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arxiv: 2605.21838 · v1 · pith:WK7A3Y42new · submitted 2026-05-21 · ✦ hep-th · gr-qc

New mechanism for fermion localization in f(T,T_G)-brane

Pith reviewed 2026-05-22 05:51 UTC · model grok-4.3

classification ✦ hep-th gr-qc
keywords fermion localizationbraneworldteleparallel gravityGauss-Bonnet termzero modeKaluza-Klein modesShannon entropy
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0 comments X

The pith

The teleparallel Gauss-Bonnet term modifies fermion localization so that only one chiral zero mode binds to the brane.

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

In five-dimensional braneworld models built from modified teleparallel gravity with a general f(T, T_G) function, the localization of Dirac fermions is examined through a non-minimal coupling to the torsional invariants. This coupling produces Schrödinger-like equations for the Kaluza-Klein modes whose effective potentials are reshaped by the teleparallel Gauss-Bonnet contribution. The resulting potentials allow only one chiral component of the zero mode to localize on the brane, while the degree of confinement varies with the choice of f. Massive modes form a continuous spectrum that can support resonant states, and information measures such as Shannon entropy indicate that the torsional terms redistribute probability to favor tighter localization.

Core claim

In the f(T, T_G)-brane scenario the non-minimal coupling of the Dirac spinor to the torsional invariants T and T_G generates effective potentials in which the zero mode of only one chirality is normalizable and bound to the brane; the teleparallel Gauss-Bonnet term alters the shape of these potentials, the massive spectrum remains continuous yet exhibits resonances, and Shannon entropy together with relative probability quantify a stronger confinement induced by the higher-order torsional terms.

What carries the argument

The effective potential in the Schrödinger-like equation obtained after non-minimal coupling of the Dirac field to the torsion scalar T and the teleparallel Gauss-Bonnet invariant T_G.

If this is right

  • Only one chiral component of the fermion zero mode localizes on the brane, with the degree of confinement set by the specific f(T, T_G) model.
  • The massive Kaluza-Klein spectrum is continuous but develops resonant states from the internal structure of the modified potentials.
  • Shannon entropy and relative probability show that the torsional terms induce a redistribution of information that strengthens localization.
  • Higher-order torsional contributions produce stronger confinement than models that omit the Gauss-Bonnet term.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The same torsional mechanism could be applied in other modified-gravity braneworlds to achieve chiral-selective localization without additional fine-tuning.
  • Resonant massive modes might leave detectable signatures in collider searches for extra dimensions.
  • Information-theoretic diagnostics could be used to compare localization strength across standard warped and teleparallel braneworld constructions.

Load-bearing premise

The non-minimal coupling between the Dirac spinor and the torsional invariants T and T_G is assumed to be valid and to produce consistent Schrödinger-like equations in the five-dimensional geometry.

What would settle it

An explicit solution of the zero-mode equation for any chosen f(T, T_G) that yields normalizable bound states for both left- and right-handed chiral components would disprove the claim that only one chirality localizes.

Figures

Figures reproduced from arXiv: 2605.21838 by Allan R. P. Moreira, Fernando M. Belchior, Guo-Hua Sun, Shi-Hai Dong.

Figure 1
Figure 1. Figure 1: The effective potential for λ = p = ξ = 1, and various values of the modified gravity parameter α [PITH_FULL_IMAGE:figures/full_fig_p008_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: The Zero-mode for λ = p = ξ = 1, and various values of the modified gravity parameter α. 1. Zero-mode localization The massless sector (m = 0) admits analytical solutions of the form φL0,R0(z) ∝ exp  ± ˆ U(z) dz . (30) Normalizability requires ˆ ∞ −∞ |φ(z)| 2 dz < ∞. (31) Using the asymptotic behavior e A(z) ∼ 1/|z| for large |z|, one finds that only one chiral compo￾nent (left-handed for ξ > 0) can be l… view at source ↗
Figure 3
Figure 3. Figure 3: The massive modes for λ = p = ξ = 1, for the f1 case of (28) and various values of the modified gravity parameter α. associated with f2(T, TG), also displays a localized zero-mode centered at the brane, but with a more pronounced sensitivity to negative values of α. In this case, the peak becomes sharper and narrower as |α| increases, suggesting a higher degree of confinement. In both scenarios, the normal… view at source ↗
Figure 4
Figure 4. Figure 4: The massive modes for λ = p = ξ = 1, for the f2 case of (29) and various values of the modified gravity parameter α. increases, the amplitude of the oscillations becomes more pronounced, indicating a stronger inter￾action between the fermionic modes and the modified gravitational background. The distinction between even and odd parity is reflected in the boundary conditions at the origin, with even modes a… view at source ↗
Figure 5
Figure 5. Figure 5: The entropic densities for λ = p = ξ = 1. domains contributing to the entropy of the system. B. Resonant structure and relative probability We now turn to the analysis of the massive fermionic spectrum. Although these modes are not strictly localized, certain states may exhibit enhanced amplitudes near the brane, behaving as resonances. Such resonant modes arise when the effective potential forms a quasi-b… view at source ↗
Figure 6
Figure 6. Figure 6: The relative probability for ξ = p = λ = 1 and α = 0.1 [PITH_FULL_IMAGE:figures/full_fig_p015_6.png] view at source ↗
read the original abstract

We investigate the localization of fermionic fields in a five-dimensional braneworld scenario within the framework of modified teleparallel gravity described by a general $f(T,T_G)$ function. Considering a non-minimal coupling between a Dirac spinor and the torsional invariants, we derive the effective Schr\"odinger-like equations governing the Kaluza-Klein modes. We showed that the contribution of the teleparallel Gauss-Bonnet term significantly modifies the effective potentials and, consequently, the localization properties. The zero-mode analysis reveals that only one chiral component can be localized on the brane, with the degree of confinement depending on the chosen model. In the massive sector, the spectrum is continuous, but resonant states arise due to the internal structure of the potentials. Additionally, we employ information-theoretic measures, such as Shannon entropy and relative probability, to quantify the localization mechanism. Our results show that the torsional modifications induce a nontrivial redistribution of information, exhibiting stronger localization. These findings highlight the role of higher-order torsional terms in shaping fermionic localization and resonance structures in braneworld scenarios.

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

3 major / 2 minor

Summary. The manuscript investigates fermion localization in a five-dimensional braneworld within f(T, T_G) modified teleparallel gravity. A non-minimal coupling between the Dirac spinor and torsional invariants is introduced to derive effective Schrödinger-like equations for Kaluza-Klein modes. The teleparallel Gauss-Bonnet term is shown to modify the effective potentials, allowing localization of only one chiral zero mode on the brane while the massive spectrum remains continuous with resonant states; Shannon entropy and relative probability are employed to quantify the localization.

Significance. If the central derivation holds, the work identifies a potential role for higher-order torsional invariants in shaping fermion localization and resonance structures beyond standard braneworld models, with information-theoretic measures providing a quantitative characterization of confinement strength. The approach could inform model-building in modified gravity scenarios, though its generality is limited by model-specific choices.

major comments (3)
  1. [Section on effective potential derivation] The derivation of the effective Schrödinger-like equation (presumably in the section following the 5D Dirac action) assumes the chosen warp factor and f(T, T_G) satisfy the modified teleparallel field equations in the presence of the non-minimal fermion coupling; no explicit solution or consistency check of these equations is provided to rule out additional constraints that would alter the potentials.
  2. [Zero-mode analysis] The zero-mode analysis claims localization of only one chiral component with normalization independent of coupling strength, yet no explicit evaluation of the normalization integral across different values of the non-minimal coupling parameter is shown, leaving open whether the result is robust or parameter-tuned.
  3. [Massive sector and resonances] Resonant states in the massive sector are identified from the internal structure of the potentials, but no quantitative error estimates, widths, or stability analysis are supplied, weakening the claim that these resonances are physically relevant.
minor comments (2)
  1. [Abstract] The abstract does not provide the explicit functional form of f(T, T_G) employed in the concrete examples, which would help readers assess the generality of the reported modifications.
  2. [Introduction and setup] Notation for the torsional invariants and the non-minimal coupling term could be clarified with a dedicated table or explicit definitions early in the text to improve readability.

Simulated Author's Rebuttal

3 responses · 0 unresolved

We thank the referee for the careful reading and constructive comments on our manuscript. We address each major comment point by point below, indicating the revisions planned for the updated version.

read point-by-point responses
  1. Referee: [Section on effective potential derivation] The derivation of the effective Schrödinger-like equation (presumably in the section following the 5D Dirac action) assumes the chosen warp factor and f(T, T_G) satisfy the modified teleparallel field equations in the presence of the non-minimal fermion coupling; no explicit solution or consistency check of these equations is provided to rule out additional constraints that would alter the potentials.

    Authors: We agree that an explicit consistency check would strengthen the presentation. In the revised manuscript we will add a brief verification showing that the chosen warp factor and f(T, T_G) satisfy the background teleparallel field equations in the absence of the fermion. The non-minimal coupling is introduced in the probe approximation on this fixed background, which is the standard procedure in braneworld localization analyses; consequently the effective potentials remain unaltered by additional constraints from the coupling. revision: yes

  2. Referee: [Zero-mode analysis] The zero-mode analysis claims localization of only one chiral component with normalization independent of coupling strength, yet no explicit evaluation of the normalization integral across different values of the non-minimal coupling parameter is shown, leaving open whether the result is robust or parameter-tuned.

    Authors: The normalization integral for the zero mode converges due to the asymptotic behavior of the warp factor and is formally independent of the coupling parameter once the localization condition is satisfied. To make this explicit, the revised manuscript will include numerical evaluations of the normalization constant for several representative values of the non-minimal coupling, confirming that the result holds across the parameter range of interest. revision: yes

  3. Referee: [Massive sector and resonances] Resonant states in the massive sector are identified from the internal structure of the potentials, but no quantitative error estimates, widths, or stability analysis are supplied, weakening the claim that these resonances are physically relevant.

    Authors: We accept that quantitative support would improve the discussion of physical relevance. In the revision we will supply approximate resonance widths obtained via the WKB approximation together with a short stability analysis based on the absence of tachyonic modes and the shape of the effective potentials. revision: yes

Circularity Check

0 steps flagged

Derivation of effective potentials and localization from non-minimal coupling is self-contained

full rationale

The paper starts from the 5D Dirac action with non-minimal coupling to T and T_G, assumes a standard warped metric, reduces the Dirac equation to a Schrödinger-like form, and analyzes zero-mode localization and resonances for explicit choices of f(T,T_G). These steps follow standard dimensional reduction without any quoted reduction of the central claims to fitted parameters by construction, self-citation chains, or imported uniqueness theorems. The background is solved independently of the test fermion, and the T_G modifications appear explicitly in the derived potentials rather than being smuggled or renamed. The analysis remains parameter-dependent by model choice but does not exhibit circularity in the derivation chain itself.

Axiom & Free-Parameter Ledger

1 free parameters · 2 axioms · 0 invented entities

The central claim depends on a chosen f(T,T_G) function and a non-minimal coupling strength that are introduced to generate the desired potentials rather than derived from a more fundamental principle.

free parameters (1)
  • non-minimal coupling strength
    Parameter that sets the interaction between the Dirac field and torsional invariants; its value controls the depth and shape of the effective potential.
axioms (2)
  • domain assumption The five-dimensional spacetime admits a warped geometry with a thick brane
    Standard assumption in braneworld localization studies invoked to reduce the 5D Dirac equation to an effective 1D Schrödinger problem.
  • standard math The effective potential is obtained by substituting the non-minimal coupling into the Dirac equation and separating variables
    Follows from the usual Kaluza-Klein reduction procedure in the presence of torsion.

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Works this paper leans on

73 extracted references · 73 canonical work pages

  1. [1]

    and in its generalized counterpartf(T, B) [63]. Despite its widespread use, the standard Yukawa coupling may not fully capture how modifications in the underlying gravitational sector affect the localization mechanism of fermions on the brane. This limitation suggests the need for alternative approaches, such as the introduction of more general non-minima...

  2. [2]

    The convergence condition leads to the constraint ξ > λ 2c ,(32) wherec=f(T, T G)||z|→∞

    Zero-mode localization The massless sector (m= 0) admits analytical solutions of the form φL0,R0(z)∝exp ± ˆ U(z)dz .(30) Normalizability requires ˆ ∞ −∞ |φ(z)|2dz <∞.(31) Using the asymptotic behaviore A(z) ∼1/|z|for large|z|, one finds that only one chiral compo- nent (left-handed forξ >0) can be localized. The convergence condition leads to the constrai...

  3. [3]

    Massive spectrum Form̸= 0, the equations must be solved numerically. Due to the parity properties of the potentials, the solutions split into even and odd modes satisfying [65–67] φ′ even(0) = 0, φ even(0)̸= 0,(33) φodd(0) = 0, φ ′ odd(0)̸= 0.(34) The massive modes are not normalizable and correspond to continuum states. Their profiles resemble oscillator...

  4. [4]

    Kaluza, Sitzungsber

    T. Kaluza, Sitzungsber. Preuss. Akad. Wiss. Berlin (Math. Phys. )1921, 966-972 (1921)

  5. [5]

    Klein, Nature118, 516 (1926)

    O. Klein, Nature118, 516 (1926)

  6. [6]

    Arkani-Hamed, S

    N. Arkani-Hamed, S. Dimopoulos and G. R. Dvali, Phys. Lett. B429, 263-272 (1998)

  7. [7]

    Randall and R

    L. Randall and R. Sundrum, Phys. Rev. Lett.83, 4690 (1999)

  8. [8]

    Randall and R

    L. Randall and R. Sundrum, Phys. Rev. Lett.83, 3370 (1999)

  9. [9]

    S. H. Dong, Wave equations in higher dimensions, Springer, Dordrecht, Heidelberg, London, New York, 2011

  10. [10]

    Gregory, V

    R. Gregory, V. A. Rubakov and S. M. Sibiryakov, Phys. Rev. Lett.84, 5928-5931 (2000)

  11. [11]

    Appelquist, H

    T. Appelquist, H. C. Cheng and B. A. Dobrescu, Phys. Rev. D64, 035002 (2001)

  12. [12]

    G. R. Dvali, G. Gabadadze and M. Porrati, Phys. Lett. B485, 208-214 (2000)

  13. [13]

    DeWolfe, D

    O. DeWolfe, D. Z. Freedman, S. S. Gubser and A. Karch, Phys. Rev. D62, 046008 (2000)

  14. [14]

    Gremm, Phys

    M. Gremm, Phys. Lett. B478, 434 (2000)

  15. [15]

    Csaki, J

    C. Csaki, J. Erlich, T. J. Hollowood and Y. Shirman, Nucl. Phys. B581, 309-338 (2000)

  16. [16]

    Gremm, Phys

    M. Gremm, Phys. Rev. D62, 044017 (2000)

  17. [17]

    Dzhunushaliev, V

    V. Dzhunushaliev, V. Folomeev and M. Minamitsuji, Rept. Prog. Phys.73, 066901 (2010)

  18. [18]

    Dzhunushaliev and V

    V. Dzhunushaliev and V. Folomeev, Gen. Rel. Grav.43, 1253-1261 (2011). 16

  19. [19]

    Herrera-Aguilar, D

    A. Herrera-Aguilar, D. Malagon-Morejon, R. R. Mora-Luna and U. Nucamendi, gap, ” Mod. Phys. Lett. A25, 2089-2097 (2010)

  20. [20]

    Dzhunushaliev, V

    V. Dzhunushaliev, V. Folomeev, D. Singleton and S. Aguilar-Rudametkin, Phys. Rev. D77, 044006 (2008)

  21. [21]

    W. D. Goldberger and M. B. Wise, Phys. Rev. Lett.83(1999), 4922

  22. [22]

    Bazeia, A

    D. Bazeia, A. R. Gomes, L. Losano and R. Menezes, Phys. Lett. B671(2009), 402

  23. [23]

    W. J. Geng and H. Lu, Phys. Rev. D93, no.4, 044035 (2016)

  24. [24]

    Dzhunushaliev and V

    V. Dzhunushaliev and V. Folomeev, Gen. Rel. Grav.44, 253-261 (2012)

  25. [25]

    H. L. Jia, W. D. Guo, Y. X. Liu and Q. Tan, JHEP06, 117 (2025)

  26. [26]

    W. Deng, S. Long, Q. Tan, Z. C. Chen and J. Jing, JHEP01, 066 (2026)

  27. [27]

    Bazeia, A

    D. Bazeia, A. S. Lob˜ ao and M. A. Marques, Nucl. Phys. B1007, 116662 (2024)

  28. [28]

    J. L. Rosa, A. S. Lob˜ ao and D. Bazeia, Eur. Phys. J. C82, no.3, 191 (2022)

  29. [29]

    Abdalla, G

    E. Abdalla, G. Franco Abell´ an, A. Aboubrahim, A. Agnello, O. Akarsu, Y. Akrami, G. Alestas, D. Aloni, L. Amendola and L. A. Anchordoqui,et al.JHEAp34, 49-211 (2022)

  30. [30]

    E. N. Saridakiset al.[CANTATA], Spinger (2021), [arXiv:2105.12582 [gr-qc]]

  31. [31]

    Capozziello and M

    S. Capozziello and M. De Laurentis, Phys. Rept.509, 167 (2011)

  32. [32]

    Y. F. Cai, S. Capozziello, M. De Laurentis and E. N. Saridakis, Rept. Prog. Phys.79, 106901 (2016)

  33. [33]

    De Felice and S

    A. De Felice and S. Tsujikawa, Living Rev. Rel.13, 3 (2010)

  34. [34]

    Capozziello, Int

    S. Capozziello, Int. J. Mod. Phys. D11, 483-492 (2002)

  35. [35]

    G. G. L. Nashed and A. Eid, Eur. Phys. J. C86, no.3, 316 (2026)

  36. [36]

    Montani, L

    G. Montani, L. A. Escamilla, N. Carlevaro and E. Di Valentino, Phys. Rev. D113, no.2, 023507 (2026)

  37. [37]

    Valletta, G

    A. Valletta, G. Montani, M. G. Dainotti and E. Fazzari, JHEAp53, 100612 (2026)

  38. [38]

    Kibaro˘ glu, Phys

    S. Kibaro˘ glu, Phys. Dark Univ.47, 101784 (2025)

  39. [39]

    Nojiri and S

    S. Nojiri and S. D. Odintsov, Phys. Lett. B631, 1 (2005)

  40. [40]

    De Felice and S

    A. De Felice and S. Tsujikawa, Phys. Lett. B675, 1-8 (2009)

  41. [41]

    Asimakis, S

    P. Asimakis, S. Basilakos and E. N. Saridakis, Eur. Phys. J. C84, no.2, 207 (2024)

  42. [42]

    Lovelock, J

    D. Lovelock, J. Math. Phys.12, 498 (1971)

  43. [43]

    Deruelle and L

    N. Deruelle and L. Farina-Busto, Phys. Rev. D41, 3696 (1990)

  44. [44]

    G. W. Horndeski, Int. J. Theor. Phys.10, 363-384 (1974)

  45. [45]

    De Felice and S

    A. De Felice and S. Tsujikawa, Phys. Rev. D84, 124029 (2011)

  46. [46]

    Deffayet, X

    C. Deffayet, X. Gao, D. A. Steer and G. Zahariade, Phys. Rev. D84, 064039 (2011)

  47. [47]

    Kobayashi, M

    T. Kobayashi, M. Yamaguchi and J. Yokoyama, Phys. Rev. Lett.105, 231302 (2010)

  48. [48]

    De Felice and S

    A. De Felice and S. Tsujikawa, JCAP02, 007 (2012)

  49. [49]

    W. J. Wolf, P. G. Ferreira and C. Garc´ ıa-Garc´ ıa, Phys. Rev. D113, no.2, 023551 (2026)

  50. [50]

    Garoffolo, K

    A. Garoffolo, K. Hinterbichler and M. Trodden, JHEP09, 115 (2025)

  51. [51]

    Ye and A

    G. Ye and A. Silvestri, Phys. Rev. D111, no.2, 023502 (2025)

  52. [52]

    S. H. Chen, J. B. Dent, S. Dutta and E. N. Saridakis, Phys. Rev. D83, 023508 (2011). 17

  53. [53]

    Bajardi, D

    F. Bajardi, D. Blixt and S. Capozziello, Phys. Rev. D111, no.8, 084012 (2025)

  54. [54]

    C. Wu, X. Ren, Y. Yang, Y. M. Hu and E. N. Saridakis, Eur. Phys. J. C85, no.10, 1099 (2025)

  55. [55]

    Akarsu, B

    O. Akarsu, B. Bulduk, A. De Felice, N. Katırcı and N. M. Uzun, Phys. Rev. D112, no.8, 083532 (2025)

  56. [56]

    Kofinas and E

    G. Kofinas and E. N. Saridakis, Phys. Rev. D90, 084044 (2014)

  57. [57]

    Kofinas and E

    G. Kofinas and E. N. Saridakis, Phys. Rev. D90, 084045 (2014)

  58. [58]

    Bahamonde, C

    S. Bahamonde, C. G. B¨ ohmer and M. Wright, Phys. Rev. D92, no.10, 104042 (2015)

  59. [59]

    Bahamonde and S

    S. Bahamonde and S. Capozziello, Eur. Phys. J. C77, no.2, 107 (2017)

  60. [60]

    C. Q. Geng, C. C. Lee, E. N. Saridakis and Y. P. Wu, Phys. Lett. B704, 384-387 (2011)

  61. [61]

    Bahamonde, K

    S. Bahamonde, K. F. Dialektopoulos and J. Levi Said, Phys. Rev. D100, no.6, 064018 (2019)

  62. [62]

    Bahamonde, K

    S. Bahamonde, K. F. Dialektopoulos, M. Hohmann and J. Levi Said, Class. Quant. Grav.38, no.2, 025006 (2020)

  63. [63]

    Capozziello, M

    S. Capozziello, M. Caruana, J. Levi Said and J. Sultana, JCAP03, 060 (2023)

  64. [64]

    Aldrovandi and J

    R. Aldrovandi and J. G. Pereira,Teleparallel Gravity: An Introduction, (Springer, Berlin, 2013)

  65. [65]

    J. Yang, Y. -L. Li, Y. Zhong and Y. Li, Phys. Rev. D85, 084033 (2012)

  66. [66]

    A. R. P. Moreira, J. E. G. Silva and C. A. S. Almeida, Eur. Phys. J. C81, no.4, 298 (2021)

  67. [67]

    Kofinas and E

    G. Kofinas and E. N. Saridakis, Phys. Rev. D90(2014), 084044

  68. [68]

    C. A. S. Almeida, M. M. Ferreira, Jr., A. R. Gomes and R. Casana, Phys. Rev. D79, 125022 (2009)

  69. [69]

    Y. X. Liu, J. Yang, Z. H. Zhao, C. E. Fu and Y. S. Duan, Phys. Rev. D80, 065019 (2009)

  70. [70]

    Y. X. Liu, H. T. Li, Z. H. Zhao, J. X. Li and J. R. Ren, JHEP10, 091 (2009)

  71. [71]

    C. E. Shannon, Bell Syst. Tech. J.27, no.3, 379-423 (1948)

  72. [72]

    Beckner, Ann

    W. Beckner, Ann. Math.102, 159 (1975)

  73. [73]

    Bia lynicki-Birula and J

    I. Bia lynicki-Birula and J. Mycielski, Commun. Math. Phys.44, no.2, 129-132 (1975). 18