Pith. sign in

REVIEW 4 major objections 5 minor 3 cited by

Norm of the no-boundary state

T0 review · 4 major / 5 minor · reviewed 2026-08-06 · deepseek-v4-flash

Pith's one-line read The no-boundary state's norm vanishes at one loop because a residual infinite conformal symmetry remains unfixed.

desk verdict New and plausible claim that the one-loop late-time norm of the no-boundary state vanishes from division by the infinite volume of the residual conformal group, but the load-bearing twirled inner product is deferred to unpublished work. read the letter →

arxiv 2506.20547 v2 pith:S43KIGKL submitted 2025-06-25 hep-th gr-qc

classification hep-thgr-qc
keywords no-boundarystatedeSitterquantumgravitystaticpatchentropyone-loopnormconformalisometryobserverspherepartitionfunctionphaseasymptoticstates
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

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

The reading

This paper tries to establish what the no-boundary state of de Sitter quantum gravity is as a quantum state: to one loop, and in the one-sphere sector at late time, its norm is non-negative but exactly zero. The zero arises not from a wrong-sign fluctuation but from a leftover infinite symmetry, the conformal isometry group $SO(d,1)$ of the future sphere, whose infinite volume divides the answer to nothing. The result matters because it separates the late-time norm from the Euclidean sphere partition function, which carries an unexplained phase, and because it says that normalized cosmological correlators in the no-boundary state require insertions, other topologies, or an observer. The paper shows that an observer with a clock soaks up the residual symmetry and restores a large positive norm.

What carries the argument

The load-bearing object is the twirled inner product on asymptotic states, Eq. (3.42): $$\langle\!\langle h|h'\rangle\!\rangle = |Z|\, $S_0^{{D_d/2}}$\int_{SO(d,1)} d\$\alpha$\,\langle h|\hat{U}(\$\alpha$)|h'\rangle,$$ with $D_d = \dim SO(d,1)$. It says that gravity computes the overlap of late-time metric data by averaging over 'conformal twists,' large diffeomorphisms that act as the identity on one asymptotic boundary and as an $SO(d,1)$ conformal transformation on the other. This leaves the conformal isometry of the round sphere as a residual gauge symmetry of the norm. Because the no-boundary wavefunction is $SO(d,1)$-invariant and has no bosonic zero modes, fixing the residual symmetry divides by the infinite volume $\operatorname{vol}(SO(d,1))$, producing a null one-sphere contribution to the norm. In pure $d=3$ gravity the same structure turns the norm computation into the sphere amplitude of an emergent bosonic string with compact target.

What would settle it

Compute the late-time inner product $\langle\!\langle h|h'\rangle\!\rangle$ directly from the gravitational path integral between two asymptotic slices and check whether it equals the $SO(d,1)$ group average of Eq. (3.42) or an ultralocal delta functional. In $d=3$, where the one-sphere sector is one-dimensional, the sharpest test is to calculate the norm beyond one loop and see whether the $\operatorname{vol}(SO(3,1))$ denominator persists; if it does not, the null norm is a one-loop artifact.

Watch

Extended reading notes

Core claim

The paper's central claim is that, to one-loop order and at late Lorentzian time, the one-sphere contribution to the norm of the no-boundary state in general relativity with positive cosmological constant is $$$e^{{S_0}}$\frac{Z\, $S_0^{{-d(d+1)/4}}$}{\operatorname{vol}(SO(d,1))},$$ with $S_0$ the tree-level static patch entropy and $Z\ge 0$. Since $\operatorname{vol}(SO(d,1))$ is infinite, this contribution vanishes: the no-boundary state is null at one loop, and coupling to matter in an $SO(d,1)$-invariant state, including a slow-roll inflaton, does not change that. The same mechanism gives a finite, positive norm when the state is dressed with two worldline observers, producing a result of order $e^{S_0-2\pi m}$ with $m$ the observer mass. The paper proposes that this observer-stabilized norm, rather than the sphere partition function, is the quantum definition of static patch entropy.

Load-bearing premise

The argument stands on the claim that the gravitational inner product between late-time states is a group average over conformal twists, not a simple delta-function overlap; the full derivation is left to later work, and if that inner product were just a delta function, the infinite symmetry volume would never enter and the norm would not vanish.

Editorial extensions

If this is right

  • The sphere partition function of de Sitter gravity is not the late-time norm of the no-boundary state: the norm is non-negative, while the sphere amplitude carries a dimension-dependent phase.
  • At one loop, the leading one-sphere contribution to the norm vanishes, so a nonzero norm and normalized cosmological correlators require other topologies at future infinity, insertions, or an observer.
  • Two observers with clocks, modeled as worldlines with a continuous energy spectrum, fix the residual $SO(1,1)$ symmetry and give a finite norm that reproduces the classical horizon entropy with a $e^{-2\pi m}$ Boltzmann factor.
  • The slow-roll inflaton no-boundary state is also null at one loop, so the $\ell=0$ problem of the no-boundary proposal should be revisited including subleading saddles and other topologies.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • We infer that if the twirled inner product is correct, then any $SO(d,1)$-invariant late-time state without bosonic zero modes will have a vanishing one-sphere norm, making the null result a general feature of de Sitter asymptotic states rather than a special property of the no-boundary state.
  • We infer that the essential role of an observer with infinite entropy yields a testable dichotomy: a finite-entropy detector at future infinity should produce zero norm, meaning the asymptotic Hilbert space is normalizable only relative to an infinitely precise clock.
  • We infer that a two-point function of suitably dressed scalar insertions at future infinity should be finite while the one-point function remains zero, providing a sharp signature of the residual-symmetry mechanism.
Share X Bluesky LinkedIn Reddit HN

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

4 major / 5 minor

Summary. The paper studies the late-time norm of the Hartle-Hawking no-boundary state in Einstein gravity with positive cosmological constant. Its central result is Eq. (3.52): to one loop, the one-sphere contribution to the norm is e^{S0} times a non-negative determinant ratio, times S0^{-D_d/2}, divided by vol(SO(d,1)); since SO(d,1) is noncompact, the norm is null at this order. The argument combines an inner product on asymptotic states that is twirled by the residual SO(d,1) conformal isometries, Eq. (3.42), with the SO(d,1)-invariance and Gaussian stability of the no-boundary wavefunction established in Section 3.4. The paper also shows, in Section 4, that adding a worldline observer with a clock yields a finite positive norm, and it discusses insertions, other topologies, and consequences for static-patch entropy and Polchinski's phase.

Significance. If the central claim survives scrutiny, it is a substantial result: it identifies a concrete mechanism, division by an infinite residual gauge volume, for a null one-loop norm of the no-boundary state, and it separates the Lorentzian late-time norm from the Euclidean sphere partition function with its Polchinski phase. The paper is unusually explicit about its own limitations: the key twirled inner product is deferred to the authors' 'work in progress' [37], and the observer dressing is an explicit assumption. The paper also contains useful technical contributions: explicit conformal-twist zero modes in d=3 and general d (Sections 3.2 and 3.3), an all-loop argument that residual gauge symmetries survive the transverse-traceless gauge fixing (Section 3.6), and a careful tachyonic-scalar analogue in Appendix A. No parameters are fitted, and the powers of S0 in the result are fixed by the normalization of the twist measure rather than chosen to reproduce the claimed behavior.

major comments (4)
  1. [§3.2–3.3, Eq. (3.42)] The one-loop norm (3.52) hinges on the twirled inner product (3.42). In Section 3.2 the derivation is explicitly deferred: 'a complete computation of the inner product will be done elsewhere [37]', and reference [37] is listed as 'work in progress'. In Section 3.3 the same formula is asserted for general d by a structurally identical argument. If the correct inner product on asymptotic states were the ordinary ultralocal product, the group average over SO(d,1) would not appear, the 1/vol(SO(d,1)) factor would be absent, and the one-sphere contribution to the norm would be a finite positive number rather than zero. The supporting arguments for (3.42), namely that the global de Sitter amplitude is the identity evolution, that the closed-universe Hamiltonian vanishes, and that the inner product should be defined as the modulus of that amplitude, are interpretive and include a positivity choice in the path-integral measure. This is the load-bearing step of the paper and must be established in the manuscript or in a published companion.
  2. [§3.5, Eq. (3.52)] Equation (3.52) is a formal expression in which the norm is proportional to 1/vol(SO(d,1)). For the statement that 'the norm vanishes' to be well-defined, the paper must specify how the infinite volume of the noncompact residual group is regularized. In d=3, Eqs. (3.20)–(3.22) give an explicit metric and measure on the twist zero modes, and the volume is that of SO(3,1) with a canonical normalization. In d>3, the measure is stated by analogy in Eq. (3.41) rather than derived. Since the null result is precisely a division by this volume, the paper should provide a regulator, for example a large-time cutoff with a statement about the limit, or an argument that the ratio is regulator-independent. Without this, 'vanishing' is a formal shorthand and not yet a well-defined one-loop number.
  3. [§3.4, Eqs. (3.46)–(3.48)] The non-negativity and absence of zero modes of |Psi_HH|^2 in even d is established in Section 3.4 by representing the quadratic wavefunction as an integrated CFT stress-tensor two-point function, Eq. (3.47), and asserting that Re(c_T) > 0 in all even d. The paper cites [42] for d=4 and says that, using [15], 'those authors have argued that this persists in even d'. This is a plausibility argument rather than a derivation contained in the present paper. Gaussian stability of the wavefunction is load-bearing for (3.52), since a wrong-sign or zero direction in the transverse-traceless fluctuation space would change the structure of the norm integral. A direct computation of the TT fluctuation kernel in general even d, or a precise published reference, is needed for this ingredient.
  4. [§4.1, Eqs. (4.5)–(4.7)] The finite positive norm in the presence of an observer, Eq. (4.7), rests on an assumed dressing of the worldline endpoints. The text states that the Weyl-invariance of the integrated observer probability is 'a similar problem ... whose outcome we do not presently understand but which we assume can be solved'. This is an explicit unverified assumption in the derivation of one of the paper's advertised results. The paper should either prove the existence of such a dressing within the model of Eqs. (4.1)–(4.2), or clearly state in the abstract and introduction that the observer-stabilized norm is conditional on this assumption.
minor comments (5)
  1. [§3.2–3.3] The notation <h|h'> is used both for the ultralocal delta-function inner product and for the group-averaged inner product in Eq. (3.42); it would help to denote the former, for example, by <h|h'>_0 or by an explicit delta-functional.
  2. [Eqs. (3.24), (3.25), (3.52), Table 1] The constant written as a tilde over Z is never explicitly defined in one place as a single non-negative ratio of renormalized determinants; a one-sentence definition before first use would prevent confusion.
  3. [Eq. (3.11) and surrounding text] In the expression for the conformal-twist metric perturbation, the term involving B_a is written with f4(t), but only f1(t), f2(t), and f3(t) are defined; this appears to be a typo for f3(t).
  4. [After Eq. (3.22)] The sentence 'The powers of G can also be guessed from the fact that there are six bosonic zero modes' is specific to d=3; in general d the counting is D_d = d(d+1)/2, so the sentence should be generalized or qualified.
  5. [References [13], [37]] Two references that support central claims are listed as 'work in progress'. If the manuscript is intended for publication, the text should state clearly that the derivation of Eq. (3.42) is available only in a forthcoming companion, or the derivation should be included here.

Circularity Check

0 steps flagged · score 2.0 of 10

No circular reduction: the null norm follows from the twirled SO(d,1)-invariant inner product and the SO(d,1)-invariant no-boundary wavefunction; the main gap is a deferred computation, not a conclusion reused as its own input.

full rationale

The derivation chain is: (1) late-time asymptotic states have an inner product that is the twirled/group-averaged expression (3.42), argued from the global dS amplitude and twist zero modes, with the measure normalized by the ultralocal overlap and the canonically normalized twist metric (3.41); (2) the one-loop Hartle-Hawking wavefunction is SO(d,1)-invariant with no bosonic zero modes (§3.4); (3) hence the one-sphere contribution is e^{S0} Z S0^{-Dd/2}/vol(SO(d,1)) (§3.5). Each step is a genuine input or derivation: the powers of S0 come from the twist normalization, Z is a ratio of renormalized one-loop determinants, and the 1/vol factor is the gauge-fixing remnant of an SO(d,1)-invariant wavefunction under the group-averaged inner product. Nothing is fitted to produce the vanishing norm, and no equation is defined in terms of the result. The paper does leave a load-bearing computation unfinished: §3.2 says 'a complete computation of the inner product will be done elsewhere [37]' and [37] is listed as work in progress by the present authors. The d=3 and d>3 arguments for (3.42) are schematic, and if the true inner product were ultralocal the norm would not vanish. This is a real correctness/completeness risk, but it is not circularity: the paper does not cite a prior self-contained result that already contains the null norm, nor does it redefine inputs to force the outcome. The self-citations to [14] supply background effective-central-charge data in d=3 and do not assume the conclusion. Accordingly the score is 2, reflecting minor load-bearing reliance on the authors' own forthcoming work rather than any derive-from-itself defect.

Assumptions & free parameters 0 free parameters · 7 assumptions · 0 invented entities

The central claim rests on the dS asymptotic-state framework: the norm is computed by integrating |Ψ|^2 over metrics modulo diff×Weyl, with the inner product of asymptotic states twirled over the noncompact conformal group SO(d,1). No free parameters are fitted to data; the S0 dependence and residual volumes are derived from the canonical normalization of the twist zero-mode measure. The unproven elements are the twirled inner product (deferred to [37]), the positive-measure choice, the absence of wavefunction zero modes (argued via CFT positivity), and the observer-endpoint dressing, all of which are domain assumptions rather than fitted quantities.

assumptions (7)
  • domain assumption The late-time norm of a de Sitter state is given by the overlap integral (1.1) over the boundary metric modulo diff×Weyl transformations.
    Proposed in [10]; argued from the gravitational path integral in §3.1-3.3, with a normalization constant A whose value is deferred to [13]. This quotient structure is the source of the residual conformal symmetry.
  • domain assumption The one-loop inner product of asymptotic states is the twirled group average over SO(d,1) conformal twists, Eq. (3.42): ⟨⟨h|h'⟩⟩ = |Z| S0^{D_d/2} ∫ dα ⟨h|U(α)|h'⟩.
    Introduced in §3.2-3.3 as the inner product implied by the global de Sitter amplitude and conformal twists; the complete computation is deferred to [37]. This is the premise that produces the 1/vol(SO(d,1)) factor.
  • domain assumption The gravitational path integral measure is defined so the one-loop inner product is positive, with the one-loop constant |Z| non-negative.
    Stated in §3.3: 'We implicitly choose to define the measure of the gravitational path integral with the one-loop constant |Z| non-negative so that the inner product is positive-definite.'
  • domain assumption The no-boundary wavefunction is SO(d,1)-invariant and is a right-sign Gaussian in physical metric fluctuations with no bosonic zero modes (at one loop).
    Argued in §3.4 by analogy to a CFT stress-tensor two-point function with Re(c_T) > 0 in even d, citing [42,15], and by anomaly cancellation in odd d. This ensures no non-normalizable directions and no zero modes that would alter the 1/vol scaling.
  • ad hoc to paper The worldline observer endpoints can be dressed so that |Ψ_obs|^2 is Weyl-invariant.
    Assumed in §4.1: 'whose outcome we do not presently understand but which we assume can be solved.' The finite observer-stabilized norm in Eq. (4.7) depends on this dressing.
  • domain assumption In odd d, the Weyl anomalies of the wavefunction integrand and the measure cancel, so the quotient by diff×Weyl is consistent.
    Verified to one loop in d=3 (effective central charge 26, §3.2) and argued to persist in general d in §3.4, including contributions of matter.
  • standard math One-loop determinants on the sphere and at future infinity are renormalized by zeta-function methods, yielding finite non-negative constants Z and Z-tilde.
    Used throughout §2.2 and §3; the positivity and finiteness of Z is asserted (citing [28]) rather than evaluated here.

how reviews work

0 comments
Cite this review

Pith. "Pith review of Norm of the no-boundary state." pith.science (2026). https://pith.science/paper/S43KIGKL

@misc{pith2026250620547,
  author       = {Pith},
  title        = {Pith review of: Norm of the no-boundary state},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/S43KIGKL}},
  note         = {Machine review of arXiv:2506.20547}
}
abstract

We consider Einstein gravity with positive cosmological constant coupled to matter in an asymptotically de Sitter universe with sphere boundary at timelike infinity. In this setting we show that, to one-loop order and at late time, the norm of the no-boundary state vanishes, going as $e^{S_0} \frac{Z S_0^{-d(d+1)/4}}{\text{vol}(SO(d,1))}$ with $S_0$ the tree-level entropy of the static patch, $d$ the spacetime dimension, and $Z$ non-negative. We show that the presence of an observer stabilizes the norm to a large, positive value.

Figures

Figures reproduced from arXiv: 2506.20547 by the authors.

Figure 1
Figure 1. Gibbons and Hawking proposed that the logarithm of the sphere partition function of [PITH_FULL_IMAGE:figures/full_fig_p004_1.png] view at source ↗
Figure 2
Figure 2. The sphere partition function of matter can be understood in two equivalent ways. The [PITH_FULL_IMAGE:figures/full_fig_p010_2.png] view at source ↗
Figure 3
Figure 3. The saddle point of the gravitational path integral that computes the late-time no [PITH_FULL_IMAGE:figures/full_fig_p014_3.png] view at source ↗
Figures from the paper (3 more)
Figure 4
Figure 4. Figure 4: The inner product ⟨⟨γ|γ ′ ⟩⟩ between asymptotically de Sitter states corresponds to com￾puting the transition between two late-time slices in the asymptotic future t → ∞. The real-time segment of the contour is the future half of global de Sitter space, and the gluing …
Figure 5
Figure 5. Figure 5: The complex time contour for the inner product of the no-boundary state with itself at [PITH_FULL_IMAGE:figures/full_fig_p029_5.png]
Figure 6
Figure 6. Figure 6: The geodesic connects the south pole S of the sphere in the far future to the north pole N through a trajectory that passes through the Euclidean cap. With the observer, the completeness relation now includes integrals over the positions of the endpoints 1ˆ∝ Z [dγ] dif…

Discussion (0). Sign in to comment.

Forward citations

Cited by 3 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score. Full citation record

  1. Birth of Inflationary Universes via Wineglass Wormholes and their No-Boundary Relatives

    hep-th 2026-05 unverdicted novelty 6.0 of 10

    Wineglass wormholes with a local maximum in the scale factor mediate the birth of inflationary spacetimes and split into background plus no-boundary geometries at small axionic or magnetic charge.

  2. Quantum Liouville Cosmology

    hep-th 2025-12 unverdicted novelty 6.0 of 10

    Timelike Liouville disk path integrals in fixed K-representation produce Hartle-Hawking-like states, a conjecture for all-loop wavefunctions, and a K-independent inner product for 2D quantum cosmology.

  3. Cosmological correlators in gravitationally-constrained de Sitter states

    hep-th 2025-07 conditional novelty 6.0 of 10

    Cosmological correlators in gravitationally constrained de Sitter states are conformally invariant and differ from QFT vacuum correlators, but relational observables with a heavy background state can reproduce QFT results.

Reference graph

Works this paper leans on

55 extracted references · 11 canonical work pages · cited by 3 Pith papers

  1. [37]

    Cotler and K

    J. Cotler and K. Jensen, work in progress

  2. [42]

    Bobev, T

    N. Bobev, T. Hertog, and Y. Vreys, The NUTs and Bolts of Squashed Holography , JHEP 11 (2016) 140, [ 1610.01497]

  3. [15]

    J. M. Maldacena, Non-Gaussian features of primordial fluctuations in single field inflationary models, JHEP 05 (2003) 013, [ astro-ph/0210603]

  4. [1]

    J. B. Hartle and S. W. Hawking, Wave Function of the Universe , Phys. Rev. D 28 (1983) 2960–2975

  5. [2]

    Baumann, Cosmology

    D. Baumann, Cosmology. Cambridge University Press, 7, 2022

  6. [3]

    Maldacena, Comments on the no boundary wavefunction and slow roll inflation , 2403.10510

    J. Maldacena, Comments on the no boundary wavefunction and slow roll inflation , 2403.10510

  7. [4]

    G. W. Gibbons and S. W. Hawking, Action Integrals and Partition Functions in Quantum Gravity, Phys. Rev. D 15 (1977) 2752–2756

  8. [5]

    Polchinski, The phase of the sum over spheres , Phys

    J. Polchinski, The phase of the sum over spheres , Phys. Lett. B 219 (1989) 251–257

Show all 55 references
  1. [6]

    Banihashemi and T

    B. Banihashemi and T. Jacobson, The enigmatic gravitational partition function , Gen. Rel. Grav. 57 (2025), no. 2 43, [ 2411.00267]

  2. [7]

    G. J. Turiaci and C.-H. Wu, The wavefunction of a quantum S1 × S2 universe, 2503.14639

  3. [8]

    Shi and G

    X. Shi and G. J. Turiaci, The phase of the gravitational path integral , 2504.00900

  4. [9]

    V. Ivo, J. Maldacena, and Z. Sun, Physical instabilities and the phase of the Euclidean path integral, 2504.00920

  5. [10]

    Chakraborty, J

    T. Chakraborty, J. Chakravarty, V. Godet, P. Paul, and S. Raju, Holography of information in de Sitter space , JHEP 12 (2023) 120, [ 2303.16316]

  6. [11]

    Godet, Quantum cosmology as automorphic dynamics , 2405.09833

    V. Godet, Quantum cosmology as automorphic dynamics , 2405.09833. 45

  7. [12]

    Collier, L

    S. Collier, L. Eberhardt, and B. M¨ uhlmann, A microscopic realization of dS 3, SciPost Phys. 18 (2025), no. 4 131, [ 2501.01486]

  8. [13]

    Cotler, W

    J. Cotler, W. Harvey, and K. Jensen, work in progress

  9. [14]

    Cotler, K

    J. Cotler, K. Jensen, and A. Maloney, Low-dimensional de Sitter quantum gravity , JHEP 06 (2020) 048, [ 1905.03780]

  10. [16]

    Weinberg, Quantum contributions to cosmological correlations , Phys

    S. Weinberg, Quantum contributions to cosmological correlations , Phys. Rev. D 72 (2005) 043514, [hep-th/0506236]

  11. [17]

    Arkani-Hamed, D

    N. Arkani-Hamed, D. Baumann, H. Lee, and G. L. Pimentel, The Cosmological Bootstrap: Inflationary Correlators from Symmetries and Singularities , JHEP 04 (2020) 105, [1811.00024]

  12. [18]

    Baumann, D

    D. Baumann, D. Green, A. Joyce, E. Pajer, G. L. Pimentel, C. Sleight, and M. Taronna, Snowmass White Paper: The Cosmological Bootstrap , SciPost Phys. Comm. Rep. 2024 (2024) 1, [ 2203.08121]

  13. [19]

    Erbin, J

    H. Erbin, J. Maldacena, and D. Skliros, Two-Point String Amplitudes , JHEP 07 (2019) 139, [1906.06051]

  14. [20]

    Witten, A background-independent algebra in quantum gravity , JHEP 03 (2024) 077, [2308.03663]

    E. Witten, A background-independent algebra in quantum gravity , JHEP 03 (2024) 077, [2308.03663]

  15. [21]

    Maldacena, Real observers solving imaginary problems , 2412.14014

    J. Maldacena, Real observers solving imaginary problems , 2412.14014

  16. [22]

    Chandrasekaran, R

    V. Chandrasekaran, R. Longo, G. Penington, and E. Witten, An algebra of observables for de Sitter space, JHEP 02 (2023) 082, [ 2206.10780]

  17. [23]

    Witten, Bras and Kets in Euclidean Path Integrals , 2503.12771

    E. Witten, Bras and Kets in Euclidean Path Integrals , 2503.12771

  18. [24]

    Casini, M

    H. Casini, M. Huerta, and R. C. Myers, Towards a derivation of holographic entanglement entropy, JHEP 05 (2011) 036, [ 1102.0440]

  19. [25]

    Susskind, Black Holes Hint towards De Sitter Matrix Theory , Universe 9 (2023), no

    L. Susskind, Black Holes Hint towards De Sitter Matrix Theory , Universe 9 (2023), no. 8 368, [2109.01322]

  20. [26]

    Bastianelli and R

    F. Bastianelli and R. Bonezzi, One-loop quantum gravity from a worldline viewpoint , JHEP 07 (2013) 016, [ 1304.7135]

  21. [27]

    G. W. Gibbons, S. W. Hawking, and M. J. Perry, Path Integrals and the Indefiniteness of the Gravitational Action, Nucl. Phys. B 138 (1978) 141–150. 46

  22. [28]

    Anninos, F

    D. Anninos, F. Denef, Y. T. A. Law, and Z. Sun, Quantum de Sitter horizon entropy from quasicanonical bulk, edge, sphere and topological string partition functions , JHEP 01 (2022) 088, [2009.12464]

  23. [29]

    Marolf, I

    D. Marolf, I. A. Morrison, and M. Srednicki, Perturbative S-matrix for massive scalar fields in global de Sitter space , Class. Quant. Grav. 30 (2013) 155023, [ 1209.6039]

  24. [30]

    Henningson and K

    M. Henningson and K. Skenderis, The Holographic Weyl anomaly , JHEP 07 (1998) 023, [hep-th/9806087]

  25. [31]

    Maldacena, G

    J. Maldacena, G. J. Turiaci, and Z. Yang, Two dimensional Nearly de Sitter gravity , JHEP 01 (2021) 139, [ 1904.01911]

  26. [32]

    Moitra, S

    U. Moitra, S. K. Sake, and S. P. Trivedi, Jackiw-Teitelboim gravity in the second order formalism, JHEP 10 (2021) 204, [ 2101.00596]

  27. [33]

    Held and H

    J. Held and H. Maxfield, The Hilbert space of de Sitter JT: a case study for canonical methods in quantum gravity , 2410.14824

  28. [34]

    Cotler and K

    J. Cotler and K. Jensen, Non-perturbative de Sitter Jackiw-Teitelboim gravity , JHEP 12 (2024) 016, [ 2401.01925]

  29. [35]

    Cotler and K

    J. Cotler and K. Jensen, Emergent unitarity in de Sitter from matrix integrals , JHEP 12 (2021) 089, [ 1911.12358]

  30. [36]

    Cotler and K

    J. Cotler and K. Jensen, Isometric Evolution in de Sitter Quantum Gravity , Phys. Rev. Lett. 131 (2023), no. 21 211601, [ 2302.06603]

  31. [38]

    Blommaert, J

    A. Blommaert, J. Kudler-Flam, and E. Y. Urbach, Absolute entropy and the observer’s no-boundary state, 2505.14771

  32. [39]

    Higuchi, Quantum linearization instabilities of de Sitter space-time

    A. Higuchi, Quantum linearization instabilities of de Sitter space-time. 1 , Class. Quant. Grav. 8 (1991) 1961–1981

  33. [40]

    Higuchi, Quantum linearization instabilities of de Sitter space-time

    A. Higuchi, Quantum linearization instabilities of de Sitter space-time. 2 , Class. Quant. Grav. 8 (1991) 1983–2004

  34. [41]

    Chakraborty, J

    T. Chakraborty, J. Chakravarty, V. Godet, P. Paul, and S. Raju, The Hilbert space of de Sitter quantum gravity , JHEP 01 (2024) 132, [ 2303.16315]

  35. [43]

    Chen and G

    C.-H. Chen and G. Penington, A clock is just a way to tell the time: gravitational algebras in cosmological spacetimes, 2406.02116. 47

  36. [44]

    D. Z. Freedman, S. D. Mathur, A. Matusis, and L. Rastelli, Comments on 4 point functions in the CFT / AdS correspondence , Phys. Lett. B 452 (1999) 61–68, [ hep-th/9808006]

  37. [45]

    Gorbenko and L

    V. Gorbenko and L. Senatore, λϕ4 in dS , 1911.00022

  38. [46]

    Castro, N

    A. Castro, N. Lashkari, and A. Maloney, A de Sitter Farey Tail , Phys. Rev. D 83 (2011) 124027, [1103.4620]

  39. [47]

    Castro and A

    A. Castro and A. Maloney, The Wave Function of Quantum de Sitter , JHEP 11 (2012) 096, [1209.5757]

  40. [48]

    Godet, M¨ obius randomness in the Hartle-Hawking state, 2505.03068

    V. Godet, M¨ obius randomness in the Hartle-Hawking state, 2505.03068

  41. [49]

    Anninos, C

    D. Anninos, C. Baracco, S. Brian, and F. Denef, Features of the Partition Function of a Λ > 0 Universe, 2505.11330

  42. [50]

    S. R. Coleman, Why There Is Nothing Rather Than Something: A Theory of the Cosmological Constant, Nucl. Phys. B 310 (1988) 643–668

  43. [51]

    I. R. Klebanov, L. Susskind, and T. Banks, Wormholes and the Cosmological Constant , Nucl. Phys. B 317 (1989) 665–692

  44. [52]

    Ivo, Y.-Z

    V. Ivo, Y.-Z. Li, and J. Maldacena, The no boundary density matrix , JHEP 02 (2025) 124, [2409.14218]

  45. [53]

    Strominger, The dS / CFT correspondence , JHEP 10 (2001) 034, [ hep-th/0106113]

    A. Strominger, The dS / CFT correspondence , JHEP 10 (2001) 034, [ hep-th/0106113]

  46. [54]

    Maldacena, Einstein Gravity from Conformal Gravity , 1105.5632

    J. Maldacena, Einstein Gravity from Conformal Gravity , 1105.5632

  47. [55]

    Marolf and I

    D. Marolf and I. A. Morrison, Group Averaging for de Sitter free fields , Class. Quant. Grav. 26 (2009) 235003, [ 0810.5163]. 48

Pith tools

Reviewed August 6, 2026 · model on record in the stance chip above.