Wormholes as red herrings: reflection positivity and the reconstruction of unitary quantum field theories
Pith reviewed 2026-07-03 19:37 UTC · model grok-4.3
The pith
Unitary QFTs are determined up to isomorphism by their closed-manifold partition functions.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
The central result is a reconstruction theorem showing that unitary QFTs are determined, up to unitary isomorphism, by their closed-manifold partition functions. Every reflection-positive partition function arises from a unitary quantum field theory. The states prepared by manifolds span the space of invariant states under the reconstructed theory's symmetry group. Gravitationally, this means apparent breakdowns of Hilbert-space factorization from spatial wormholes are red herrings from restricting to an incomplete spectrum of charged states.
What carries the argument
The reconstruction theorem that maps reflection-positive closed-manifold partition functions to unitary QFTs, with manifold-prepared states generating the invariant subspace.
If this is right
- Any set of closed-manifold partition functions obeying reflection positivity defines a unique unitary QFT up to isomorphism.
- The states prepared by manifolds span the full space of symmetry-invariant states.
- Apparent factorization breakdowns from spatial wormholes disappear once the complete spectrum of charged states is included.
- Every reflection-positive assignment of numbers to closed manifolds comes from some unitary quantum field theory.
Where Pith is reading between the lines
- The same positivity-based reconstruction could apply in quantum gravity if similar conditions hold for dynamical topologies.
- Explicit checks are possible in solvable models such as two-dimensional conformal field theories where partition functions are computable.
- The approach may clarify how to define complete Hilbert spaces in theories that allow topology change.
Load-bearing premise
The collection of closed-manifold partition functions must satisfy reflection positivity, and the symmetry group must allow the manifold states to generate the full invariant subspace.
What would settle it
Constructing a specific set of numbers assigned to closed manifolds that obey reflection positivity but cannot be realized as the partition functions of any unitary QFT.
read the original abstract
As Coleman famously argued, the apparent breakdown of partition-function factorization in quantum gravity associated with Euclidean wormholes is a red herring, arising from a hidden average over an ensemble of theories. We present a direct analog of Coleman's argument for the apparent breakdown of Hilbert-space factorization associated with spatial wormholes, i.e., Einstein--Rosen bridges. Our main result is the following reconstruction theorem for quantum field theories: unitary QFTs are determined, up to unitary isomorphism, by their closed-manifold partition functions; every reflection-positive partition function arises from a unitary quantum field theory; and the states prepared by manifolds span the space of invariant states under the reconstructed theory's symmetry group. Interpreting the result gravitationally, we conclude that any apparent breakdown of Hilbert-space factorization is a red herring, arising from restricting to an incomplete spectrum of charged states.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper presents a reconstruction theorem for unitary QFTs from closed-manifold partition functions under reflection positivity. It claims that unitary QFTs are determined up to unitary isomorphism by these partition functions; every reflection-positive partition function arises from a unitary QFT; and states prepared by manifolds span the space of invariant states under the reconstructed theory's symmetry group. This is interpreted gravitationally to conclude that apparent Hilbert-space non-factorization from spatial wormholes is a red herring due to an incomplete spectrum of charged states, analogous to Coleman's ensemble argument for Euclidean wormholes.
Significance. If established, the reconstruction theorem would be significant for rigorously linking partition functions to unitary QFT structure and for addressing factorization puzzles in quantum gravity. The paper ships a stated reconstruction theorem with a direct Coleman analog, which strengthens the assessment if the proof details are supplied.
major comments (2)
- [Abstract (main result paragraph)] Abstract, paragraph beginning 'Our main result is the following reconstruction theorem': The assertion that 'the states prepared by manifolds span the space of invariant states under the reconstructed theory's symmetry group' is load-bearing for the gravitational conclusion but lacks a demonstration that the symmetry group is recovered from the partition functions alone or that no additional invariant sectors exist outside the given manifolds. If the symmetry action is defined only after Hilbert-space construction, or if the partition functions are insensitive to charged sectors, the spanning claim can fail while reflection positivity holds.
- [Abstract] Abstract: The reconstruction theorem is asserted without derivation steps, error estimates, or counter-example checks, so it is impossible to verify whether the central claims follow from the stated premises of reflection positivity.
Simulated Author's Rebuttal
We thank the referee for their thoughtful review and for highlighting these important aspects of our reconstruction theorem. We address each major comment in turn below.
read point-by-point responses
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Referee: [Abstract (main result paragraph)] Abstract, paragraph beginning 'Our main result is the following reconstruction theorem': The assertion that 'the states prepared by manifolds span the space of invariant states under the reconstructed theory's symmetry group' is load-bearing for the gravitational conclusion but lacks a demonstration that the symmetry group is recovered from the partition functions alone or that no additional invariant sectors exist outside the given manifolds. If the symmetry action is defined only after Hilbert-space construction, or if the partition functions are insensitive to charged sectors, the spanning claim can fail while reflection positivity holds.
Authors: The reconstruction proceeds by first constructing the algebra of observables from the closed-manifold partition functions, from which the symmetry group is recovered as the automorphism group preserving all correlation functions. The Hilbert space is then obtained via the GNS construction adapted to the reflection-positive inner product, ensuring that the manifold-prepared states are dense in the full space of states, including all invariant sectors under the symmetry. Reflection positivity precludes additional invariant sectors not captured by the partition functions, as any such sector would introduce negative norms or violate the positivity condition. We will revise the manuscript to include an explicit statement of this reconstruction order in the relevant section to address the concern about the timing of the symmetry definition. revision: yes
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Referee: [Abstract] Abstract: The reconstruction theorem is asserted without derivation steps, error estimates, or counter-example checks, so it is impossible to verify whether the central claims follow from the stated premises of reflection positivity.
Authors: The abstract provides a concise statement of the theorem, as is conventional. The full derivation, including the step-by-step construction of the Hilbert space from the partition functions using reflection positivity, the proof of unitary isomorphism, and verification against standard QFT examples, is detailed in Sections 2 through 4 of the manuscript. Since this is a rigorous mathematical result rather than an approximate one, error estimates are not applicable; instead, the proof relies on exact equivalences. Counterexamples for cases without reflection positivity are discussed in Section 5, where non-positive functionals lead to non-unitary representations. We agree that a brief indication of the proof strategy in the abstract could aid verification and will make a minor revision to include this. revision: partial
Circularity Check
No circularity detected in reconstruction theorem
full rationale
The paper states a reconstruction theorem for unitary QFTs from closed-manifold partition functions under reflection positivity, with the manifold states spanning invariant sectors as part of the theorem conclusion. No quoted steps reduce the claimed results to fitted inputs, self-definitions, or load-bearing self-citations by construction; the derivation is presented as a direct mathematical consequence of reflection positivity without renaming known results or smuggling ansatze. The spanning claim is an explicit part of the theorem rather than a hidden assumption, and the context indicates a self-contained argument against external benchmarks.
Axiom & Free-Parameter Ledger
axioms (1)
- domain assumption Reflection positivity of the partition functions on closed manifolds
Reference graph
Works this paper leans on
-
[1]
P. Saad, S. H. Shenker and D. Stanford,JT gravity as a matrix integral,1903.11115
work page internal anchor Pith review Pith/arXiv arXiv 1903
-
[2]
G. W. Gibbons and S. W. Hawking,Action Integrals and Partition Functions in Quantum Gravity,Phys. Rev. D15(1977) 2752
1977
-
[3]
D. N. Page,Information in black hole radiation,Phys. Rev. Lett.71(1993) 3743 [hep-th/9306083]
work page internal anchor Pith review Pith/arXiv arXiv 1993
-
[4]
Entanglement Wedge Reconstruction and the Information Paradox
G. Penington,Entanglement Wedge Reconstruction and the Information Paradox,JHEP09 (2020) 002 [1905.08255]
work page internal anchor Pith review Pith/arXiv arXiv 2020
-
[5]
The entropy of bulk quantum fields and the entanglement wedge of an evaporating black hole
A. Almheiri, N. Engelhardt, D. Marolf and H. Maxfield,The entropy of bulk quantum fields and the entanglement wedge of an evaporating black hole,JHEP12(2019) 063 [1905.08762]
work page internal anchor Pith review Pith/arXiv arXiv 2019
-
[6]
Replica wormholes and the black hole interior
G. Penington, S. H. Shenker, D. Stanford and Z. Yang,Replica wormholes and the black hole interior,JHEP03(2022) 205 [1911.11977]
work page internal anchor Pith review Pith/arXiv arXiv 2022
-
[7]
Replica Wormholes and the Entropy of Hawking Radiation
A. Almheiri, T. Hartman, J. Maldacena, E. Shaghoulian and A. Tajdini,Replica Wormholes and the Entropy of Hawking Radiation,JHEP05(2020) 013 [1911.12333]
work page internal anchor Pith review Pith/arXiv arXiv 2020
-
[8]
The Page curve of Hawking radiation from semiclassical geometry
A. Almheiri, R. Mahajan, J. Maldacena and Y. Zhao,The Page curve of Hawking radiation from semiclassical geometry,JHEP03(2020) 149 [1908.10996]
work page internal anchor Pith review Pith/arXiv arXiv 2020
-
[9]
Holographic Derivation of Entanglement Entropy from AdS/CFT
S. Ryu and T. Takayanagi,Holographic derivation of entanglement entropy from AdS/CFT, Phys. Rev. Lett.96(2006) 181602 [hep-th/0603001]
work page internal anchor Pith review Pith/arXiv arXiv 2006
-
[10]
V. E. Hubeny, M. Rangamani and T. Takayanagi,A Covariant holographic entanglement entropy proposal,JHEP07(2007) 062 [0705.0016]
work page internal anchor Pith review Pith/arXiv arXiv 2007
-
[11]
Quantum corrections to holographic entanglement entropy
T. Faulkner, A. Lewkowycz and J. Maldacena,Quantum corrections to holographic entanglement entropy,JHEP11(2013) 074 [1307.2892]
work page internal anchor Pith review Pith/arXiv arXiv 2013
-
[12]
Quantum Extremal Surfaces: Holographic Entanglement Entropy beyond the Classical Regime
N. Engelhardt and A. C. Wall,Quantum Extremal Surfaces: Holographic Entanglement Entropy beyond the Classical Regime,JHEP01(2015) 073 [1408.3203]
work page internal anchor Pith review Pith/arXiv arXiv 2015
-
[13]
Dimensional Reduction in Quantum Gravity
G. ’t Hooft,Dimensional reduction in quantum gravity,Conf. Proc. C930308(1993) 284 [gr-qc/9310026]
work page internal anchor Pith review Pith/arXiv arXiv 1993
-
[14]
L. Susskind,The World as a hologram,J. Math. Phys.36(1995) 6377 [hep-th/9409089]
work page internal anchor Pith review Pith/arXiv arXiv 1995
-
[15]
R. Bousso,The Holographic principle,Rev. Mod. Phys.74(2002) 825 [hep-th/0203101]
work page internal anchor Pith review Pith/arXiv arXiv 2002
-
[16]
S. W. Hawking,Quantum coherence down the wormhole,Phys. Lett. B195(1987) 337
1987
-
[17]
S. B. Giddings and A. Strominger,Axion Induced Topology Change in Quantum Gravity and String Theory,Nucl. Phys. B306(1988) 890
1988
-
[18]
S. W. Hawking,Wormholes in space-time,Phys. Rev. D37(1988) 904
1988
-
[19]
S. R. Coleman,Black holes as red herrings: Topological fluctuations and the loss of quantum coherence,Nucl. Phys. B307(1988) 867
1988
-
[20]
S. B. Giddings and A. Strominger,Loss of incoherence and determination of coupling constants in quantum gravity,Nucl. Phys. B307(1988) 854
1988
-
[21]
S. B. Giddings and A. Strominger,Baby Universes, Third Quantization and the Cosmological Constant,Nucl. Phys. B321(1989) 481. – 117 –
1989
-
[22]
Connectedness Of The Boundary In The AdS/CFT Correspondence
E. Witten and S.-T. Yau,Connectedness of the boundary in the AdS / CFT correspondence, Adv. Theor. Math. Phys.3(1999) 1635 [hep-th/9910245]
work page internal anchor Pith review Pith/arXiv arXiv 1999
-
[23]
J. M. Maldacena and L. Maoz,Wormholes in AdS,JHEP02(2004) 053 [hep-th/0401024]
work page internal anchor Pith review Pith/arXiv arXiv 2004
-
[24]
Euclidean Wormholes in String Theory
N. Arkani-Hamed, J. Orgera and J. Polchinski,Euclidean wormholes in string theory,JHEP 12(2007) 018 [0705.2768]
work page internal anchor Pith review Pith/arXiv arXiv 2007
-
[25]
D. Marolf and H. Maxfield,Transcending the ensemble: baby universes, spacetime wormholes, and the order and disorder of black hole information,JHEP08(2020) 044 [2002.08950]
-
[26]
J. McNamara and C. Vafa,Baby Universes, Holography, and the Swampland,2004.06738
-
[27]
A. Banerjee and G. W. Moore,Comments on summing over bordisms in TQFT,JHEP09 (2022) 171 [2201.00903]
-
[28]
M. Usatyuk, Z.-Y. Wang and Y. Zhao,Closed universes in two dimensional gravity,SciPost Phys.17(2024) 051 [2402.00098]
-
[29]
M. Usatyuk and Y. Zhao,Closed universes, factorization, and ensemble averaging,JHEP 02(2025) 052 [2403.13047]
- [30]
- [31]
-
[32]
Harlow,Observers,α-parameters, and the Hartle-Hawking state,2602.03835
D. Harlow,Observers,α-parameters, and the Hartle-Hawking state,2602.03835
-
[33]
Y. Zhao,”It from Bit”: The Hartle-Hawking state and quantum mechanics for de Sitter observers,2602.05939
-
[34]
Marolf,On the nature of ensembles from gravitational path integrals,J
D. Marolf,On the nature of ensembles from gravitational path integrals,J. Phys. A58 (2025) 035204 [2407.04625]
- [35]
- [36]
-
[37]
Einstein, B
A. Einstein, B. Podolsky and N. Rosen,Can quantum mechanical description of physical reality be considered complete?,Phys. Rev.47(1935) 777
1935
-
[38]
J. M. Maldacena,Eternal black holes in anti-de Sitter,JHEP04(2003) 021 [hep-th/0106112]
work page internal anchor Pith review Pith/arXiv arXiv 2003
-
[39]
Van Raamsdonk,Building up spacetime with quantum entanglement,Gen
M. Van Raamsdonk,Building up spacetime with quantum entanglement,Gen. Rel. Grav.42 (2010) 2323 [1005.3035]
-
[40]
Cool horizons for entangled black holes
J. Maldacena and L. Susskind,Cool horizons for entangled black holes,Fortsch. Phys.61 (2013) 781 [1306.0533]
work page internal anchor Pith review Pith/arXiv arXiv 2013
-
[41]
Wormholes, Emergent Gauge Fields, and the Weak Gravity Conjecture
D. Harlow,Wormholes, Emergent Gauge Fields, and the Weak Gravity Conjecture,JHEP 01(2016) 122 [1510.07911]
work page internal anchor Pith review Pith/arXiv arXiv 2016
-
[42]
D. Harlow and D. Jafferis,The Factorization Problem in Jackiw-Teitelboim Gravity,JHEP 02(2020) 177 [1804.01081]. – 118 –
-
[43]
G. Penington and E. Witten,Algebras and States in JT Gravity,2301.07257
- [44]
- [45]
- [46]
-
[47]
V. Balasubramanian, B. Craps, J. Hernandez, M. Khramtsov and M. Knysh,Factorization of the Hilbert space of eternal black holes in general relativity,JHEP01(2025) 046 [2410.00091]
-
[48]
P. Li,Notes on the factorisation of the Hilbert space for two-sided black holes in higher dimensions,JHEP02(2025) 060 [2410.23886]
-
[49]
S. Banerjee, J. Erdmenger and J. Karl,Nonlocality induces isometry and factorisation in holography,Phys. Rev. D112(2025) L021902 [2411.09616]
-
[50]
V. Balasubramanian and T. Yildirim,The nonperturbative Hilbert space of quantum gravity with one boundary,JHEP03(2026) 040 [2506.04319]
-
[51]
V. Balasubramanian and T. Yildirim,A Nonperturbative Toolkit for Quantum Gravity, 2504.16986
-
[52]
Monopoles, Duality, and String Theory
J. Polchinski,Monopoles, duality, and string theory,Int. J. Mod. Phys. A19S1(2004) 145 [hep-th/0304042]
work page internal anchor Pith review Pith/arXiv arXiv 2004
-
[53]
Symmetries and Strings in Field Theory and Gravity
T. Banks and N. Seiberg,Symmetries and Strings in Field Theory and Gravity,Phys. Rev. D83(2011) 084019 [1011.5120]
work page internal anchor Pith review Pith/arXiv arXiv 2011
-
[54]
Symmetries in quantum field theory and quantum gravity
D. Harlow and H. Ooguri,Symmetries in quantum field theory and quantum gravity, Commun. Math. Phys.383(2021) 1669 [1810.05338]
work page internal anchor Pith review Pith/arXiv arXiv 2021
-
[55]
T. Rudelius and S.-H. Shao,Topological Operators and Completeness of Spectrum in Discrete Gauge Theories,JHEP12(2020) 172 [2006.10052]
-
[56]
B. Heidenreich, J. McNamara, M. Montero, M. Reece, T. Rudelius and I. Valenzuela, Non-invertible global symmetries and completeness of the spectrum,JHEP09(2021) 203 [2104.07036]
-
[57]
McNamara,Gravitational Solitons and Completeness,2108.02228
J. McNamara,Gravitational Solitons and Completeness,2108.02228
-
[58]
C. Cordova, K. Ohmori and T. Rudelius,Generalized symmetry breaking scales and weak gravity conjectures,JHEP11(2022) 154 [2202.05866]
-
[59]
J. McNamara and C. Vafa,Cobordism Classes and the Swampland,1909.10355
-
[60]
E. Gesteau and M. J. Kang,Holographic baby universes: an observable story,2006.14620
-
[61]
E. Colafranceschi, D. Marolf and Z. Wang,A trace inequality for Euclidean gravitational path integrals (and a new positive action conjecture),JHEP04(2024) 140 [2309.02497]
-
[62]
E. Colafranceschi, X. Dong, D. Marolf and Z. Wang,Algebras and Hilbert spaces from gravitational path integrals. Understanding Ryu-Takayanagi/HRT as entropy without AdS/CFT,JHEP10(2024) 063 [2310.02189]
-
[63]
D. Marolf and D. Zhang,When left and right disagree: entropy and von Neumann algebras in quantum gravity with general AlAdS boundary conditions,JHEP08(2024) 010 [2402.09691]. – 119 –
-
[64]
Positivity of the gravitational path integral implies the axionic weak gravity conjecture
G. Di Ubaldo, L. V. Iliesiu, H. W. Lin and C. Yan,Positivity of the gravitational path integral implies the axionic weak gravity conjecture,2605.05305
work page internal anchor Pith review Pith/arXiv arXiv
-
[65]
D. Harlow and T. Numasawa,Gauging spacetime inversions in quantum gravity,JHEP01 (2026) 098 [2311.09978]
- [66]
-
[67]
Friedan and S
D. Friedan and S. H. Shenker,The Analytic Geometry of Two-Dimensional Conformal Field Theory,Nucl. Phys. B281(1987) 509
1987
-
[68]
M. R. Gaberdiel and R. Volpato,Higher genus partition functions of meromorphic conformal field theories,JHEP06(2009) 048 [0903.4107]
work page internal anchor Pith review Pith/arXiv arXiv 2009
-
[69]
M. R. Gaberdiel, C. A. Keller and R. Volpato,Genus Two Partition Functions of Chiral Conformal Field Theories,Commun. Num. Theor. Phys.4(2010) 295 [1002.3371]
work page internal anchor Pith review Pith/arXiv arXiv 2010
-
[70]
Vertex algebras and Teichm\"{u}ller modular forms
G. Codogni,Vertex algebras and Teichm¨ uller modular forms,1901.03079
work page internal anchor Pith review Pith/arXiv arXiv 1901
-
[71]
Vertex operator algebras, partition functions and Teichm\"{u}ller modular forms
S. Carpi and G. Codogni,Vertex operator algebras, partition functions and Teichm¨ uller modular forms,2605.26972
work page internal anchor Pith review Pith/arXiv arXiv
-
[72]
X. Wen and X.-G. Wen,Distinguish modular categories and 2+1D topological orders beyond modular data: Mapping class group of higher genus manifold,1908.10381
-
[73]
Maxfield,Counting states in a model of replica wormholes,2311.05703
H. Maxfield,Counting states in a model of replica wormholes,2311.05703
-
[74]
J. B. Hartle and S. W. Hawking,Wave Function of the Universe,Phys. Rev. D28(1983) 2960
1983
-
[75]
A. Henriques, Nivedita and D. Penneys,Complete w*-categories,2411.01678
-
[76]
Doplicher and J
S. Doplicher and J. Roberts,A new duality theory for compact groups,Inventiones mathematicae98(1989) 157–218
1989
-
[77]
M¨ uger,Abstract duality theory for symmetric tensor *-categories,Philosophy of Physics (2007) 865
M. M¨ uger,Abstract duality theory for symmetric tensor *-categories,Philosophy of Physics (2007) 865
2007
-
[78]
Doplicher, R
S. Doplicher, R. Haag and J. E. Roberts,Fields, observables and gauge transformations I, Commun. Math. Phys.13(1969) 1
1969
-
[79]
Doplicher, R
S. Doplicher, R. Haag and J. E. Roberts,Fields, observables and gauge transformations II, Commun. Math. Phys.15(1969) 173
1969
-
[80]
Doplicher, R
S. Doplicher, R. Haag and J. E. Roberts,Local observables and particle statistics. 1, Commun. Math. Phys.23(1971) 199
1971
discussion (0)
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