduced from arXiv: 2411.13165 by the authors.

**Figure 1.** Hydrodynamic attractor. The normalized bulk pressure c(t) − ceq(t) = π(t)/χ exhibits different time evolutions for different initial conditions (thin lines), which quickly converge toward the attractor solution (thick blue line) and only later approach NavierStokes hydrodynamics (green dashed line). Adapted from [20]. hydrodynamics is predicted. This is exemplified by a power-law drive a −1 (t > tini) ≡ a −1 ini(t/… view at source ↗

Discussion (0). Continue with ORCID to comment.

Forward citations

Cited by 1 Pith paper

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score. Full citation record

Few is different: deciphering many-body dynamics in mesoscopic quantum gases
cond-mat.quant-gas 2025-09 unverdicted novelty 3.0 of 10

A workshop report mapping the size, equilibrium, and interaction frontiers of hydrodynamic behavior in mesoscopic quantum systems, connecting few-atom Fermi gases and high-energy small collision systems.

Reference graph

Works this paper leans on

50 extracted references · 49 canonical work pages · cited by 1 Pith paper

[20]

Hydrodynamic Attractor in Ultracold Atoms

K. Fujii, T . Enss, “Hydrodynamic Attractor in Ultracold Atoms”,Phys. Rev. Lett. 133 (2024), no. 17, p. 173402

work page 2024
[35]

Bulk Viscosity and Contact Correlations in Attractive Fermi Gases

T . Enss, “Bulk Viscosity and Contact Correlations in Attractive Fermi Gases”,Phys. Rev. Lett. 123 (2019), p. 205301

work page 2019
[41]

Bulk viscosity of resonantly interacting fermions in the quantum virial expansion

K. Fujii, T . Enss, “Bulk viscosity of resonantly interacting fermions in the quantum virial expansion”,Annals of Physics 453 (2023), p. 169296

work page 2023
[1]

Universal spin transport in a strongly interacting Fermi gas

A. Sommer, M. Ku, G. Roati, M. W . Zwierlein, “Universal spin transport in a strongly interacting Fermi gas”, Nature (London) 472 (2011), p. 201-204

work page 2011
[2]

Nearly perfect fluidity: from cold atomic gases to hot quark gluon plasmas

T . Schäfer, D. Teaney, “Nearly perfect fluidity: from cold atomic gases to hot quark gluon plasmas”, Rep. Prog. Phys. 72 (2009), p. 126001

work page 2009
[3]

Observation of Universal Temperature Scaling in the Quantum Viscosity of a Unitary Fermi Gas

C. Cao, E. Elliott, J. Joseph, H. Wu, J. Petricka, T . Schäfer, J. E. Thomas, “Observation of Universal Temperature Scaling in the Quantum Viscosity of a Unitary Fermi Gas”, Science 331 (2011), p. 58-61

work page 2011
[4]

Viscosity and scale invariance in the unitary Fermi gas

T . Enss, R. Haussmann, W . Zwerger, “Viscosity and scale invariance in the unitary Fermi gas”, Ann. Phys. (N.Y.) 326 (2011), p. 770-796

work page 2011
[5]

Quantum Mechanical Limitations to Spin Transport in the Unitary Fermi Gas

T . Enss, R. Haussmann, “Quantum Mechanical Limitations to Spin Transport in the Unitary Fermi Gas”, Phys. Rev. Lett. 109 (2012), p. 195303

work page 2012

Show all 50 references

[6]

Transverse Demagnetization Dynamics of a Unitary Fermi Gas

A. B. Bardon, S. Beattie, C. Luciuk, W . Cairncross, D. Fine, N. S. Cheng, G. J. A. Edge, E. Taylor, S. Zhang, S. Trotzky, J. H. Thywissen, “Transverse Demagnetization Dynamics of a Unitary Fermi Gas”,Science 344 (2014), p. 722-724

2014
[7]

Observation of the Leggett-Rice Effect in a Unitary Fermi Gas

S. Trotzky, S. Beattie, C. Luciuk, S. Smale, A. B. Bardon, T . Enss, E. Taylor, S. Zhang, J. H. Thywissen, “Observation of the Leggett-Rice Effect in a Unitary Fermi Gas”, Phys. Rev. Lett. 114 (2015), p. 015301

2015
[8]

Observation of quantum- limited spin transport in strongly interacting two-dimensional Fermi gases

C. Luciuk, S. Smale, F . Böttcher, H. Sharum, B. A. Olsen, S. Trotzky, T . Enss, J. H. Thywissen, “Observation of quantum- limited spin transport in strongly interacting two-dimensional Fermi gases”, Phys. Rev. Lett. 118 (2017), p. 130405

2017
[9]

Universal Spin Transport and Quantum Bounds for Unitary Fermions

T . Enss, J. H. Thywissen, “Universal Spin Transport and Quantum Bounds for Unitary Fermions”,Annu. Rev. Condens. Matter Phys. 10 (2019), p. 85-106

2019
[10]

Thermal conductivity and sound attenuation in dilute atomic Fermi gases

M. Braby, J. Chao, T . Schäfer, “Thermal conductivity and sound attenuation in dilute atomic Fermi gases”,Phys. Rev. A 82 (2010), p. 033619

2010
[11]

Universal sound diffusion in a strongly interacting Fermi gas

P . B. Patel, Z. Yan, B. Mukherjee, R. J. Fletcher, J. Struck, M. W . Zwierlein, “Universal sound diffusion in a strongly interacting Fermi gas”, Science 370 (2020), no. 6521, p. 1222-1226

2020
[12]

Sound propagation and quantum-limited damping in a two-dimensional Fermi gas

M. Bohlen, L. Sobirey, N. Luick, H. Biss, T . Enss, T . Lompe, H. Moritz, “Sound propagation and quantum-limited damping in a two-dimensional Fermi gas”, Phys. Rev. Lett. 124 (2020), no. 24, p. 240403

2020
[13]

Quantum critical thermal transport in the unitary Fermi gas

B. Frank, W . Zwerger, T . Enss, “Quantum critical thermal transport in the unitary Fermi gas”,Phys. Rev. Res. 2 (2020), no. 2, p. 023301

2020
[14]

Second sound attenuation near quantum criticality

X. Li, X. Luo, S. Wang, K. Xie, X.-P . Liu, H. Hu, Y.-A. Chen, X.-C. Yao, J.-W . Pan, “Second sound attenuation near quantum criticality”, Science 375 (2022), no. 6580, p. 528-533

2022
[15]

Hydrodynamic relaxation in a strongly interacting Fermi gas

X. Wang, X. Li, I. Arakelyan, J. E. Thomas, “Hydrodynamic relaxation in a strongly interacting Fermi gas”, Phys. Rev. Lett. 128 (2022), no. 9, p. 090402

2022
[16]

Thermography of the superfluid transition in a strongly interacting Fermi gas

Z. Yan, P . B. Patel, B. Mukherjee, C. J. Vale, R. J. Fletcher, M. W . Zwierlein, “Thermography of the superfluid transition in a strongly interacting Fermi gas”, Science 383 (2024), no. 6683, p. 629-633

2024
[17]

Universal density shift coefficients for the thermal conductivity and shear viscosity of a unitary Fermi gas

X. Li, J. Huang, J. E. Thomas, “Universal density shift coefficients for the thermal conductivity and shear viscosity of a unitary Fermi gas”, Phys. Rev. Res. 6 (2024), no. 4, p. L042021

2024
[18]

Renormalization-group fixed points, universal phase diagram, and 1/N expansion for quan- tum liquids with interactions near the unitarity limit

P . Nikoli´ c, S. Sachdev, “Renormalization-group fixed points, universal phase diagram, and 1/N expansion for quan- tum liquids with interactions near the unitarity limit”, Phys. Rev. A 75 (2007), p. 033608

2007
[19]

Quantum critical transport in the unitary Fermi gas

T . Enss, “Quantum critical transport in the unitary Fermi gas”, Phys. Rev. A 86 (2012), p. 013616

2012
[21]

Hydrodynamic attractor in periodically driven ultracold quantum gases

A. Mazeliauskas, T . Enss, “Hydrodynamic attractor in periodically driven ultracold quantum gases”, arXiv:2501.19240, 2025

2025
[22]

Zwerger (ed.), The BCS–BEC Crossover and the Unitary Fermi Gas , Lecture Notes in Physics Vol

W . Zwerger (ed.), The BCS–BEC Crossover and the Unitary Fermi Gas , Lecture Notes in Physics Vol. 836, Springer, Berlin, 2012

2012
[23]

Smith, H

H. Smith, H. H. Jensen, Transport Phenomena, Oxford University Press, Oxford, UK, 1989

1989
[24]

Viscosity and thermal relaxation for a resonantly interacting Fermi gas

G. M. Bruun, H. Smith, “Viscosity and thermal relaxation for a resonantly interacting Fermi gas”, Phys. Rev. A 72 (2005), p. 043605

2005
[25]

Feshbach Resonances and Medium Effects in Ultracold Atomic Gases

G. M. Bruun, “Feshbach Resonances and Medium Effects in Ultracold Atomic Gases”, Few-Body Systems 45 (2009), p. 227-232

2009
[26]

Transport properties in non-Fermi liquid phases of nodal-point semimetals

I. Mandal, H. Freire, “Transport properties in non-Fermi liquid phases of nodal-point semimetals”,J. Phys.: Condens. Matter 36 (2024), p. 443002

2024
[27]

Transport in p-wave-interacting Fermi gases

J. Maki, T . Enss, “Transport in p-wave-interacting Fermi gases”,Phys. Rev. A 107 (2023), p. 023317

2023
[28]

Viscosity of strongly interacting quantum fluids: spectral functions and sum rules

E. Taylor, M. Randeria, “Viscosity of strongly interacting quantum fluids: spectral functions and sum rules”, Phys. Rev. A 81 (2010), p. 053610. 8 Tilman Enss

2010
[29]

Theory of many-particle systems. I

P . C. Martin, J. Schwinger, “Theory of many-particle systems. I”,Phys. Rev. 115 (1959), p. 1342-1373

1959
[30]

Unitary gas in an isotropic harmonic trap: Symmetry properties and applications

F . Werner, Y. Castin, “Unitary gas in an isotropic harmonic trap: Symmetry properties and applications”,Phys. Rev. A 74 (2006), p. 053604

2006
[31]

Vanishing bulk viscosities and conformal invariance of the unitary Fermi gas

D. T . Son, “Vanishing bulk viscosities and conformal invariance of the unitary Fermi gas”, Phys. Rev. Lett. 98 (2007), p. 020604

2007
[32]

Bulk viscosity of resonating fermions revisited: Kubo formula, sum rule, and the dimer and high- temperature limits

K. Fujii, Y. Nishida, “Bulk viscosity of resonating fermions revisited: Kubo formula, sum rule, and the dimer and high- temperature limits”, Phys. Rev. A 102 (2020), p. 023310

2020
[33]

General relations for quantum gases in two and three dimensions. Two-component fermions

F . Werner, Y. Castin, “General relations for quantum gases in two and three dimensions. Two-component fermions”, Phys. Rev. A 86 (2012), p. 013626

2012
[34]

Viscosity spectral functions of resonating fermions in the quantum virial expansion

Y. Nishida, “Viscosity spectral functions of resonating fermions in the quantum virial expansion”, Ann. Phys. (N.Y.) 410 (2019), p. 167949

2019
[36]

High-temperature expansion of the viscosity in interacting quantum gases

J. Hofmann, “High-temperature expansion of the viscosity in interacting quantum gases”, Phys. Rev. A 101 (2020), p. 013620

2020
[37]

Bulk viscosity and conformal symmetry breaking in the dilute Fermi gas near unitarity

K. Dusling, T . Schäfer, “Bulk viscosity and conformal symmetry breaking in the dilute Fermi gas near unitarity”,Phys. Rev. Lett. 111 (2013), p. 120603

2013
[38]

Thermodynamics of the BCS-BEC crossover

R. Haussmann, W . Rantner, S. Cerrito, W . Zwerger, “Thermodynamics of the BCS-BEC crossover”, Phys. Rev. A 75 (2007), p. 023610

2007
[39]

Spin-independent transport parameters for superfluid 3 He-B

D. Einzel, “Spin-independent transport parameters for superfluid 3 He-B”, J. Low Temp. Phys. 54 (1984), p. 427-474

1984
[40]

Pair-breaking collective branch in BCS superconductors and superfluid Fermi gases

H. Kurkjian, S. N. Klimin, J. Tempere, Y. Castin, “Pair-breaking collective branch in BCS superconductors and superfluid Fermi gases”, Phys. Rev. Lett. 122 (2019), no. 9, p. 093403

2019
[42]

Emergence of Sound in a Tunable Fermi Fluid

S. Huang, Y. Ji, T . Repplinger, G. G. T . Assumpção, J. Chen, G. L. Schumacher, F . J. Vivanco, H. Kurkjian, N. Navon, “Emergence of Sound in a Tunable Fermi Fluid”, arXiv:2407.13769, 2024

2024 arXiv
[43]

Hydrodynamics with spacetime-dependent scattering length

K. Fujii, Y. Nishida, “Hydrodynamics with spacetime-dependent scattering length”, Phys. Rev. A 98 (2018), p. 063634

2018
[44]

Hydrodynamics beyond the gradient expansion: resurgence and resummation

M. P . Heller, M. Spali ´ nski, “Hydrodynamics beyond the gradient expansion: resurgence and resummation”,Phys. Rev. Lett. 115 (2015), no. 7, p. 072501

2015
[45]

Spectral functions of the strongly interacting three-dimensional Fermi gas

C. H. Johansen, B. Frank, J. Lang, “Spectral functions of the strongly interacting three-dimensional Fermi gas”, Phys. Rev. A 109 (2024), p. 023324

2024
[46]

Particle and pair spectra for strongly correlated Fermi gases: A real-frequency solver

T . Enss, “Particle and pair spectra for strongly correlated Fermi gases: A real-frequency solver”, Phys. Rev. A 109 (2024), no. 2, p. 023325

2024
[47]

Spectral properties and observables in ultracold Fermi gases

E. Dizer, J. Horak, J. M. Pawlowski, “Spectral properties and observables in ultracold Fermi gases”, Phys. Rev. A 109 (2024), no. 6, p. 063311

2024
[48]

Observation and quantification of pseudogap in unitary Fermi gases

X. Li, S. Wang, X. Luo, Y.-Y. Zhou, K. Xie, H.-C. Shen, Y.-Z. Nie, Q. Chen, H. Hu, Y.-A. Chen, X.-C. Yao, J.-W . Pan, “Observation and quantification of pseudogap in unitary Fermi gases”, Nature 626 (2024), p. 288-293

2024
[49]

Dynamics of strongly interacting Fermi gases with time-dependent interactions: Conse- quence of conformal symmetry

J. Maki, S. Zhang, F . Zhou, “Dynamics of strongly interacting Fermi gases with time-dependent interactions: Conse- quence of conformal symmetry”, Phys. Rev. Lett. 128 (2022), no. 4, p. 040401

2022
[50]

Bonitz, Quantum kinetic theory, Springer, Cham, 2016

M. Bonitz, Quantum kinetic theory, Springer, Cham, 2016

2016

Pith tools

Reviewed August 12, 2026 · model on record in the stance chip above.

[1] [20]

Hydrodynamic Attractor in Ultracold Atoms

K. Fujii, T . Enss, “Hydrodynamic Attractor in Ultracold Atoms”,Phys. Rev. Lett. 133 (2024), no. 17, p. 173402

work page 2024

[2] [35]

Bulk Viscosity and Contact Correlations in Attractive Fermi Gases

T . Enss, “Bulk Viscosity and Contact Correlations in Attractive Fermi Gases”,Phys. Rev. Lett. 123 (2019), p. 205301

work page 2019

[3] [41]

Bulk viscosity of resonantly interacting fermions in the quantum virial expansion

K. Fujii, T . Enss, “Bulk viscosity of resonantly interacting fermions in the quantum virial expansion”,Annals of Physics 453 (2023), p. 169296

work page 2023

[4] [1]

Universal spin transport in a strongly interacting Fermi gas

A. Sommer, M. Ku, G. Roati, M. W . Zwierlein, “Universal spin transport in a strongly interacting Fermi gas”, Nature (London) 472 (2011), p. 201-204

work page 2011

[5] [2]

Nearly perfect fluidity: from cold atomic gases to hot quark gluon plasmas

T . Schäfer, D. Teaney, “Nearly perfect fluidity: from cold atomic gases to hot quark gluon plasmas”, Rep. Prog. Phys. 72 (2009), p. 126001

work page 2009

[6] [3]

Observation of Universal Temperature Scaling in the Quantum Viscosity of a Unitary Fermi Gas

C. Cao, E. Elliott, J. Joseph, H. Wu, J. Petricka, T . Schäfer, J. E. Thomas, “Observation of Universal Temperature Scaling in the Quantum Viscosity of a Unitary Fermi Gas”, Science 331 (2011), p. 58-61

work page 2011

[7] [4]

Viscosity and scale invariance in the unitary Fermi gas

T . Enss, R. Haussmann, W . Zwerger, “Viscosity and scale invariance in the unitary Fermi gas”, Ann. Phys. (N.Y.) 326 (2011), p. 770-796

work page 2011

[8] [5]

Quantum Mechanical Limitations to Spin Transport in the Unitary Fermi Gas

T . Enss, R. Haussmann, “Quantum Mechanical Limitations to Spin Transport in the Unitary Fermi Gas”, Phys. Rev. Lett. 109 (2012), p. 195303

work page 2012