{"id":"ab6422ee-24dd-4166-a9d2-66569be28a11","arxiv_id":"2610.37331","paper_version":1,"verdict":"ACCEPT","confidence":"HIGH","novelty_score":5.0,"correctness_risk":"low","formal_verification":"none","parameter_count":2,"one_line_summary":"For T-duality regularized black holes, tidal forces remain finite at the core, and both the zero-point length and electric charge weaken the accumulated radial stretching.","lead":"This paper calculates how particles orbit and how stretching and squeezing forces act inside a proposed black hole geometry that replaces the central singularity with a small regular core inspired by string theory. It finds that the forces stay finite at the center and that the quantum scale and electric charge both suppress accumulated radial stretching during infall.","discovery_kind":"new_application","skeptic_critique":{"model":"deepseek/deepseek-v4-flash","headline":"Charged metric as written fails its own Reissner-Nordström limit: Eq. (19) gives F → 5/8 at infinity, so Eq. (18)'s charge term is (5/8)Q²/r², contradicting Eq. (20).","rationale":"The reader's weakest_assumption correctly points to the charged metric in Eqs. (18)-(19) as the load-bearing premise for all charged results. My stress test sharpens this into a concrete internal inconsistency: the F(r) printed in Eq. (19) does not have the asymptotic or central behavior required by the paper's own RN limit, Eq. (20), and central expansion, Eq. (21). This is not a disagreement with the published source per se; it is a check of the manuscript's own equations, which fail a direct expansion. If the charged metric is repaired, the qualitative claims about charge suppressing radial stretching may survive, but the quantitative ISCO radii, tidal zeros, and deviation amplitudes would need to be recomputed. The neutral T-duality results, including the finite tidal components, the simultaneous-compression region, and the ℓ0-dependence, are internally consistent and provide independent support for part of the paper's thesis. However, because the charged sector is a major component of the abstract and conclusions, and because the central claim explicitly includes the electric-charge dependence, the inconsistency cannot be ignored at acceptance. A conditional decision requiring verification and correction of Eq. (19) is the appropriate outcome.","tokens_in":33694,"tokens_out":22583,"duration_ms":162983,"concrete_test":"Expand Eq. (19) analytically (or with computer algebra) for r ≫ ℓ0 and in the limit ℓ0 → 0 at fixed r, then substitute into Eq. (18) and compare with Eqs. (20) and (26). If the leading charge term is not exactly Q²/r², repair F(r), or its prefactor in Eq. (18), so that both the ℓ0 → 0 Reissner-Nordström limit and the F(0) implied by Eq. (21) hold; then rerun the charged ISCO, tidal, and deviation-vector calculations behind Figs. 13, 15, 19, 23, and 25. If the corrected F changes the sign or magnitude of the central charge contribution, re-examine Λ_eff^(Q) and the central tidal isotropy claim in Eq. (87).","verdict_should_be":"CONDITIONAL","load_bearing_attack":"All charged results (ISCO values in Fig. 13, tidal components in Eqs. (75)-(76), and the deviation-vector plots in Figs. 19, 23, and 25) depend on the charged metric in Eqs. (18)-(19). As printed, that metric is internally inconsistent with the paper's own stated classical limits. Expanding Eq. (19) for r ≫ ℓ0 gives F(r) = 5/8 + (3/4)ℓ0²/r² − (9π/32)ℓ0³/r³ + O(ℓ0⁴/r⁴). Substituting into Eq. (18), the charge term behaves as (5/8)Q²/r² − (1/2)Q²ℓ0²/r⁴ + O(ℓ0³/r⁵), not Q²/r² + O(1/r³) as asserted in Eqs. (20) and (26). Even in the strict limit ℓ0 → 0 at fixed r, F → 5/8, so the claimed Reissner-Nordström limit (20) fails. Near r = 0, the same F has F(0) = 3(2 + π)/16 > 0, making the charge contribution to f positive at leading order, whereas Eq. (21) requires the charge term −3πQ²r²/(16ℓ0⁴), i.e. F(0) = −3π/16. Thus Eqs. (18)-(19) as written do not reproduce the regularized charged solution on which Secs. III-V rely. If Eq. (19) is a transcription error from Ref. [32], the charged numerical section must be recomputed with the correct F; if it is accurate, the paper's charged limiting statements are wrong. Either way this is a load-bearing unresolved inconsistency, not a stylistic gap.","agreement_with_reader":"partial"},"referee_report":{"model":"deepseek/deepseek-v4-flash","summary":"The paper presents a systematic study of geodesic motion, circular orbits, tidal forces, and geodesic deviation in the neutral and electrically charged T-duality-regularized black hole spacetimes of Nicolini–Spallucci–Wondrak [29] and Gaete–Jusufi–Nicolini [32]. For the neutral geometry the paper derives the horizon structure (including the extremal scale ℓ₀,crit = 4M/(3√3)), the photon-sphere condition, the ISCO condition, the tidal components k1 = −f″/2 and k2 = −f′/(2r), and the accumulated deformation of radial congruences under two initial-condition schemes; these derivations are internally consistent and reduce correctly to the Schwarzschild limit. For the charged geometry the paper repeats the analysis using the imported metric (18)–(19) and reports quantitative results (horizon diagram, extremal curve, photon orbits, ISCO values, tidal zeros and extrema, deviation-vector amplitudes) together with the claim that the Reissner–Nordström limit and a regularized charged core are recovered. The central physical claims are that the T-duality scale makes the tidal tensor finite and isotropic at the center with common value Λ_eff/3, that an intermediate simultaneous-compression region exists, and that both ℓ₀ and Q suppress the accumulated radial stretching while the angular deformation is nearly insensitive to Q. Sections III–V also report that charged classical limits are recovered appropriately in Eqs. (20), (26), (79), (81)–(82), and (85)–(87).","tokens_in":34179,"tokens_out":26546,"duration_ms":186373,"significance":"The neutral-sector analysis is a solid and reproducible contribution: I verified Eqs. (8), (16)–(17), (42), (48), and (77)–(78) by direct computation from the stated metric, and the identification of a finite, isotropic tidal core preceded by a simultaneous-compression band is a clean, correctly derived result for the regular neutral spacetime. The paper is transparent about its numerical root-finding and fits no parameters; the only free parameters (ℓ₀, Q) are physical inputs of the model. However, roughly half of the paper's quantitative claims belong to the charged sector, and that sector is built on a metric that fails the paper's own classical-limit tests (Sec. II B). Until the charged metric is repaired and the charged numerics are recomputed, the charged ISCO, photon-orbit, tidal, and deviation-vector results cannot be regarded as describing the charged T-duality black hole advertised in the title and abstract, and the abstract's statement that the classical limits are recovered appropriately is false for the charged sector as printed. The overall significance therefore hinges on a load-bearing correction that is within the manuscript's scope.","major_comments":[{"comment":"The printed charged metric does not have the claimed Reissner–Nordström limit. Expanding the F(r) of Eq. (19) for r ≫ ℓ₀ gives F(r) = 5/8 + (3/4)ℓ₀²/r² − (9π/32)ℓ₀³/r³ + O(ℓ₀⁴/r⁴), so the charge term in Eq. (18) behaves as (5/8)Q²/r² − (1/2)Q²ℓ₀²/r⁴ + O(ℓ₀³/r⁵). In particular F → 5/8 as ℓ₀ → 0 at fixed r, so Eq. (20) should read f → 1 − 2M/r + (5/8)Q²/r², not f → 1 − 2M/r + Q²/r². Moreover the 1/r³ coefficient −9πQ²ℓ₀/32 claimed in Eq. (26) cannot arise from this F: the ℓ₀³ term in F appears in the charge term only at order 1/r⁵. This is a direct contradiction between printed equations, not a missing derivation, and it invalidates the stated RN asymptotics for all subsequent charged expansions.","section":"Sec. II B, Eqs. (18)–(20) and (26)","authors_acknowledge":null,"authors_acknowledge_p":null},{"comment":"The central small-r behavior asserted in Eq. (21) is also contradicted by the printed metric. Expanding F(r) for r ≪ ℓ₀, using arctan(r/ℓ₀) ≈ r/ℓ₀ − r³/(3ℓ₀³) and (r²+ℓ₀²)^{3/2} ≈ ℓ₀³(1 + 3r²/(2ℓ₀²)), the 1/r² pieces of the second and third terms of Eq. (19) cancel, giving F(0) = 5/8 + (3π−7)/16 = 3(1+π)/16 > 0. The charge contribution to f(r) near r = 0 is therefore +3(1+π)Q²r²/(16ℓ₀⁴), with the opposite sign to the −3πQ²r²/(16ℓ₀⁴) required by Eq. (21). Consequently the effective cosmological constant (23), the de Sitter/anti-de Sitter core classification, the critical condition 32Mℓ₀ = 3πQ², and the curvature invariants (24)–(25) are all inconsistent with the metric as printed. The sign and magnitude of the central charge correction must be corrected before any charged-core claim can stand.","section":"Sec. II B, Eqs. (18)–(21)","authors_acknowledge":null,"authors_acknowledge_p":null},{"comment":"Every charged result inherits the inconsistency of Eqs. (18)–(19). I verified that the charged tidal formulas (75)–(76) are algebraically consistent with the printed metric (the F, F′, F″ structure is correct), so the derivation pipeline is not the problem; the input metric is. But Eqs. (79), (81)–(82), (85)–(86), and the isotropy value (87) are therefore wrong as printed, and the charged numerical results — the horizon and extremal data of Figs. 2–3, the photon-sphere curves of Figs. 6–7 with Q_ph,crit ≈ 1.0517M, the ISCO values of Figs. 9, 11, and 13, the tidal radii of Figs. 15–17, and the deviation-vector amplitudes of Figs. 19, 21, 23, and 25 — were computed from a model whose asymptotic charge term is (5/8)Q²/r² and whose central charge term has the wrong sign. As printed, these results do not describe the charged T-duality black hole whose limits the paper states. The authors must either replace F(r) with the correct expression from Ref. [32] and recompute the full charged sector, or explicitly re-scope the paper to the printed metric and correct all the limit statements, including the abstract's claim that the classical limits are recovered appropriately.","section":"Secs. III–V, charged-sector results","authors_acknowledge":null,"authors_acknowledge_p":null}],"minor_comments":[{"comment":"The sentence stating that the metric function depends on ℓ₀ only through ℓ₀², so that ℓ₀ ≥ 0 can be assumed, is made before the charged metric is introduced; the charged function F(r) in Eq. (19) contains ℓ₀ to the first power, so the statement should be explicitly restricted to the neutral geometry.","section":"Sec. II A 1","authors_acknowledge":null,"authors_acknowledge_p":null},{"comment":"The photon-sphere analysis for the charged geometry overlaps with the null-geodesic study of Ref. [65], which is cited only in the introduction; a brief comparison of the present photon-sphere radii (Figs. 6–7) with those of Ref. [65] would help the reader identify what is new.","section":"Sec. I and Sec. III C","authors_acknowledge":null,"authors_acknowledge_p":null},{"comment":"The captions state that the markers indicate the inner and outer horizons and the turning radius, but for horizonless parameter values (e.g., ℓ₀ = 0.9M in Fig. 14) the horizon markers do not exist; the captions should say that the horizon radii are shown where defined, as is already done in the captions of Figs. 19, 21, 23, and 25.","section":"Captions of Figs. 14 and 15","authors_acknowledge":null,"authors_acknowledge_p":null}],"recommendation":"major_revision","confidential_remarks":"The reader's accept verdict presupposed that the charged metric quoted from Ref. [32] was physically valid. The skeptic's test shows that the problem is internal to the manuscript: Eqs. (20) and (21) can be checked directly against Eq. (19) without consulting Ref. [32], and both checks fail. I could not reproduce the charged figures because they depend on the as-yet-uncorrected F(r), so the quantitative claims in the charged sector are presently unreliable. This is fixable within scope (correct F, regenerate the charged sector, re-check the limits), hence major_revision rather than reject; but I would not accept the present version. I also note that a large fraction of the bibliography consists of very recent arXiv preprints, including several by the authors' own collaboration; the authors should verify that the cited preprints are the definitive sources for the claims attributed to them."},"author_rebuttal":null,"desk_editor":{"model":"deepseek/deepseek-v4-flash","letter":"Two things you should know. First, the neutral-sector tidal analysis is genuinely new and it checks out: closed-form k1 and k2 for the T-duality metric, explicit roots and extrema, and a real intermediate band of simultaneous radial and angular compression. Second, the charged sector as printed is built on a metric that fails its own limits. F(r) in Eq. (19) tends to 5/8 at infinity, so the charge term in Eq. (18) behaves as (5/8)Q^2/r^2, not Q^2/r^2 as Eqs. (20) and (26) claim. Near r = 0 the same F tends to a positive O(1) constant (I get 3(1+pi)/16; the stress-test says 3(2+pi)/16; the exact value does not matter), while Eq. (21) requires F(0) = -3pi/16. Both limits cannot follow from the same function. Either Eq. (19) is a bad transcription from Ref. [32] or the limiting statements are wrong; either way, every charged result (ISCOs, tidal zeros, deviation plots, the claimed RN tidal limits in Eqs. (79)-(82)) inherits the problem, and those sections must be recomputed from the correct F. This is not the ordinary \"imported from the literature\" situation: importing the geometry from [32] is legitimate, but the imported function contradicts the paper's own equations. The reader's ACCEPT is too generous on the charged half; the algebra from the stated metric was checked correctly, but the stated metric itself is the problem.\n\nCredit where due. I re-checked the neutral metric, the horizon critical values, the tidal roots and extrema, the ISCO condition, and the Schwarzschild limits; all consistent. The framework is the standard Crispino tetrad construction, applied carefully, and the neutral closed forms are the real new content.\n\nSoft spots in proportion. The charged-metric inconsistency is load-bearing and serious. Beyond it: the numerics ship no code or convergence data; the charge-insensitivity of the angular deviation is a numerical observation with no analytic explanation; and the paper itself defers observational signatures to future work, so with Planck-scale l0 most of the new tidal structure sits inside the horizon - acknowledged, but it caps the significance.\n\nWho this is for: the regular-black-hole tidal community. The neutral calculation deserves citation once the charged part is fixed. I would send this to a referee rather than desk-reject - the neutral algebra is checkable and the charged error is likely fixable - but the revision is heavy: correct F, rerun everything Q-dependent, re-derive the claimed limits.","headline":"Neutral-sector tidal analysis is new and checks out; the charged metric as printed fails its own Reissner-Nordstrom and near-origin limits, so all Q-dependent results need recomputation.","tokens_in":34735,"tokens_out":15473,"would_cite":true,"duration_ms":112789,"reading_group":"maybe","serious_thinker":"yes","would_accept_peer_review":true},"pith_extraction":{"msc":["83C57","83C10","83C75"],"pacs":["04.70.-s","04.20.-q"],"model":"deepseek/deepseek-v4-flash","headline":"In T-duality-regularized black holes, tidal forces stay finite at the core and become isotropic, with an intermediate region where infalling matter is compressed in all three spatial directions.","keywords":["T-duality","regular black hole","tidal forces","geodesic deviation","photon sphere","innermost stable circular orbit","zero-point length","string theory"],"falsifier":"Recompute the Einstein tensor for the charged metric (18)-(19) and compare it, component by component, with the stress-energy tensor that the T-duality-regularized electromagnetic sector is claimed to source; a mismatch would invalidate the charged geometry and all charged tidal conclusions. On the observational side, the prediction that the ISCO radius drops below $6M$ once $\\ell_0$ reaches a few tenths of $M$ means that a measured inner accretion-disk edge at $6M$ for a non-rotating object would bound $\\ell_0$ to be very small, while a smaller edge would support the regularization.","tokens_in":35175,"feed_emoji":"🕳️","tokens_out":10981,"duration_ms":83648,"temperature":0.7,"pith_summary":"This paper asks what happens to orbits and to falling bodies when the black hole's central singularity is replaced by a smooth core, as string T-duality suggests. Working with the neutral and electrically charged T-duality-regularized metrics, characterized by a minimum length scale $\\ell_0$, the authors compute the photon-sphere, circular-orbit, and ISCO structure and then the tidal forces experienced by observers in radial free fall. They establish that the tidal components remain finite at $r=0$ and approach the common isotropic value $\\Lambda_{\\rm eff}/3$, that an intermediate region of simultaneous radial and angular compression appears inside the geometry, and that both $\\ell_0$ and the electric charge $Q$ suppress the accumulated radial stretching of an infalling congruence while leaving the angular deformation almost untouched. The Schwarzschild and Reissner-Nordström limits are recovered smoothly as $\\ell_0\\to 0$.","feed_headline":"T-duality core makes black hole tidal forces finite","feed_subtitle":"A string-inspired minimum length caps tidal stretching, adds an all-compression zone, and shrinks the ISCO.","key_machinery":"The machinery is a single metric function $f(r)$: $f(r)=1-2Mr^2/(r^2+\\ell_0^2)^{3/2}$ in the neutral case, extended in the charged case by a term $Q^2 r^2 F(r)/(r^2+\\ell_0^2)^2$ with a specified $F(r)$ encoding the regularized electromagnetic sector. Everything else derives from $f$ and its first two derivatives: the tidal components in the radial free-fall tetrad are $k_1=-f''/2$ and $k_2=-f'/(2r)$; the geodesic dynamics follow from the effective potential $V_{\\rm eff}(r)=f(r)(\\kappa+L^2/r^2)$, whose extrema fix the photon sphere and the stable and unstable circular orbits and whose inflection point $V_m'=V_m''=0$ fixes the ISCO; and the accumulated deformation follows from integrating the decoupled deviation equations $d^2\\xi^{\\hat r}/d\\tau^2=k_1\\xi^{\\hat r}$ and $d^2\\xi^{\\hat i}/d\\tau^2=k_2\\xi^{\\hat i}$ along the radial infall. The same function therefore carries both the local (tidal tensor) and the global (deviation vector) results.","core_discovery":"The central claim is that the T-duality minimum length scale does more than remove the curvature singularity: it restructures the strong-field tidal response. In the free-fall tetrad frame the tidal tensor has radial component $k_1=-f''/2$ and angular component $k_2=-f'/(2r)$, and for the neutral geometry both tend to $2M/\\ell_0^3=\\Lambda_{\\rm eff}/3$ at the origin, so the tidal field is isotropic at the core; the charged geometry preserves this isotropy with $\\Lambda_{\\rm eff}^{(Q)}=6M/\\ell_0^3-9\\pi Q^2/16\\ell_0^4$, which can change sign and flip the core between de Sitter-like and anti-de Sitter-like behavior at $32M\\ell_0=3\\pi Q^2$. Between the outer and inner regions there is a band, bounded by $r_{k_2}=\\sqrt{2}\\,\\ell_0$ and by the outer zero $r_{k_1}^{(2)}$ of the radial component, in which $k_1<0$ and $k_2<0$ simultaneously: a freely falling body is squeezed in every direction. On the orbital side, the paper shows that the photon-sphere radius and the ISCO radius both decrease monotonically with $\\ell_0$ and with $Q$, and that circular photon orbits persist into a finite window of horizonless configurations before the stable and unstable branches merge. Integrating the geodesic deviation equations for two sets of initial conditions, the paper finds that increasing $\\ell_0$ or $Q$ progressively reduces the maximum radial separation of nearby geodesics, whereas the angular separation is nearly $Q$-independent and follows $\\xi^{\\hat i}/\\xi^{\\hat i}(b)=r/b$ in the zero-initial-velocity scenario.","pith_inferences":["A likely generic message: any regular black hole with a de Sitter-like core will share the isotropic central limit $k_1,k_2\\to\\Lambda_{\\rm eff}/3$, so the central tidal value mainly measures the regularization scale $\\ell_0$ rather than the specific model, while the discriminating information sits in the subleading $r^2$ terms and the sign-change radii.","If the charged metric is correct, the radial tidal sign change emerges outside the horizon at $Q/M\\simeq 0.8194$ for $\\ell_0=0.5M$ while the angular zero only reaches the horizon at extremality, an asymmetry that could be probed through observations of infalling matter in a way the local tidal profiles alone cannot.","The exact linear law $\\xi^{\\hat i}/\\xi^{\\hat i}(b)=r/b$ in the first initial-condition scenario is an artifact of that setup rather than a property of the spacetime; extending the deviation analysis to circular-orbit observers, which the authors list as future work, would very likely reveal charge sensitivity in the angular channel.","Because the ISCO shrinks monotonically with $\\ell_0$ and $Q$, a natural testable extension is to invert observed disk inner edges into bounds on $\\ell_0/M$: for a non-rotating object, any inner edge below $6M$ would already signal a regularization of this type."],"forward_implications":["A radially infalling observer in these spacetimes never encounters divergent tidal stress: the stretching maximum is finite, occurs at a radius set by $\\ell_0$, and is followed by compression and then an isotropic central regime.","Classical spaghettification is replaced by a stretch-compress-stretch-isotropic sequence, with an intervening band in which the body is compressed in all three spatial directions.","Photon rings and accretion-disk inner edges form at smaller radii than in Schwarzschild or Reissner-Nordström, so shadow and ISCO geometry carry an imprint of $\\ell_0$ and $Q$.","Horizonless T-duality configurations can still possess photon spheres over a finite parameter window, so shadow formation alone does not certify the presence of a horizon.","Because charge suppresses accumulated radial stretching while barely affecting angular deformation, tidal-disruption signatures of charged T-duality objects should appear preferentially in the radial channel."],"supporting_citations":[{"why":"Supplies the neutral T-duality-regularized black hole metric and its effective matter distribution, the starting geometry of the whole analysis.","marker":"[29]"},{"why":"Supplies the charged T-duality solution with the function $F(r)$ on which every charged orbital and tidal result is built.","marker":"[32]"},{"why":"Introduces the path-integral duality $ds \\leftrightarrow \\ell_0^2/ds$ that motivates the zero-point (minimum) length scale.","marker":"[27]"},{"why":"Implements the duality through a modified scalar propagator, the basis of the regularized gravitational potential used to derive the metric.","marker":"[28]"},{"why":"Supplies the tetrad formalism, the Reissner-Nordström tidal components, and the two initial-condition scenarios adopted for the geodesic deviation analysis.","marker":"[45]"},{"why":"Extends the tidal framework to a charged regular (Hayward) black hole, the methodological template this paper follows for the T-duality geometry.","marker":"[46]"},{"why":"Provides the black-bounce tidal stretching and compression analysis against which the T-duality tidal regimes are compared.","marker":"[48]"},{"why":"Studies geodesic completeness of the neutral T-duality solution through the Raychaudhuri equation, motivating the congruence and deviation analysis presented here.","marker":"[69]"}],"fun_headline_variants":["T-duality black holes squeeze freely falling bodies from all sides","String-inspired core makes black hole tides finite and isotropic","Quantum-regularized black holes shrink photon sphere and ISCO","T-duality charge flips black hole core between dS and AdS","Radial stretching suppressed in T-duality black holes"],"cache_read_input_tokens":0,"weakest_assumption_plain":"Every charged result in the paper takes as given the published metric in Eqs. (18)-(19), including its function $F(r)$ and its derivatives, without rederiving it; if that construction is not the true regularized charged solution, the charged ISCO values, tidal sign-change radii, and deviation-vector curves would all shift.","fun_headline_variants_meta":{"raw":{"variants":["T-duality black holes squeeze freely falling bodies from all sides","String-inspired core makes black hole tides finite and isotropic","Quantum-regularized black holes shrink photon sphere and ISCO","T-duality charge flips black hole core between dS and AdS","Radial stretching suppressed in T-duality black holes"]},"model":"deepseek/deepseek-v4-flash","effort":"low","cost_usd":0.000104,"raw_usage":{"cost":0.0001035762,"is_byok":false,"cost_details":{"upstream_inference_cost":0.0001035762,"upstream_inference_prompt_cost":3.42342e-05,"upstream_inference_completions_cost":6.9342e-05},"total_tokens":1686,"prompt_tokens":1305,"completion_tokens":381,"prompt_tokens_details":{"audio_tokens":0,"video_tokens":0,"cached_tokens":1161,"cache_write_tokens":0},"completion_tokens_details":{"audio_tokens":0,"image_tokens":0,"reasoning_tokens":309}},"tokens_in":1305,"tokens_out":381,"cost_source":"openrouter_usage","duration_ms":9715,"image_pages":[],"temperature":1.0,"billed_attempts":1,"reasoning_tokens":309,"transport_provider":"openrouter","cache_read_input_tokens":0,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-10-28T08:03:28.318940+00:00","model_set":{"reader":"deepseek/deepseek-v4-flash"},"falsifier":"Recompute the Einstein tensor for the charged metric (18)-(19) and compare it, component by component, with the stress-energy tensor that the T-duality-regularized electromagnetic sector is claimed to source; a mismatch would invalidate the charged geometry and all charged tidal conclusions. On the observational side, the prediction that the ISCO radius drops below $6M$ once $\\ell_0$ reaches a few tenths of $M$ means that a measured inner accretion-disk edge at $6M$ for a non-rotating object would bound $\\ell_0$ to be very small, while a smaller edge would support the regularization.","supporting_citations":[{"cited_title":null,"cited_arxiv_id":null,"evidence_quote":"Supplies the neutral T-duality-regularized black hole metric and its effective matter distribution, the starting geometry of the whole analysis."},{"cited_title":"Finite electrodynamics from T-duality","cited_arxiv_id":"2202.09311","evidence_quote":"Supplies the charged T-duality solution with the function $F(r)$ on which every charged orbital and tidal result is built."},{"cited_title":"Padmanabhan, Duality and zero point length of space-time, Phys","cited_arxiv_id":null,"evidence_quote":"Introduces the path-integral duality $ds \\leftrightarrow \\ell_0^2/ds$ that motivates the zero-point (minimum) length scale."},{"cited_title":"Padmanabhan, Hypothesis of path integral duality","cited_arxiv_id":null,"evidence_quote":"Implements the duality through a modified scalar propagator, the basis of the regularized gravitational potential used to derive the metric."},{"cited_title":null,"cited_arxiv_id":null,"evidence_quote":"Supplies the tetrad formalism, the Reissner-Nordström tidal components, and the two initial-condition scenarios adopted for the geodesic deviation analysis."},{"cited_title":"Tidal Forces in Reissner-Nordstr\\\"om Spacetimes","cited_arxiv_id":"1602.07232","evidence_quote":"Extends the tidal framework to a charged regular (Hayward) black hole, the methodological template this paper follows for the T-duality geometry."},{"cited_title":"Tidal Forces in Dyonic Reissner-N¨ ordstrom Black Hole, Commun. Theor. Phys. 69, 257","cited_arxiv_id":null,"evidence_quote":"Provides the black-bounce tidal stretching and compression analysis against which the T-duality tidal regimes are compared."},{"cited_title":"Black bounce as a quantum correction from string T-duality: Thermodynamics, en- ergy conditions, and observational imprints from EHT,","cited_arxiv_id":null,"evidence_quote":"Studies geodesic completeness of the neutral T-duality solution through the Raychaudhuri equation, motivating the congruence and deviation analysis presented here."}],"review_version":1}