Wormhole Nucleation via Topological Surgery in Lorentzian Geometry
Pith reviewed 2026-05-22 16:57 UTC · model grok-4.3
The pith
A wormhole can be created without singularities in classical general relativity by using 0-surgery and replacing the critical point with closed timelike curves via connected sum with CP².
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
Using techniques from topological surgery and Morse theory, a 0-surgery process is applied to describe the neighborhood of the nucleation point, yielding a singular Lorentzian cobordism. The Misner trick of taking a connected sum with CP² produces an everywhere nondegenerate Lorentzian metric that replaces the naked singularity at the Morse critical point with a region containing closed timelike curves. The obtained spacetime is nonsingular but violates all the standard energy conditions, showing that a wormhole can be created without singularities in classical general relativity.
What carries the argument
The 0-surgery on a 3-manifold embedded in 4-dimensional Lorentzian spacetime, resolved by the Misner connected-sum construction with CP² to eliminate the Morse critical-point degeneracy.
If this is right
- A wormhole connecting regions of different topology can form inside a compact region of spacetime without any singularity.
- The spacetime must violate all standard energy conditions.
- Closed timelike curves appear in the finite region that replaces the former Morse critical point.
- Topological surgery can be carried out on Lorentzian cobordisms while preserving nondegeneracy of the metric.
- Wormhole nucleation occurs through a process that changes the topology of spatial slices.
Where Pith is reading between the lines
- If the same replacement trick works for other Morse critical points, many additional topological transitions in spacetime might be realizable without singularities.
- The unavoidable appearance of closed timelike curves near the nucleation site suggests that causality violation is a built-in feature of this classical construction.
- Similar surgery-plus-connected-sum methods could be applied to other 4-manifolds or to non-compact spacetimes to generate further exotic geometries.
- The construction raises the possibility that wormhole formation in classical gravity is always accompanied by regions where time travel becomes locally possible.
Load-bearing premise
The connected sum with CP² produces an everywhere nondegenerate Lorentzian metric that replaces the naked singularity without introducing new singularities or other pathologies.
What would settle it
An explicit local computation of the metric after the connected sum that finds even one point where the metric becomes degenerate or curvature becomes unbounded would falsify the nondegeneracy claim.
Figures
read the original abstract
We construct a model for the nucleation of a wormhole within a Lorentzian spacetime by employing techniques from topological surgery and Morse theory. In our framework, a 0-surgery process describes the neighborhood of the nucleation point inside a compact region of spacetime, yielding a singular Lorentzian cobordism that connects two spacelike regions with different topologies. To avoid the singularity at the critical point of the Morse function, we employ the Misner trick of taking a connected sum with a closed 4-manifold -- namely $\mathbb{CP}^{2}$ -- to obtain an everywhere nondegenerate Lorentzian metric. This connected sum replaces the naked singularity with a region containing closed timelike curves. The obtained spacetime is nonsingular, but violates all the standard energy conditions. Our construction, thus, shows that a wormhole can be "created" without singularities in classical general relativity.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The manuscript constructs a model for wormhole nucleation in Lorentzian geometry by applying 0-surgery to create a singular cobordism between spacelike regions of different topologies, then uses a connected sum with CP² via the Misner trick to eliminate the Morse critical point singularity, replacing it with a region of closed timelike curves while violating energy conditions. The central claim is that this yields a nonsingular spacetime in which a wormhole is created within classical general relativity.
Significance. If the metric construction is rigorously verified, this work offers an interesting topological approach to modeling wormhole formation without curvature singularities, highlighting the trade-off with causality violations and energy condition breaches. It builds on established tools like Morse theory and connected sums but applies them in a Lorentzian setting, potentially stimulating further research on exotic spacetimes. The direct construction from topological surgery is a strength, though the lack of explicit verification of the resulting metric reduces immediate applicability.
major comments (1)
- [Abstract (resolution step via connected sum with CP²)] The central claim that the Misner connected-sum operation with CP² produces an everywhere nondegenerate Lorentzian metric (replacing the Morse critical-point degeneracy with CTCs) is load-bearing but unsupported by explicit local analysis. No coordinate chart or metric form is supplied near the S³ gluing locus to verify preservation of the (1,3) signature, consistent extension of the time-orientation, or global nondegeneracy after excising a 4-ball from CP² (whose Euler characteristic precludes a Lorentzian metric). This must be addressed to substantiate the nonsingularity assertion.
minor comments (2)
- [Construction section] The description of the 0-surgery process would benefit from an explicit diagram or local coordinate patches illustrating the transition between the two spacelike regions.
- [Introduction] Additional references to prior applications of the Misner trick or topological surgery in Lorentzian GR would help situate the novelty of the approach.
Simulated Author's Rebuttal
We thank the referee for their careful and constructive report. The central concern regarding explicit verification of the Lorentzian metric after the connected-sum operation is well-taken, and we address it directly below while indicating the revisions we will make.
read point-by-point responses
-
Referee: [Abstract (resolution step via connected sum with CP²)] The central claim that the Misner connected-sum operation with CP² produces an everywhere nondegenerate Lorentzian metric (replacing the Morse critical-point degeneracy with CTCs) is load-bearing but unsupported by explicit local analysis. No coordinate chart or metric form is supplied near the S³ gluing locus to verify preservation of the (1,3) signature, consistent extension of the time-orientation, or global nondegeneracy after excising a 4-ball from CP² (whose Euler characteristic precludes a Lorentzian metric). This must be addressed to substantiate the nonsingularity assertion.
Authors: We agree that the absence of an explicit local coordinate description near the gluing locus leaves the nondegeneracy claim insufficiently substantiated in the current draft. The Misner construction proceeds by excising a 4-ball from the singular cobordism and from CP², then identifying the resulting S³ boundaries. In a neighborhood of this S³ we adopt Fermi normal coordinates along the gluing hypersurface, on which the metric takes the form ds² = −dt² + dr² + r² dΩ₂² plus a small perturbation that introduces the CTCs contributed by the CP² summand; the (1,3) signature is manifest and the time-orientation extends continuously across the interface because the normal to the S³ is spacelike on both sides. Because the final object is a cobordism (a manifold with two spacelike boundary components) rather than a closed 4-manifold, the Euler-characteristic obstruction that precludes a Lorentzian metric on closed CP² does not apply; a nowhere-vanishing timelike vector field can be chosen on the interior that matches the standard time-orientation on the original cobordism and remains non-vanishing after the sum. We will add a new subsection containing these local coordinates, the explicit metric ansatz, and a verification that the resulting tensor is nondegenerate and time-orientable everywhere. This constitutes a major but straightforward revision. revision: yes
Circularity Check
Direct construction from established topological surgery and Misner trick; no reduction to self-inputs
full rationale
The paper advances a explicit construction: a 0-surgery on a Lorentzian cobordism produces a singular Morse critical point, which is then replaced by a connected sum with CP² (after excising a 4-ball) to yield a nondegenerate metric containing CTCs. This step is asserted via the known Misner trick and standard results in 4-manifold topology; it does not define the final metric or the absence of singularities in terms of any quantity fitted or derived inside the paper itself. No equations equate a 'prediction' to an input parameter, and no load-bearing premise rests solely on an unverified self-citation chain. The derivation remains self-contained against external topological benchmarks.
Axiom & Free-Parameter Ledger
axioms (2)
- domain assumption Morse theory can be applied to a Lorentzian metric to locate and classify the critical point of the nucleation process.
- domain assumption 0-surgery on a spacelike hypersurface produces a valid cobordism between regions of differing topology in Lorentzian geometry.
invented entities (1)
-
Closed-timelike-curve region created by connected sum with CP²
no independent evidence
Lean theorems connected to this paper
-
IndisputableMonolith/Foundation/AlexanderDuality.leanalexander_duality_circle_linking echoes?
echoesECHOES: this paper passage has the same mathematical shape or conceptual pattern as the Recognition theorem, but is not a direct formal dependency.
To avoid the singularity at the critical point of the Morse function, we employ the Misner trick of taking a connected sum with a closed 4-manifold—namely CP²—to obtain an everywhere nondegenerate Lorentzian metric. This connected sum replaces the naked singularity with a region containing closed timelike curves.
What do these tags mean?
- matches
- The paper's claim is directly supported by a theorem in the formal canon.
- supports
- The theorem supports part of the paper's argument, but the paper may add assumptions or extra steps.
- extends
- The paper goes beyond the formal theorem; the theorem is a base layer rather than the whole result.
- uses
- The paper appears to rely on the theorem as machinery.
- contradicts
- The paper's claim conflicts with a theorem or certificate in the canon.
- unclear
- Pith found a possible connection, but the passage is too broad, indirect, or ambiguous to say the theorem truly supports the claim.
Reference graph
Works this paper leans on
-
[1]
˙t2 0 + ˙ρ2 0 =−2 √ 26. Taking the positive time direction, ˙t0 = 1, gives ˙ρ0 = ±1, representing geodesics either entering the wormhole or escaping to infinity. Because we are interested in the incoming case, we choose ˙ρ0 = −1; the numerical result is plotted in Fig. 7. A similar procedure applies to lightlike geodesics, with ϵ = 0. With the same initia...
-
[2]
˙t2 0 + ˙ρ2 0 = 0 selects ˙ρ0 = −( p 1 + 2 √ 26)/2, and the resulting trajec- tory is also plotted in Fig. 7. Before briefly discussing violations of the energy condi- tions for this dynamical wormhole, we want to identify, in a more rigorous way, the fundamental properties of the wormhole. These properties should be intrinsic and insensitive to the globa...
work page 2024
-
[3]
J. A. Wheeler, Geons, Phys. Rev.97, 511 (1955)
work page 1955
-
[4]
C. W. Misner and J. A. Wheeler, Classical physics as geometry, Annals of Physics2, 525 (1957)
work page 1957
-
[5]
M. Visser,Lorentzian Wormholes: From Einstein to Hawking(American Institute of Physics Melville, NY, 1996)
work page 1996
-
[6]
F. S. N. Lobo, ed.,Wormholes, Warp Drives and Energy Conditions(Springer Cham, 2017)
work page 2017
-
[7]
Shoshany, Lectures on Faster-Than-Light Travel and Time Travel, SciPost Phys
B. Shoshany, Lectures on Faster-Than-Light Travel and Time Travel, SciPost Phys. Lect. Notes , 10 (2019), arXiv:1907.04178
-
[8]
Hawking, Spacetime foam, Nuclear Physics B144, 349 (1978)
S. Hawking, Spacetime foam, Nuclear Physics B144, 349 (1978)
work page 1978
-
[9]
R. P. Geroch, Topology in General Relativity, Journal of Mathematical Physics8, 782 (2004)
work page 2004
-
[10]
G. T. Horowitz, Topology change in general relativity (1991), arXiv:hep-th/9109030 [hep-th]
work page internal anchor Pith review Pith/arXiv arXiv 1991
-
[11]
G. T. Horowitz, Topology change in classical and quantum gravity, Classical and Quantum Gravity8, 587 (1991)
work page 1991
-
[12]
J. Louko and R. D. Sorkin, Complex actions in two- dimensional topology change, Classical and Quantum Gravity14, 179 (1997)
work page 1997
-
[13]
H. F. Dowker, R. S. Garcia, and S. Surya, Morse index and causal continuity. a criterion for topology change in quantum gravity, Classical and Quantum Gravity17, 697 (2000)
work page 2000
-
[14]
Topology change in quantum gravity
F. Dowker, Topology change in quantum gravity (2002), arXiv:gr-qc/0206020 [gr-qc]
work page internal anchor Pith review Pith/arXiv arXiv 2002
-
[15]
K. Sato, M. Sasaki, H. Kodama, and K.-i. Maeda, Cre- ation of Wormholes by First Order Phase Transition of a Vacuum in the Early Universe, Progress of Theoretical Physics65, 1443 (1981)
work page 1981
-
[16]
A. Hosoya and W. Ogura, Wormhole instanton solution in the einstein-yang-mills system, Physics Letters B225, 117 (1989)
work page 1989
-
[17]
Rey, Space-time wormholes with yang-mills fields, Nuclear Physics B336, 146 (1990)
S.-J. Rey, Space-time wormholes with yang-mills fields, Nuclear Physics B336, 146 (1990)
work page 1990
- [18]
-
[19]
L. Battarra, G. Lavrelashvili, and J.-L. Lehners, Creation of wormholes by quantum tunnelling in modified gravity theories, Phys. Rev. D90, 124015 (2014)
work page 2014
-
[20]
Wormhole creation by quantum tunnelling
L. Battarra, G. Lavrelashvili, and J.-L. Lehners, Worm- hole creation by quantum tunnelling, arXiv e-prints , arXiv:1603.08728 (2016), arXiv:1603.08728 [gr-qc]
work page internal anchor Pith review Pith/arXiv arXiv 2016
-
[21]
A. Borde, How impossible is topology change?, Bulletin of the Astronomical Society of India25, 571 (1997). 23
work page 1997
-
[22]
Topology Change in Classical General Relativity
A. Borde, Topology change in classical general relativity (1994), arXiv:gr-qc/9406053 [gr-qc]
work page internal anchor Pith review Pith/arXiv arXiv 1994
-
[23]
J. Hauser and B. Shoshany, Time Travel Paradoxes and Multiple Histories, Phys. Rev. D102, 064062 (2020), arXiv:1911.11590
-
[24]
B. Shoshany and J. Wogan, Wormhole Time Machines and Multiple Histories, Gen. Relativ. Gravit.55, 44 (2023), arXiv:2110.02448
-
[25]
B. Shoshany and Z. Stober, Time Travel Paradoxes and Entangled Timelines (2023), arXiv:2303.07635
-
[26]
M. S. Morris, K. S. Thorne, and U. Yurtsever, Wormholes, time machines, and the weak energy condition, Phys. Rev. Lett.61, 1446 (1988)
work page 1988
-
[27]
B. Shoshany and B. Snodgrass, Warp Drives and Closed Timelike Curves, Classical and Quantum Gravity41, 205005 (2024), arXiv:2309.10072
-
[28]
Topological surgery in cosmic phenomena
S. Antoniou, L. H. Kauffman, and S. Lambropoulou, Topological surgery in cosmic phenomena (2018), arXiv:1812.00837 [math.GT]
work page internal anchor Pith review Pith/arXiv arXiv 2018
-
[29]
B. L. Reinhart, Cobordism and the euler number, Topol- ogy2, 173 (1963)
work page 1963
-
[30]
M. Y. Konstantinov, Some problems of topology change description in the theory of spacetime, International Jour- nal of Modern Physics D07, 1 (1998)
work page 1998
-
[31]
M. Y. Konstantinov and V. N. Melnikov, Topological tran- sitions in the theory of spacetime, Classical and Quantum Gravity3, 401 (1986)
work page 1986
-
[32]
H. F. Dowker and R. S. Garcia, A handlebody calculus for topology change, Classical and Quantum Gravity15, 1859 (1998)
work page 1998
-
[33]
Yodzis, Lorentz cobordism, Communications in Math- ematical Physics26, 39 (1972)
P. Yodzis, Lorentz cobordism, Communications in Math- ematical Physics26, 39 (1972)
work page 1972
-
[34]
S. W. Hawking, Chronology protection conjecture, Phys. Rev. D46, 603 (1992)
work page 1992
-
[35]
D. Finkelstein and C. W. Misner, Some new conservation laws, Annals of Physics6, 230 (1959)
work page 1959
-
[36]
D. Finkelstein and G. McCollum, Kinks and extensions, Journal of Mathematical Physics16, 2250 (2008)
work page 2008
-
[37]
G. W. Gibbons and S. W. Hawking, Selection rules for topology change, Communications in Mathematical Physics148, 345 (1992)
work page 1992
-
[38]
G. W. Gibbons, Topology and topology change in general relativity, Classical and Quantum Gravity10, S75 (1993)
work page 1993
-
[39]
G. W. Gibbons, Topology change in classical and quantum gravity (2011), arXiv:1110.0611 [gr-qc]
work page internal anchor Pith review Pith/arXiv arXiv 2011
-
[40]
A. Anderson and B. DeWitt, Does the topology of space fluctuate?, Foundations of Physics16, 91 (1986)
work page 1986
-
[41]
B. S. Kay, M. J. Radzikowski, and R. M. Wald, Quantum field theory on spacetimes with a compactly generated cauchy horizon, Communications in Mathematical Physics 183, 533 (1997)
work page 1997
-
[42]
J. R. Gott and L.-X. Li, Can the universe create itself?, Phys. Rev. D58, 023501 (1998)
work page 1998
-
[43]
OGRe: An Object-Oriented General Relativity Package for Mathematica
B. Shoshany, OGRe: An Object-Oriented General Rela- tivity Package for Mathematica, Journal of Open Source Software6, 3416 (2021), arXiv:2109.04193
-
[44]
B. Shoshany, OGRePy: An Object-Oriented General Rel- ativity Package for Python, Journal of Open Research Software13, 9 (2025), arXiv:2409.03803
-
[45]
S. Antoniou, L. H. Kauffman, and S. Lambropoulou, Topo- logical surgery in the small and in the large, inKnots, Low-Dimensional Topology and Applications, edited by C. C. Adams, C. M. Gordon, V. F. Jones, L. H. Kauff- man, S. Lambropoulou, K. C. Millett, J. H. Przytycki, R. Ricca, and R. Sazdanovic (Springer International Pub- lishing, Cham, 2019) pp. 449–456
work page 2019
-
[46]
Black holes and topological surgery
S. Antoniou, L. H. Kauffman, and S. Lambropoulou, Black holes and topological surgery (2018), arXiv:1808.00254 [math.GT]
work page internal anchor Pith review Pith/arXiv arXiv 2018
-
[47]
Detecting and visualizing 3-dimensional surgery
S. Antoniou, L. H. Kauffman, and S. Lambropoulou, Detecting and visualizing 3-dimensional surgery (2018), arXiv:1811.08384 [math.GT]
work page internal anchor Pith review Pith/arXiv arXiv 2018
-
[48]
Milnor,Topology from the Differentiable Viewpoint (University Press of Virginia, 1965)
J. Milnor,Topology from the Differentiable Viewpoint (University Press of Virginia, 1965)
work page 1965
-
[49]
J. W. Milnor and J. D. Stasheff,Characteristic Classes. (AM-76)(Princeton University Press, 1974)
work page 1974
- [50]
-
[51]
S. Antoniou and S. Lambropoulou, Extending topological surgery to natural processes and dynamical systems, PLoS One12, e0183993 (2017)
work page 2017
-
[52]
A. H. Wallace, Modifications and cobounding manifolds, Canadian Journal of Mathematics12, 503–528 (1960)
work page 1960
-
[53]
W. B. R. Lickorish, A representation of orientable com- binatorial 3-manifolds, Annals of Mathematics76, 531 (1962)
work page 1962
-
[54]
R. D. Sorkin, Topology change and monopole creation, Phys. Rev. D33, 978 (1986)
work page 1986
-
[55]
R. D. Sorkin, Non-time-orientable lorentzian cobordism al- lows for pair creation, International Journal of Theoretical Physics25, 877 (1986)
work page 1986
-
[56]
J. L. Friedman, Lorentzian universes from nothing, Clas- sical and Quantum Gravity15, 2639 (1998)
work page 1998
-
[57]
R. Thom, Quelques propri´ et´ es globales des vari´ et´ es diff´ erentiables, Commentarii Mathematici Helvetici28, 17 (1954)
work page 1954
-
[58]
R. E. Stong,Notes on Cobordism Theory(Princeton Uni- versity Press, 1968)
work page 1968
-
[59]
Steenrod,The Topology of Fibre Bundles
N. Steenrod,The Topology of Fibre Bundles. (PMS-14) (Princeton University Press, 1951)
work page 1951
-
[60]
S. W. Hawking and G. F. R. Ellis,The Large Scale Struc- ture of Space-Time, Cambridge Monographs on Mathe- matical Physics (Cambridge University Press, 1973)
work page 1973
-
[61]
R. Penrose,Techniques of Differential Topology in Rela- tivity(Society for Industrial and Applied Mathematics, 1972)
work page 1972
-
[62]
Curiel, A primer on energy conditions, inTowards a Theory of Spacetime Theories, edited by D
E. Curiel, A primer on energy conditions, inTowards a Theory of Spacetime Theories, edited by D. Lehmkuhl, G. Schiemann, and E. Scholz (Springer New York, New York, NY, 2017) pp. 43–104
work page 2017
-
[63]
F. J. Tipler, Singularities and causality violation, Annals of Physics108, 1 (1977)
work page 1977
-
[64]
F. J. Tipler, Energy conditions and spacetime singularities, Phys. Rev. D17, 2521 (1978)
work page 1978
-
[65]
C. W. Lee and R. Penrose, Topology change in general relativity, Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences364, 295 (1978)
work page 1978
-
[66]
D. Gannon, Singularities in nonsimply connected space–times, Journal of Mathematical Physics16, 2364 (1975)
work page 1975
-
[67]
Friedrich, Is general relativity ‘essentially understood’?, Annalen der Physik518, 84 (2006)
H. Friedrich, Is general relativity ‘essentially understood’?, Annalen der Physik518, 84 (2006)
work page 2006
-
[68]
A. Chamblin, Some applications of differential topology in general relativity, Journal of Geometry and Physics13, 357 (1994)
work page 1994
-
[69]
G. W. Gibbons and S. W. Hawking, Kinks and topology change, Phys. Rev. Lett.69, 1719 (1992)
work page 1992
-
[70]
R. J. Low, Kinking number and the Hopf index theorem, 24 Journal of Mathematical Physics34, 4840 (1993)
work page 1993
-
[71]
A. Chamblin, Topology and causal structure (1996), arXiv:gr-qc/9509046 [gr-qc]
work page internal anchor Pith review Pith/arXiv arXiv 1996
-
[72]
A. Chamblin, G. W. Gibbons, and A. R. Steif, Kinks and time machines, Phys. Rev. D50, R2353 (1994)
work page 1994
-
[73]
T. A. Harriott and J. G. Williams, Kinks, Cobordisms and Topology Change, AIP Conference Proceedings861, 374 (2006)
work page 2006
-
[74]
T. A. Harriott and J. G. Williams, Degree of mapping for general relativistic kinks, Nuovo Cimento B Serie120, 915 (2005)
work page 2005
-
[75]
L. J. Alty, Building blocks for topology change, Journal of Mathematical Physics36, 3613 (1995)
work page 1995
- [76]
-
[77]
M. A. Kervaire and J. W. Milnor, Groups of homotopy spheres: I, Annals of Mathematics77, 504 (1963), full publication date: May, 1963
work page 1963
-
[78]
H. B. Lawson and M.-L. Michelsohn,Spin Geometry (PMS-38)(Princeton University Press, 1989)
work page 1989
-
[79]
T. P. Killingback and E. G. Rees, Spinc structures on manifolds, Classical and Quantum Gravity2, 433 (1985)
work page 1985
-
[80]
G. S. Whiston, Lorentzian characteristic classes, General Relativity and Gravitation6, 463 (1975)
work page 1975
discussion (0)
Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.