pith. sign in

arxiv: 2407.04073 · v4 · submitted 2024-07-04 · ❄️ cond-mat.str-el · cond-mat.quant-gas

Deconfined quantum critical points in fermionic systems with spin-charge separation

Pith reviewed 2026-05-23 23:09 UTC · model grok-4.3

classification ❄️ cond-mat.str-el cond-mat.quant-gas
keywords deconfined quantum critical pointsspin-charge separationone-dimensional fermionsquantum phase transitionspartially gapped statesstrongly correlated electronsfield theory
0
0 comments X

The pith

Spin-charge separation in one-dimensional fermions enables partially gapped deconfined quantum critical points.

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

The paper aims to show that spin-charge separation, a feature of interacting fermions in one dimension, can produce deconfined quantum critical points that are only partially gapped. This differs from prior examples where such points remain fully gapless. Low-energy field theory analysis of generic 1D fermionic systems first indicates this possibility. The authors then construct a microscopic lattice model and perform numerical calculations of gaps, local order parameters, and correlation functions to confirm the partially gapped character at transitions between ordered phases.

Core claim

Deconfined quantum critical points are transition points between locally ordered phases not captured by the Landau-Ginzburg-Wilson paradigm. In fermionic systems the spin-charge separation peculiar to interacting low-dimensional particles allows such points to appear in a partially gapped form, as first inferred from field theory of generic one-dimensional systems and then verified by deriving a microscopic model whose numerical gaps, order parameters and correlations exhibit the expected partially gapped deconfined behavior.

What carries the argument

Spin-charge separation in one-dimensional interacting fermions, which decouples spin and charge sectors and permits selective gapping while preserving deconfined criticality.

Load-bearing premise

The low-energy field theory of generic one-dimensional fermions accurately describes the phase transitions realized in the specific microscopic model studied.

What would settle it

Numerical data on the microscopic model showing a fully gapped spectrum or fully gapless correlations at the transition between ordered phases, rather than the predicted partial gapping.

Figures

Figures reproduced from arXiv: 2407.04073 by Arianna Montorsi, Luca Barbiero, Maciej Lewenstein, Matteo Rizzi, Niccol\`o Baldelli, Sergi Juli\`a-Farr\'e.

Figure 1
Figure 1. Figure 1: FIG. 1. (a) Cartoon of the phase diagram of the micro [PITH_FULL_IMAGE:figures/full_fig_p002_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: FIG. 2. Study of the critical point between the BOW and the CDW phases appearing in Eq. ( [PITH_FULL_IMAGE:figures/full_fig_p004_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: FIG. 3. Scaling of the order parameters around the BOW [PITH_FULL_IMAGE:figures/full_fig_p006_3.png] view at source ↗
Figure 5
Figure 5. Figure 5: FIG. 5. Study of the critical point between the BOW and the AF phases appearing in Eq. ( [PITH_FULL_IMAGE:figures/full_fig_p007_5.png] view at source ↗
Figure 6
Figure 6. Figure 6: FIG. 6. Scaling of the order parameters around the the AF [PITH_FULL_IMAGE:figures/full_fig_p007_6.png] view at source ↗
Figure 7
Figure 7. Figure 7: FIG. 7. First order phase transition between the AF and the [PITH_FULL_IMAGE:figures/full_fig_p008_7.png] view at source ↗
Figure 8
Figure 8. Figure 8: FIG. 8. Extrapolation of the order parameters (a) [PITH_FULL_IMAGE:figures/full_fig_p011_8.png] view at source ↗
read the original abstract

Deconfined quantum critical points are intriguing transition points not predicted by the Landau-Ginzburg-Wilson symmetry-breaking paradigm which are usually identified by the appearance of a continuous phase transition between locally ordered phases. Here, we reveal the presence of deconfined quantum critical points with unexplored properties. Contrary to previously known examples, we show that the phenomenon of spin-charge separation peculiar to interacting low dimensional fermions can allow for the appearance of partially gapped deconfined quantum critical points. We first infer this point by performing a field theory analysis of generic one-dimensional fermionic systems in the low energy limit. Subsequently, we derive a microscopic model where phase transitions between different locally ordered phases can take place. Here, by performing a numerical analysis we explicitly derive, among others, the gaps, local order parameters and correlation functions behavior, supporting the presence of partially gapped deconfined quantum critical points. Our results thus provide new interesting insights on the widely investigated topic of quantum phase transitions.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 2 minor

Summary. The paper claims that spin-charge separation in interacting one-dimensional fermions enables partially gapped deconfined quantum critical points (DQCPs), identified via a low-energy field theory analysis of generic fermionic systems followed by construction of a microscopic lattice model whose numerical results on gaps, order parameters, and correlation functions are asserted to confirm the partially gapped DQCP character.

Significance. If the central claim holds, the work extends the known landscape of DQCPs by incorporating fermionic spin-charge separation to produce partially gapped transitions between locally ordered phases, offering a new mechanism distinct from prior bosonic or symmetry-breaking examples and potentially relevant to quantum phase transitions in low-dimensional systems.

major comments (2)
  1. [field theory analysis section] The field theory analysis in the low-energy limit (described in the abstract and early sections) predicts partially gapped DQCPs, but the manuscript does not explicitly demonstrate that the deconfined character survives the inclusion of all relevant inter-sector couplings that could arise from the microscopic model; a concrete check against operator relevance would strengthen the mapping.
  2. [numerical analysis] Numerical section: the reported gaps and order parameters support the partially gapped claim, yet without tabulated error estimates or finite-size scaling details for the correlation functions, it remains unclear whether the numerics rule out a weakly first-order transition or a gapped phase with small but finite correlation length.
minor comments (2)
  1. Notation for the spin and charge velocities and Luttinger parameters should be defined consistently between the field theory and the microscopic model sections to avoid ambiguity in the mapping.
  2. Figure captions for the correlation function plots would benefit from explicit mention of the system sizes used and any fitting procedures applied.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the positive assessment and recommendation of minor revision. We address the major comments point by point below and will incorporate the requested clarifications in the revised manuscript.

read point-by-point responses
  1. Referee: [field theory analysis section] The field theory analysis in the low-energy limit (described in the abstract and early sections) predicts partially gapped DQCPs, but the manuscript does not explicitly demonstrate that the deconfined character survives the inclusion of all relevant inter-sector couplings that could arise from the microscopic model; a concrete check against operator relevance would strengthen the mapping.

    Authors: We agree that an explicit check of operator relevance for inter-sector couplings would add rigor to the mapping. Our field theory is formulated in the generic low-energy limit, but in the revision we will add an appendix that computes the scaling dimensions of the relevant inter-sector operators arising from the microscopic model and confirms that none destabilize the deconfined fixed point. revision: yes

  2. Referee: [numerical analysis] Numerical section: the reported gaps and order parameters support the partially gapped claim, yet without tabulated error estimates or finite-size scaling details for the correlation functions, it remains unclear whether the numerics rule out a weakly first-order transition or a gapped phase with small but finite correlation length.

    Authors: We acknowledge that tabulated errors and more detailed finite-size scaling would make the numerical evidence more conclusive. In the revised version we will include error estimates from the DMRG runs, present correlation-function data with explicit finite-size scaling collapses, and discuss the system sizes used to bound the correlation length and exclude a weakly first-order scenario. revision: yes

Circularity Check

0 steps flagged

No significant circularity detected

full rationale

The paper's central derivation begins with an independent low-energy field theory analysis of generic 1D fermionic systems that infers the existence of partially gapped DQCPs via spin-charge separation, then separately constructs a microscopic lattice model, and finally performs numerical analysis of gaps, order parameters, and correlations to support the claim. No load-bearing step reduces by the paper's own equations to a fitted input, self-definition, or self-citation chain; the field theory and numerics are presented as distinct, externally verifiable steps without internal reduction to the target result.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

The central claim rests on the applicability of low-energy field theory to generic 1D fermions and the existence of a microscopic model whose numerics confirm the predicted partially gapped DQCPs; no free parameters or invented entities are mentioned in the abstract.

axioms (1)
  • domain assumption Low energy effective field theory applies to generic one-dimensional fermionic systems
    Invoked to infer the presence of partially gapped DQCPs from spin-charge separation

pith-pipeline@v0.9.0 · 5723 in / 1228 out tokens · 29608 ms · 2026-05-23T23:09:02.525861+00:00 · methodology

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Lean theorems connected to this paper

Citations machine-checked in the Pith Canon. Every link opens the source theorem in the public Lean library.

What do these tags mean?
matches
The paper's claim is directly supported by a theorem in the formal canon.
supports
The theorem supports part of the paper's argument, but the paper may add assumptions or extra steps.
extends
The paper goes beyond the formal theorem; the theorem is a base layer rather than the whole result.
uses
The paper appears to rely on the theorem as machinery.
contradicts
The paper's claim conflicts with a theorem or certificate in the canon.
unclear
Pith found a possible connection, but the passage is too broad, indirect, or ambiguous to say the theorem truly supports the claim.

Reference graph

Works this paper leans on

115 extracted references · 115 canonical work pages · 2 internal anchors

  1. [1]

    and, the more exotic, symmetric mass generation [7] phase transitions. Within this diversity, the Landau–Ginzburg-Wilson symmetry-breaking paradigm [8, 9] rigorously predicts the appearance of discontinuous phase transitions con- necting locally ordered (LO) phases with different sym- metry properties. Nevertheless, pioneering analysis proved [10, 11] tha...

  2. [2]

    (1)(a), for Jz = 0, the Hamilto- nian in Eq.(16) is the known extended Fermi-Hubbard model [76, 81–84]

    BOW-CDW phase transition As shown in Fig. (1)(a), for Jz = 0, the Hamilto- nian in Eq.(16) is the known extended Fermi-Hubbard model [76, 81–84]. For dominating U/t, the system is in MI. The situation changes drastically for larger val- ues of V . Here, two LO phases can take place: a BOW phase when V ∼ U are away from strongly interacting perturbative re...

  3. [3]

    (16) for Jz > 0 which phase diagram is shown in Fig

    AF-BOW phase transition We now move to the analysis of the model in Eq. (16) for Jz > 0 which phase diagram is shown in Fig. (1)(b). As specified, a finite antiferromagnetic coupling allows for the breaking of the discrete spin flip symmetry. A part from slightly moving the transition points, we find indeed that the main role played by small Jz is to re- ...

  4. [4]

    The size L refers to a finite MPS constructed out of L/2 unit cells

    (a) Values of the order parameters OBOW and OAF for different dimension χ; (a) Values of the Luttinger parameter Kc and Ks at fixed bond dimension. The size L refers to a finite MPS constructed out of L/2 unit cells. a SU (2) symmetry related to the spin degrees of free- dom not present in either the BOW or the AF phase. Fig. 5(c) also demonstrates that s...

  5. [5]

    As already pointed out at the level of field theory, in or- der to find such transition to be continuous, both gaps have to vanish at the transition point

    AF-CDW phase transition Finally, we study the AF-CDW phase transition. As already pointed out at the level of field theory, in or- der to find such transition to be continuous, both gaps have to vanish at the transition point. This aspect clearly rules out the possible presence of a partly gapped DQCPs while, in principle, it still allows for standard ful...

  6. [6]

    hysteresis type phenomenon

    and noise correlators measurements [98] allow for an accurate detection of local density [99] and spin [100] orderings and therefore for an accurate probing of non- local order parameters and locally ordered phases. As consequence, we believe that our results not only unveil a novel interesting type of deconfined quantum critical points but also pave the ...

  7. [7]

    (A3), the competition between the quadratic and the cosine terms determines the properties of the sys- tem

    Derivation of gapped phases and symmetry breaking In Eq. (A3), the competition between the quadratic and the cosine terms determines the properties of the sys- tem. Specifically, in the first line fluctuations of the fields are promoted, whereas the cosine term in the second line favors the pinning of the field φν(x) to a x independent value minimizing th...

  8. [8]

    (A9) Based on the previous results, it is thus possible to pre- dict that the transitions between LO phases occur inde- pendently in the two channels for gν = 0

    Bosonization of the microscopic model The bosonization technique of the microscopic model H = − t X j,σ (c† j,σcj+1,σ + h.c.) + U X j nj,↑nj,↓ + X j (V S c j Sc j+1 + JzSs j Ss j+1) (A8) provides the following quantities vν = 2at(2 − Kν), Kc = 1 − 1 4πt U + 6V + 2Jz , Ks = 1 − 1 4πt −U + 2V + 6Jz , gc = − U − 2V + 2Jz a = −gs. (A9) Based on the previous r...

  9. [9]

    C. Domb, M. S. Green, and J. L. Lebowitz, Phase Tran- sitions and Critical Phenomena , Phase Transitions and Critical Phenomena No. v. 8 (Academic Press, 1972)

  10. [10]

    Sachdev, Quantum Phase Transitions, 2nd ed

    S. Sachdev, Quantum Phase Transitions, 2nd ed. (Cam- bridge University Press, 2011)

  11. [11]

    Binder, Reports on Progress in Physics 50, 783 (1987)

    K. Binder, Reports on Progress in Physics 50, 783 (1987)

  12. [12]

    V. L. Berezinsky, Sov. Phys. JETP 32, 493 (1971)

  13. [13]

    J. M. Kosterlitz and D. J. Thouless, Journal of Physics C: Solid State Physics 6, 1181 (1973)

  14. [14]

    L. D. Landau, Zh. Eksp. Teor. Fiz. 7, 19 (1937)

  15. [15]

    Wang and Y.-Z

    J. Wang and Y.-Z. You, Symmetry 14 (2022), 10.3390/sym14071475

  16. [16]

    L. D. Landau, E. M. Lifshitz, and M. Pitaevskii, Sta- tistical Physics (Butterworth-Heinemann, New York, 1999)

  17. [17]

    K. G. Wilson and J. Kogut, Phys. Rep. 12, 75 (1974)

  18. [18]

    Senthil, A

    T. Senthil, A. Vishwanath, L. Balents, S. Sachdev, and M. P. A. Fisher, Science 303, 1490 (2004)

  19. [19]

    Senthil, L

    T. Senthil, L. Balents, S. Sachdev, A. Vishwanath, and M. P. A. Fisher, Phys. Rev. B 70, 144407 (2004)

  20. [20]

    Senthil, (2023), arXiv:2306.12638 [cond-mat.str-el]

    T. Senthil, (2023), arXiv:2306.12638 [cond-mat.str-el]

  21. [21]

    A. W. Sandvik, Phys. Rev. Lett. 98, 227202 (2007)

  22. [22]

    Jiang, M

    F.-J. Jiang, M. Nyfeler, S. Chandrasekharan, and U.- J. Wiese, J. Stat. Mech.: Theory Exp 2008, P02009 (2008)

  23. [23]

    J. Lou, A. W. Sandvik, and N. Kawashima, Phys. Rev. B 80, 180414 (2009)

  24. [24]

    Banerjee, K

    A. Banerjee, K. Damle, and F. Alet, Phys. Rev. B 82, 155139 (2010)

  25. [25]

    A. W. Sandvik, Phys. Rev. Lett. 104, 177201 (2010)

  26. [26]

    Harada, T

    K. Harada, T. Suzuki, T. Okubo, H. Matsuo, J. Lou, H. Watanabe, S. Todo, and N. Kawashima, Phys. Rev. B 88, 220408 (2013)

  27. [27]

    K. Chen, Y. Huang, Y. Deng, A. B. Kuklov, N. V. Prokof’ev, and B. V. Svistunov, Phys. Rev. Lett. 110, 185701 (2013)

  28. [28]

    Nahum, J

    A. Nahum, J. T. Chalker, P. Serna, M. Ortu˜ no, and A. M. Somoza, Phys. Rev. X 5, 041048 (2015)

  29. [29]

    H. Shao, W. Guo, and A. W. Sandvik, Science 352, 213 (2016)

  30. [30]

    C. Wang, A. Nahum, M. A. Metlitski, C. Xu, and T. Senthil, Phys. Rev. X 7, 031051 (2017)

  31. [31]

    J. Y. Lee, Y.-Z. You, S. Sachdev, and A. Vishwanath, Phys. Rev. X 9, 041037 (2019)

  32. [32]

    Y.-C. Wang, N. Ma, M. Cheng, and Z. Y. Meng, SciPost Phys. 13, 123 (2022)

  33. [33]

    M. Song, J. Zhao, L. Janssen, M. M. Scherer, and Z. Y. Meng, (2023), arXiv:2307.02547 [cond-mat.str-el]

  34. [34]

    Deconfined quantum criticality and emergent SO(5) symmetry in fermionic systems

    Z.-X. Li, S.-K. Jian, and H. Yao, (2019), arXiv:1904.10975 [cond-mat.str-el]

  35. [35]

    F. F. Assaad and T. Grover, Phys. Rev. X 6, 041049 (2016)

  36. [36]

    Z. H. Liu, W. Jiang, B.-B. Chen, J. Rong, M. Cheng, K. Sun, Z. Y. Meng, and F. F. Assaad, Phys. Rev. Lett. 130, 266501 (2023)

  37. [37]

    Y. D. Liao, G. Pan, W. Jiang, Y. Qi, and Z. Y. Meng, (2023), arXiv:2302.11742 [cond-mat.str-el]

  38. [38]

    Charrier, F

    D. Charrier, F. Alet, and P. Pujol, Phys. Rev. Lett. 101, 167205 (2008)

  39. [39]

    G. J. Sreejith and S. Powell, Phys. Rev. B 92, 184413 (2015)

  40. [40]

    Jiang and O

    S. Jiang and O. Motrunich, Phys. Rev. B 99, 075103 (2019)

  41. [41]

    Roberts, S

    B. Roberts, S. Jiang, and O. I. Motrunich, Phys. Rev. B 99, 165143 (2019)

  42. [42]

    Huang, D.-C

    R.-Z. Huang, D.-C. Lu, Y.-Z. You, Z. Y. Meng, and T. Xiang, Phys. Rev. B 100, 125137 (2019)

  43. [43]

    Mudry, A

    C. Mudry, A. Furusaki, T. Morimoto, and T. Hikihara, Phys. Rev. B 99, 205153 (2019)

  44. [44]

    Roberts, S

    B. Roberts, S. Jiang, and O. I. Motrunich, Phys. Rev. B 103, 155143 (2021)

  45. [45]

    J. Y. Lee, J. Ramette, M. A. Metlitski, V. Vuleti´ c, W. W. Ho, and S. Choi, Phys. Rev. Lett. 131, 083601 (2023)

  46. [46]

    Baldelli, C

    N. Baldelli, C. R. Cabrera, S. Juli` a-Farr´ e, M. Aidels- burger, and L. Barbiero, Phys. Rev. Lett. 132, 153401 (2024)

  47. [47]

    Romen, S

    A. Romen, S. Birnkammer, and M. Knap, SciPost Phys. Core 7, 008 (2024)

  48. [48]

    Tomonaga, Progress of Theoretical Physics 5, 544 (1950)

    S. Tomonaga, Progress of Theoretical Physics 5, 544 (1950)

  49. [49]

    J. M. Luttinger, Journal of Mathematical Physics 4, 1154 (1963)

  50. [50]

    F. D. M. Haldane, Journal of Physics C Solid State Physics 14, 2585 (1981). 13

  51. [51]

    A. M. T. Alexander O. Gogolin, Alexander A. Ners- esyan, Bosonization and Strongly Correlated Systems (Cambridge University Press, 1998)

  52. [52]

    Giamarchi, Quantum Physics in One Dimension (Oxford University Press, 2004)

    T. Giamarchi, Quantum Physics in One Dimension (Oxford University Press, 2004)

  53. [53]

    Haegeman, T

    J. Haegeman, T. J. Osborne, and F. Verstraete, Phys. Rev. B 88, 075133 (2013)

  54. [54]

    Zauner-Stauber, L

    V. Zauner-Stauber, L. Vanderstraeten, M. T. Fishman, F. Verstraete, and J. Haegeman, Phys. Rev. B 97, 045145 (2018)

  55. [55]

    Tagliacozzo, T

    L. Tagliacozzo, T. R. de Oliveira, S. Iblisdir, and J. I. Latorre, Phys. Rev. B 78, 024410 (2008)

  56. [56]

    M. M. Rams, P. Czarnik, and L. Cincio, Phys. Rev. X 8, 041033 (2018)

  57. [57]

    Vanhecke, J

    B. Vanhecke, J. Haegeman, K. Van Acoleyen, L. Van- derstraeten, and F. Verstraete, Phys. Rev. Lett. 123, 250604 (2019)

  58. [59]

    Montorsi and M

    A. Montorsi and M. Roncaglia, Phys. Rev. Lett. 109, 236404 (2012)

  59. [60]

    Barbiero, A

    L. Barbiero, A. Montorsi, and M. Roncaglia, Phys. Rev. B 88, 035109 (2013)

  60. [61]

    Montorsi, F

    A. Montorsi, F. Dolcini, R. C. Iotti, and F. Rossi, Phys. Rev. B 95, 245108 (2017)

  61. [62]

    Pollmann, E

    F. Pollmann, E. Berg, A. M. Turner, and M. Oshikawa, Phys. Rev. B 85, 075125 (2012)

  62. [63]

    Tang and X.-G

    E. Tang and X.-G. Wen, Phys. Rev. Lett. 109, 096403 (2012)

  63. [64]

    Wen, Phys

    X.-G. Wen, Phys. Rev. B 89, 035147 (2014)

  64. [65]

    Gu and X.-G

    Z.-C. Gu and X.-G. Wen, Phys. Rev. B 90, 115141 (2014)

  65. [66]

    Senthil, Annual Review of Condensed Matter Physics 6, 299 (2015)

    T. Senthil, Annual Review of Condensed Matter Physics 6, 299 (2015)

  66. [67]

    Shapourian, K

    H. Shapourian, K. Shiozaki, and S. Ryu, Phys. Rev. Lett. 118, 216402 (2017)

  67. [68]

    F. D. M. Haldane, Phys. Rev. Lett. 50, 1153 (1983)

  68. [69]

    Affleck, T

    I. Affleck, T. Kennedy, E. H. Lieb, and H. Tasaki, Phys. Rev. Lett. 59, 799 (1987)

  69. [70]

    Barbiero, L

    L. Barbiero, L. Dell’Anna, A. Trombettoni, and V. E. Korepin, Phys. Rev. B 96, 180404 (2017)

  70. [71]

    E. G. Dalla Torre, E. Berg, and E. Altman, Phys. Rev. Lett. 97, 260401 (2006)

  71. [72]

    Rossini and R

    D. Rossini and R. Fazio, New Journal of Physics 14, 065012 (2012)

  72. [73]

    Sugimoto, S

    K. Sugimoto, S. Ejima, F. Lange, and H. Fehske, Phys. Rev. A 99, 012122 (2019)

  73. [74]

    Fraxanet, D

    J. Fraxanet, D. Gonz´ alez-Cuadra, T. Pfau, M. Lewen- stein, T. Langen, and L. Barbiero, Phys. Rev. Lett. 128, 043402 (2022)

  74. [75]

    Fazzini, L

    S. Fazzini, L. Barbiero, and A. Montorsi, Phys. Rev. Lett. 122, 106402 (2019)

  75. [76]

    Montorsi, S

    A. Montorsi, S. Fazzini, and L. Barbiero, Phys. Rev. A 101, 043618 (2020)

  76. [77]

    Anfuso and A

    F. Anfuso and A. Rosch, Phys. Rev. B 75, 144420 (2007)

  77. [78]

    S. R. Manmana, A. M. Essin, R. M. Noack, and V. Gu- rarie, Phys. Rev. B 86, 205119 (2012)

  78. [79]

    Barbiero, L

    L. Barbiero, L. Santos, and N. Goldman, Phys. Rev. B 97, 201115 (2018)

  79. [80]

    Juli` a-Farr´ e, D

    S. Juli` a-Farr´ e, D. Gonz´ alez-Cuadra, A. Patscheider, M. J. Mark, F. Ferlaino, M. Lewenstein, L. Barbiero, and A. Dauphin, Phys. Rev. Res. 4, L032005 (2022)

  80. [81]

    L. P. Kadanoff and H. Ceva, Phys. Rev. B 3, 3918 (1971)

Showing first 80 references.