Fortuity beyond counting: an explicit construction
Pith reviewed 2026-06-26 15:54 UTC · model grok-4.3
The pith
In the D1D5 CFT an explicit non-vanishing three-point coupling links two monotone states to one fortuitous state.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
We find an explicit example of a non-vanishing coupling between two monotone and a fortuitous state, providing evidence that the two sectors are dynamically connected. This follows from deriving the primary states via supercharge actions at different central charges, imposing that the inter-theory map commutes with those supercharges, and then computing the protected three-point correlators that become possible once the states are correctly identified.
What carries the argument
The map between theories of different central charges that commutes with the supercharges defining the cochain complex, which fixes the identification of monotone and fortuitous states before three-point couplings are evaluated.
If this is right
- The identification of monotone and fortuitous states must preserve the action of the supercharges.
- Agreement between free and gravity regimes imposes concrete constraints on how states at different central charges are matched.
- The monotone and fortuitous sectors are not dynamically decoupled.
- Protected three-point functions can mix the two sectors once the commuting map is used.
Where Pith is reading between the lines
- The same commuting-map requirement may constrain higher-point correlators or other protected quantities.
- The explicit primary states obtained at (h,j)=(1,0) could be reused to test additional selection rules between the sectors.
- If the map exists at this level it may extend to other symmetric-orbifold points or to related CFTs with varying central charge.
Load-bearing premise
A map relating theories with different central charges can be defined so that it commutes with the supercharges defining the cochain complex.
What would settle it
An independent calculation of the same three-point function in the gravity regime that returns exactly zero would show the sectors remain decoupled.
read the original abstract
We reconsider the "fortuity'' mechanism in the D1D5 CFT focusing on the K3 symmetric orbifold. Going beyond the counting of BPS states, we investigate perturbatively how the explicit form of the BPS cohomologies is modified by the twist-two deformations. We calculate the action of the supercharges in the sector $(h,j)=(1,0)$ for different values of the central charge and derive explicit expressions for the primary states. Equipped with this information, we compare some protected three-point couplings in the free and the gravity regime. We show that agreement between the two descriptions imposes non-trivial constraints on the identification of monotone and fortuitous states. In particular, we argue that the map relating theories with different values of the central charge must and can be defined so as to commute with the supercharges that define the cochain complex. We then study the three-point correlators between the fortuitous and monotone states identified in our analysis to assess whether the two sectors are dynamically decoupled. We find an explicit example of a non-vanishing coupling between two monotone and a fortuitous state, providing evidence that the two sectors are dynamically connected.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The manuscript reconsiders the fortuity mechanism in the D1D5 CFT on the K3 symmetric orbifold. It computes the action of supercharges on twist-two deformed states in the (h,j)=(1,0) sector at different central charges, derives explicit expressions for the primary states, argues that a map between theories of different central charges can and must be defined to commute with the supercharges defining the cochain complex, and evaluates protected three-point couplings to exhibit an explicit non-vanishing correlator between two monotone states and one fortuitous state, thereby providing evidence that the two sectors are dynamically connected.
Significance. If the central claim holds, the work supplies a concrete step beyond BPS state counting by furnishing explicit primary-state expressions and a non-vanishing three-point function that links the monotone and fortuitous sectors. The explicit supercharge-action calculations constitute a useful technical contribution that could support further protected-correlator analyses in AdS3/CFT2.
major comments (2)
- [Abstract] Abstract (paragraph on identification constraints): the claim that a map relating theories with different central charges 'must and can be defined' so that it commutes with the supercharges is asserted without an explicit construction of the map, without a verification that commutation holds on the full basis of states, and without a check that the resulting identification is stable under addition of Q-exact terms. Because the reported non-vanishing coupling between monotone and fortuitous states rests directly on this identification, the absence of these verifications renders the dynamical-connection conclusion provisional.
- [Abstract] Abstract (final paragraph): the explicit example of a non-vanishing three-point coupling is presented as evidence that the sectors are dynamically connected, yet the computation inherits the identification ambiguity noted above; if the commuting-map condition under-constrains the map or permits Q-exact shifts, the sign or vanishing of the correlator can change, so the load-bearing step requires an explicit demonstration that the chosen representatives yield a protected, unambiguous result.
Simulated Author's Rebuttal
We thank the referee for their careful reading of the manuscript and for the constructive comments. We address the two major comments point by point below, clarifying the construction of the identification map and the status of the three-point function. We indicate where revisions will be incorporated.
read point-by-point responses
-
Referee: [Abstract] Abstract (paragraph on identification constraints): the claim that a map relating theories with different central charges 'must and can be defined' so that it commutes with the supercharges is asserted without an explicit construction of the map, without a verification that commutation holds on the full basis of states, and without a check that the resulting identification is stable under addition of Q-exact terms. Because the reported non-vanishing coupling between monotone and fortuitous states rests directly on this identification, the absence of these verifications renders the dynamical-connection conclusion provisional.
Authors: The map is constructed in Sections 2 and 3 by explicitly computing the action of the supercharges on the twist-two deformed states at different central charges and deriving the resulting primary states. Commutation with the supercharges is verified on the full basis of states in the (h,j)=(1,0) sector. Stability under Q-exact redefinitions follows because the three-point functions are protected correlators. We will revise the abstract to reference these explicit constructions and verifications in the main text. revision: partial
-
Referee: [Abstract] Abstract (final paragraph): the explicit example of a non-vanishing three-point coupling is presented as evidence that the sectors are dynamically connected, yet the computation inherits the identification ambiguity noted above; if the commuting-map condition under-constrains the map or permits Q-exact shifts, the sign or vanishing of the correlator can change, so the load-bearing step requires an explicit demonstration that the chosen representatives yield a protected, unambiguous result.
Authors: The three-point function is a protected quantity in the BPS sector and is therefore invariant under Q-exact shifts of the representatives. Section 4 shows that the non-vanishing result is obtained precisely for the states selected by the commuting-map condition. We will add a clarifying paragraph in the revised manuscript emphasizing that the protection guarantees the result is unambiguous. revision: partial
Circularity Check
No significant circularity; explicit computations drive the result
full rationale
The derivation begins with direct calculation of supercharge actions on twist-two deformed states at varying central charges, yielding explicit primary-state expressions in the (h,j)=(1,0) sector. These expressions are then used to evaluate protected three-point couplings, whose agreement between free and gravity regimes supplies constraints that fix the form of the central-charge map (required to commute with the supercharges). The final non-vanishing coupling is obtained by substituting the resulting state representatives into the correlator; none of these steps reduces by definition or by fitted-parameter renaming to the input data, nor does any load-bearing premise rest solely on a self-citation whose content is unverified. The construction is therefore self-contained against external benchmarks.
Axiom & Free-Parameter Ledger
Reference graph
Works this paper leans on
-
[1]
The large N limit of superconformal field theories and supergravity,
J. M. Maldacena, “The large N limit of superconformal field theories and supergravity,”Adv. Theor. Math. Phys.2(1998) 231–252,hep-th/9711200
Pith/arXiv arXiv 1998
-
[2]
Black holes and the butterfly effect,
S. H. Shenker and D. Stanford, “Black holes and the butterfly effect,”JHEP03 (2014) 067,1306.0622
Pith/arXiv arXiv 2014
-
[3]
No ensemble averaging below the black hole threshold,
J.-M. Schlenker and E. Witten, “No ensemble averaging below the black hole threshold,”JHEP07(2022) 143,2202.01372
arXiv 2022
-
[4]
Y. Chen, H. W. Lin, and S. H. Shenker, “BPS chaos,”SciPost Phys.18(2025), no. 2, 072,2407.19387
Pith/arXiv arXiv 2025
-
[5]
Bubbling AdS space and 1/2 BPS geometries,
H. Lin, O. Lunin, and J. M. Maldacena, “Bubbling AdS space and 1/2 BPS geometries,”JHEP10(2004) 025,hep-th/0409174
Pith/arXiv arXiv 2004
-
[6]
Metric of the multiply wound rotating string,
O. Lunin and S. D. Mathur, “Metric of the multiply wound rotating string,”Nucl. Phys.B610(2001) 49–76,hep-th/0105136
Pith/arXiv arXiv 2001
-
[7]
Fuzzballs with internal excitations,
I. Kanitscheider, K. Skenderis, and M. Taylor, “Fuzzballs with internal excitations,”JHEP06(2007) 056,0704.0690
Pith/arXiv arXiv 2007
-
[8]
Supersymmetric AdS(5) black holes,
J. B. Gutowski and H. S. Reall, “Supersymmetric AdS(5) black holes,”JHEP02 (2004) 006,hep-th/0401042. 26
Pith/arXiv arXiv 2004
-
[9]
General supersymmetric AdS(5) black holes,
J. B. Gutowski and H. S. Reall, “General supersymmetric AdS(5) black holes,” JHEP04(2004) 048,hep-th/0401129
Pith/arXiv arXiv 2004
-
[10]
Microscopic Origin of the Bekenstein-Hawking Entropy,
A. Strominger and C. Vafa, “Microscopic Origin of the Bekenstein-Hawking Entropy,”Phys. Lett.B379(1996) 99–104,hep-th/9601029
Pith/arXiv arXiv 1996
-
[11]
Habemus Superstratum! A constructive proof of the existence of superstrata,
I. Bena, S. Giusto, R. Russo, M. Shigemori, and N. P. Warner, “Habemus Superstratum! A constructive proof of the existence of superstrata,”JHEP05 (2015) 110,1503.01463
Pith/arXiv arXiv 2015
-
[12]
Asymptotically-flat supergravity solutions deep inside the black-hole regime,
I. Bena, S. Giusto, E. J. Martinec, R. Russo, M. Shigemori, D. Turton, and N. P. Warner, “Asymptotically-flat supergravity solutions deep inside the black-hole regime,”JHEP02(2018) 014,1711.10474
Pith/arXiv arXiv 2018
- [13]
-
[14]
Smooth horizonless geometries deep inside the black-hole regime,
I. Bena, S. Giusto, E. J. Martinec, R. Russo, M. Shigemori, D. Turton, and N. P. Warner, “Smooth horizonless geometries deep inside the black-hole regime,”Phys. Rev. Lett.117(2016), no. 20, 201601,1607.03908
Pith/arXiv arXiv 2016
-
[15]
Holographic covering and the fortuity of black holes,
C.-M. Chang and Y.-H. Lin, “Holographic covering and the fortuity of black holes,”2402.10129
-
[16]
1/16 BPS states inN= 4 super-Yang-Mills theory,
C.-M. Chang and X. Yin, “1/16 BPS states inN= 4 super-Yang-Mills theory,” Phys. Rev. D88(2013), no. 10, 106005,1305.6314
Pith/arXiv arXiv 2013
-
[17]
Words to describe a black hole,
C.-M. Chang and Y.-H. Lin, “Words to describe a black hole,”JHEP02(2023) 109,2209.06728
arXiv 2023
-
[18]
The shape of non-graviton operators for SU(2),
S. Choi, S. Kim, E. Lee, and J. Park, “The shape of non-graviton operators for SU(2),”JHEP09(2024) 029,2209.12696
arXiv 2024
-
[19]
C.-M. Chang, Y. Chen, B. S. Sia, and Z. Yang, “Fortuity in SYK models,”JHEP 08(2025) 003,2412.06902
arXiv 2025
-
[20]
A. Belin, P. Singh, R. Vadala, and A. Zaffaroni, “Fortuity in ABJM,”2512.04146
-
[21]
Structure of loop space at finite N,
R. de Mello Koch and A. Jevicki, “Structure of loop space at finite N,”JHEP06 (2025) 011,2503.20097
arXiv 2025
-
[22]
Bosonic fortuity in vector models,
R. de Mello Koch, A. Ghosh, and H. J. R. Van Zyl, “Bosonic fortuity in vector models,”JHEP06(2025) 246,2504.14181. 27
arXiv 2025
- [23]
-
[24]
C.-M. Chang, Y.-H. Lin, and H. Zhang, “Fortuity in the D1-D5 system,” 2501.05448
-
[25]
M. R. R. Hughes and M. Shigemori, “Fortuity and supergravity,”JHEP03(2026) 130,2505.14888
arXiv 2026
-
[26]
Fortuity and R-charge concentration in the D1-D5 CFT,
C.-M. Chang and H. Zhang, “Fortuity and R-charge concentration in the D1-D5 CFT,”2511.23294
-
[27]
Signatures of Quantum Chaos in the D1D5 System,
H. Zhang, “Signatures of Quantum Chaos in the D1D5 System,”2605.18725
-
[28]
A non-renormalization theorem for chiral primary 3-point functions,
M. Baggio, J. de Boer, and K. Papadodimas, “A non-renormalization theorem for chiral primary 3-point functions,”JHEP07(2012) 137,1203.1036
Pith/arXiv arXiv 2012
-
[29]
Proving the PP wave / CFT(2) duality,
E. Gava and K. Narain, “Proving the PP wave / CFT(2) duality,”JHEP0212 (2002) 023,hep-th/0208081
Pith/arXiv arXiv 2002
-
[30]
Effect of the twist operator in the D1D5 CFT,
Z. Carson, S. Hampton, S. D. Mathur, and D. Turton, “Effect of the twist operator in the D1D5 CFT,”JHEP1408(2014) 064,1405.0259
Pith/arXiv arXiv 2014
-
[31]
Effect of the deformation operator in the D1D5 CFT,
Z. Carson, S. Hampton, S. D. Mathur, and D. Turton, “Effect of the deformation operator in the D1D5 CFT,”JHEP01(2015) 071,1410.4543
Pith/arXiv arXiv 2015
-
[32]
Second order effect of twist deformations in the D1D5 CFT,
Z. Carson, S. Hampton, and S. D. Mathur, “Second order effect of twist deformations in the D1D5 CFT,”JHEP04(2016) 115,1511.04046
Pith/arXiv arXiv 2016
-
[33]
Full action of two deformation operators in the D1D5 CFT,
Z. Carson, S. Hampton, and S. D. Mathur, “Full action of two deformation operators in the D1D5 CFT,”JHEP11(2017) 096,1612.03886
Pith/arXiv arXiv 2017
-
[34]
Lifting of states in 2-dimensionalN= 4 supersymmetric CFTs,
B. Guo and S. D. Mathur, “Lifting of states in 2-dimensionalN= 4 supersymmetric CFTs,”JHEP10(2019) 155,1905.11923
arXiv 2019
-
[35]
Lifting of level-1 states in the D1D5 CFT,
B. Guo and S. D. Mathur, “Lifting of level-1 states in the D1D5 CFT,”JHEP03 (2020) 028,1912.05567
arXiv 2020
-
[36]
Lifting at higher levels in the D1D5 CFT,
B. Guo and S. D. Mathur, “Lifting at higher levels in the D1D5 CFT,”JHEP11 (2020) 145,2008.01274
arXiv 2020
-
[37]
Universal lifting in the D1-D5 CFT,
B. Guo, M. R. R. Hughes, S. D. Mathur, and M. Mehta, “Universal lifting in the D1-D5 CFT,”JHEP10(2022) 148,2208.07409. 28
arXiv 2022
-
[38]
Perturbing the symmetric orbifold from the worldsheet,
M.-A. Fiset, M. R. Gaberdiel, K. Naderi, and V. Sriprachyakul, “Perturbing the symmetric orbifold from the worldsheet,”JHEP07(2023) 093,2212.12342
arXiv 2023
-
[39]
Lifting of two-mode states in the D1-D5 CFT,
M. R. R. Hughes, S. D. Mathur, and M. Mehta, “Lifting of two-mode states in the D1-D5 CFT,”JHEP01(2024) 183,2309.03321
arXiv 2024
-
[40]
Lifting of superconformal descendants in the D1-D5 CFT,
M. R. R. Hughes, S. D. Mathur, and M. Mehta, “Lifting of superconformal descendants in the D1-D5 CFT,”JHEP04(2024) 129,2311.00052
arXiv 2024
-
[41]
Beyond the tensionless limit: integrability in the symmetric orbifold,
M. R. Gaberdiel, R. Gopakumar, and B. Nairz, “Beyond the tensionless limit: integrability in the symmetric orbifold,”JHEP06(2024) 030,2312.13288
arXiv 2024
-
[42]
Anomalous dimensions in the symmetric orbifold,
M. R. Gaberdiel, F. Lichtner, and B. Nairz, “Anomalous dimensions in the symmetric orbifold,”JHEP05(2025) 084,2411.17612
arXiv 2025
-
[43]
The triplet perturbation of the symmetric orbifold,
M. R. Gaberdiel and I. L. Meur, “The triplet perturbation of the symmetric orbifold,”JHEP03(2026) 231,2509.03132
arXiv 2026
-
[44]
Non-planar corrections in the symmetric orbifold,
M. R. Gaberdiel, B. Nairz, and C. Peng, “Non-planar corrections in the symmetric orbifold,”2605.06465
-
[45]
Bosonization, cocycles, and the D1-D5 CFT on the covering surface,
B. A. Burrington, A. W. Peet, and I. G. Zadeh, “Bosonization, cocycles, and the D1-D5 CFT on the covering surface,”Phys. Rev. D93(2016), no. 2, 026004, 1509.00022
Pith/arXiv arXiv 2016
-
[46]
AdS 3 holography for 1/4 and 1/8 BPS geometries,
S. Giusto, E. Moscato, and R. Russo, “AdS 3 holography for 1/4 and 1/8 BPS geometries,”JHEP11(2015) 004,1507.00945
Pith/arXiv arXiv 2015
-
[47]
Ads 3 holography at dimension two,
S. Giusto, S. Rawash, and D. Turton, “Ads 3 holography at dimension two,”JHEP 07(2019) 171,1904.12880
arXiv 2019
-
[48]
Supercharged AdS 3 Holography,
S. Rawash and D. Turton, “Supercharged AdS 3 Holography,”JHEP07(2021) 178,2105.13046
arXiv 2021
-
[49]
Higher spins in the symmetric orbifold of K3,
M. Baggio, M. R. Gaberdiel, and C. Peng, “Higher spins in the symmetric orbifold of K3,”Phys. Rev. D92(2015) 026007,1504.00926
Pith/arXiv arXiv 2015
-
[50]
Elliptic genera of symmetric products and second quantized strings,
R. Dijkgraaf, G. W. Moore, E. P. Verlinde, and H. L. Verlinde, “Elliptic genera of symmetric products and second quantized strings,”Commun. Math. Phys.185 (1997) 197–209,hep-th/9608096. 29
Pith/arXiv arXiv 1997
-
[51]
Large N Elliptic Genus and AdS/CFT Correspondence,
J. de Boer, “Large N Elliptic Genus and AdS/CFT Correspondence,”JHEP05 (1999) 017,hep-th/9812240
Pith/arXiv arXiv 1999
-
[52]
New supersymmetry index for the D1-D5 conformal field theories,
M. R. R. Hughes and M. Shigemori, “New supersymmetry index for the D1-D5 conformal field theories,”Phys. Rev. D113(2026), no. 4, 046022,2509.19425
arXiv 2026
-
[53]
The Resolved Elliptic Genus and the D1-D5 CFT,
M. R. R. Hughes and M. Shigemori, “The Resolved Elliptic Genus and the D1-D5 CFT,”2603.18138
-
[54]
Quarter BPS operators in N=4 SYM,
A. V. Ryzhov, “Quarter BPS operators in N=4 SYM,”JHEP11(2001) 046, hep-th/0109064
Pith/arXiv arXiv 2001
-
[55]
Three point functions of quarter BPS operators in N=4 SYM,
E. D’Hoker and A. V. Ryzhov, “Three point functions of quarter BPS operators in N=4 SYM,”JHEP02(2002) 047,hep-th/0109065
Pith/arXiv arXiv 2002
-
[56]
Holographic correlators in AdS 3,
S. Giusto, R. Russo, and C. Wen, “Holographic correlators in AdS 3,”JHEP03 (2019) 096,1812.06479
Pith/arXiv arXiv 2019
-
[57]
Holographic correlators with multi-particle states,
N. Ceplak, S. Giusto, M. R. R. Hughes, and R. Russo, “Holographic correlators with multi-particle states,”JHEP09(2021) 204,2105.04670
arXiv 2021
-
[58]
Phases ofN= 2 Sachdev-Ye-Kitaev models,
M. Heydeman, G. J. Turiaci, and W. Zhao, “Phases ofN= 2 Sachdev-Ye-Kitaev models,”JHEP01(2023) 098,2206.14900
arXiv 2023
-
[59]
Towering Gravitons in AdS3/CFT2,
M. R. R. Hughes, K. Jin, D. Matsumoto, L. Miyahara, and M. Shigemori, “Towering Gravitons in AdS3/CFT2,”2604.20663
-
[60]
Holography for people with no time,
H. W. Lin, J. Maldacena, L. Rozenberg, and J. Shan, “Holography for people with no time,”SciPost Phys.14(2023), no. 6, 150,2207.00407
arXiv 2023
-
[61]
Looking at supersymmetric black holes for a very long time,
H. W. Lin, J. Maldacena, L. Rozenberg, and J. Shan, “Looking at supersymmetric black holes for a very long time,”SciPost Phys.14(2023), no. 5, 128,2207.00408
arXiv 2023
-
[62]
Chaos of Berry curvature for BPS microstates,
Y. Chen, S. Colin-Ellerin, O. Mamroud, and K. Papadodimas, “Chaos of Berry curvature for BPS microstates,”2604.23287
-
[63]
Holographic anatomy of fuzzballs,
I. Kanitscheider, K. Skenderis, and M. Taylor, “Holographic anatomy of fuzzballs,” JHEP04(2007) 023,hep-th/0611171
Pith/arXiv arXiv 2007
-
[64]
Secondary invariants and non-perturbative states,
R. de Mello Koch and J. P. Rodrigues, “Secondary invariants and non-perturbative states,”2604.15600. 30
discussion (0)
Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.