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Effects of D-instantons

High Energy Physics - Theory · Submitted 20 Jan 1997 · 39 references

Pith's verdict: The one-instanton R^4 calculation is solid; the SL(2,Z) Eisenstein completion is an honestly labelled conjecture whose instanton coefficients the paper never actually computes.

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arXiv IDhep-th/9701093 (version 3)
CitationCambridge, Michael B.Green (DAMTP, Michael Gutperle (DAMTP, U.K.), U.K). "Effects of D-instantons." arXiv:hep-th/9701093 (1997). https://pith.science/paper/hep-th/9701093
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The paper

The paper claims

A single D-instanton may fix the exact coefficient of the $R^4$ interaction in type IIB string theory, and the way it does so suggests the perturbative series stops at one loop.

The reading

Type IIB string theory contains a point-like euclidean object, the D-instanton, which couples to the Ramond–Ramond scalar and carries an action of $2πiτ$ with $τ=C^{(0)}+ie^{-φ}$. This paper asks what such an object does to the low-energy effective action: how to compute in its background, and what the resulting nonperturbative terms look like. The authors show that the sixteen fermionic zero modes of the background must be integrated over, and that doing so generates explicit one-instanton corrections — including a correction to the $R^4$ term whose tensor structure matches the known tree-level and one-loop contributions. Feeding in the spectrum of multiply-charged instantons obtained by T-duality from wrapped D-particle world-lines, they then conjecture that the whole $R^4$ coefficient is a single $SL(2,ℤ)$-invariant sum over charges, $f(τ,τ̄)=∑_{(p,n)≠(0,0)}τ_2^{3/2}/|p+nτ|^3$. If that conjecture holds, the perturbative expansion of the $R^4$ coupling terminates at one loop, which is a sharp and checkable statement about the theory.

What carries the argument

The load-bearing mechanism is the integration over the sixteen fermionic zero modes of the D-instanton background. In supergravity these modes are generated by applying the sixteen broken supersymmetries to the classical solution, producing the chain of one-point functions for $λ$, $ψ_μ$, $G_{μνρ}$ and the metric; in string theory the same modes appear as fermionic open-string vertex operators attached to a disk with Dirichlet boundary conditions, and the disk amplitudes reproduce the field-theory tadpoles after LSZ reduction. Because a physical amplitude needs sixteen powers of the Grassmann modulus $ε_0$, only processes with enough external states survive, and the resulting contact terms are the instanton corrections. The second piece of machinery is the generalized Eisenstein series $f_s(τ,τ̄)=∑_{(p,n)≠(0,0)}(τ_2/|p+nτ|^2)^s$ at $s=3/2$, which is manifestly $SL(2,ℤ)$-invariant, satisfies the Laplace eigenvalue equation $τ_2^2(∂_{τ_1}^2+∂_{τ_2}^2)E^*=s(s-1)E^*$, and after Poisson resummation produces exactly the tree-level $ζ(3)$ term, the one-loop term, and the sum over instanton charges.

Extended reading notes

Core claim

The paper's central claim is that the D-instanton's contribution to the $R^4$ interaction is not an isolated curiosity but the first term of an $SL(2,ℤ)$-invariant whole. Two ingredients carry it. First, the authors compute the one-instanton background directly, in supergravity and independently on the string world-sheet, by identifying the sixteen fermionic zero modes generated by the broken supersymmetries and integrating over them together with the ten bosonic collective coordinates; this yields an explicit $e^{2πiτ_0}$ correction with the same $R^4$ tensor structure as the tree-level and one-loop terms. Second, T-duality in nine euclidean dimensions relates multiply-wrapped D-particle world-lines to D-instantons of charge $p=mn$, giving a spectrum of multiply-charged instantons with actions $2πi|mn|τ$. Combining these with the known tree-level coefficient $aζ(3)τ_2^{3/2}$ and one-loop coefficient $bτ_2^{-1/2}$ singles out the generalized Eisenstein series $f(τ,τ̄)=∑τ_2^{3/2}/|p+nτ|^3$, whose expansion reproduces both perturbative terms and then a sum of single multiply-charged instanton contributions with no further perturbative terms. The authors are explicit that they have 'by no means proven' this identification, only that it satisfies several stringent constraints.

Load-bearing premise

The argument needs the perturbative $R^4$ terms to vanish beyond one loop, a non-renormalization statement the authors justify only heuristically and explicitly say has not appeared in the literature and deserves further study.

Editorial extensions

If this is right

  • The $R^4$ coefficient in type IIB is conjectured to be exactly $f(τ,τ̄)=∑_{(p,n)≠(0,0)}τ_2^{3/2}/|p+nτ|^3$, so a single function of the complex coupling encodes tree level, one loop, and every instanton sector at once.
  • Perturbative corrections to $R^4$ vanish beyond one loop in the zero-instanton sector; the genus expansion of this particular coupling truncates.
  • The multi-instanton contributions to $R^4$ come only from single instantons of multiple charge $p=mn$, not from separated unit instantons, which instead give higher-derivative interactions because of extra fermionic zero modes.
  • The instanton terms come with an infinite series of perturbative corrections around each charge, beginning with a $τ_2$-independent term that an explicit D-instanton calculation should be able to reproduce as a check.
  • Fixed-angle four-graviton scattering on a Dirichlet disk falls off as a power of the invariants rather than exponentially, so the D-instanton produces point-like behaviour in a theory whose fundamental scattering is normally soft.

Reading between the lines

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

  • If the truncation is real, the $R^4$ coefficient becomes a protected observable: any candidate nonperturbative definition of type IIB has to reproduce the Eisenstein series, which is a much sharper target than matching the two known perturbative coefficients.
  • The same function appears as the spectral sum of the Laplacian on a two-torus with modular parameter $τ$, so the $R^4$ coupling is secretly a heat-kernel-like count of Kaluza–Klein momenta and windings; this is the kind of structure that would let eleven-dimensional or M-theoretic formulations make direct contact with ten-dimensional instanton sums.
  • The point-like fixed-angle behaviour sits uneasily with the expectation that D-particle physics is governed by the eleven-dimensional Planck scale while the D-instanton moduli space knows only the ten-dimensional one; comparing the two scales in a controlled amplitude looks like the cleanest way to see whether the power law survives the inclusion of multiply-charged instantons.
  • Because the fermionic zero-mode count is what forces the truncation, the same argument should apply to other protected couplings with the same number of external states, which suggests a small family of $SL(2,ℤ)$-invariant functions indexed by the eigenvalue $s$ rather than a one-off accident.
Original abstract

Scattering of fundamental states of type IIB supergravity and superstring theory is discussed at low orders in perturbation theory in the background of a D-instanton. The integration over fermionic zero modes in both the low energy supergravity and in the string theory leads to explicit nonperturbative terms in the effective action. These include a single instanton correction to the known tree-level and one-loop $R^4$ interactions. The `spectrum' of multiply-charged D-instantons is deduced by T-duality in nine dimensions from multiply-wound world-lines of marginally-bound D-particles. This, and other clues, lead to a conjectured SL(2,Z) completion of the $R^4$ terms which suggests that they are not renormalized by perturbative corrections in the zero-instanton sector beyond one loop. The string theory unit-charged D-instanton gives rise to point-like effects in fixed-angle scattering, raising unresolved issues concerning distance scales in superstring theory.

The compiled record

The paper's own sentences, arranged, kept beside the review and separate from it. Each label is drawn from a closed vocabulary; the number beside it is the probability the classifier gave that label. Numbers in the tables are the authors', checked by code. No sentence in this record was written by a model.

Compiled by classifier-1.13-20260917 via OpenRouter, question bank abstract-p1-20260923, 2026-09-23: 1 request, 5,040 input tokens, $0.0002 reported.

What the abstract itself states, as probabilities: claims first 0.04 · states limitation 0.82 · human participants 0.01 · controlled comparison 0.03 · randomized assignment 0.01 · states quantitative result 0.22 · compares with prior results 0.68 · mentions code or data availability 0.01.

The abstract, sentence by sentence

arXiv listing abstract v3. Results and the main claim are underlined; .

Scattering of fundamental states of type IIB supergravity and superstring theory is discussed at low orders in perturbation theory in the background of a D-instanton. The integration over fermionic zero modes in both the low energy supergravity and in the string theory leads to explicit nonperturbative terms in the effective action. These include a single instanton correction to the known tree-level and one-loop $R^4$ interactions. The `spectrum' of multiply-charged D-instantons is deduced by T-duality in nine dimensions from multiply-wound world-lines of marginally-bound D-particles. This, and other clues, lead to a conjectured SL(2,Z) completion of the $R^4$ terms which suggests that they are not renormalized by perturbative corrections in the zero-instanton sector beyond one loop. The string theory unit-charged D-instanton gives rise to point-like effects in fixed-angle scattering, raising unresolved issues concerning distance scales in superstring theory.

background contribution method result interpretation main claim

What the classifier reports for each sentence. The number is the probability it gave the label.
#sentencerolethe authors' own workstates the main conclusionstrength
s0 Scattering of fundamental states of type IIB supergravity and superstring theory is discussed at low orders in perturbation theory in the background of a D-instanton. contribution 0.86 0.67 0.07 asserted 0.94
s1 The integration over fermionic zero modes in both the low energy supergravity and in the string theory leads to explicit nonperturbative terms in the effective action. result 0.52 0.84 0.14 asserted 1.00
s2 These include a single instanton correction to the known tree-level and one-loop $R^4$ interactions. result 0.99 0.78 0.18 asserted 1.00
s3 The `spectrum' of multiply-charged D-instantons is deduced by T-duality in nine dimensions from multiply-wound world-lines of marginally-bound D-particles. method 0.55 0.81 0.06 asserted 1.00
s4 This, and other clues, lead to a conjectured SL(2,Z) completion of the $R^4$ terms which suggests that they are not renormalized by perturbative corrections in the zero-instanton sector beyond one loop. interpretation 0.89 0.53 0.46 hedged possibility 0.68
s5 The string theory unit-charged D-instanton gives rise to point-like effects in fixed-angle scattering, raising unresolved issues concerning distance scales in superstring theory. result 0.44 0.77 0.11 asserted 0.99

What kind of paper the classifier reports this is: theoretical result 1.00 · evidence from proof or derivation 0.97.

What was examined, and what was not

sources read
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not examined
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  • figures and tables
  • references and citing sentences
  • relations to other papers
levels run
  • P abstract
not run
  • S sections
  • T body sentences
  • C citations
  • R cross-paper relations

Every quoted sentence on this record is the authors'. Every label is from Pith's closed vocabulary, with the probability shown beside it. Every number in the measurements table is the authors', checked by code. Record as JSON

Figures
Figure 1. An on-shell closed-string state, Ψ, coupling to s open-string fermions on a disk with Dirichlet boundary conditions. An instanton carrying some zero modes corresponds, at lowest order, to a disk world-sheet with open-string states attached to the boundary (as in fig. 1). The functional integration over the disk can be represented in an operator approach by transforming to a parameterization in which the world-sheet is a semi-infinite cylinder with a boundary end-state, |Bi. This state was constructed in [23] to preserve one half of the supersymmetries – both the world-sheet…
Figure 2. The leading contribution to the scattering of four gravitons in the D-instanton background. The sixteen fermionic open strings represent the supermoduli that must be integrated. All disks have boundaries fixed at the same space-time point. Integration over y µ generates a nonlocal four-graviton interaction. Again, contact with the string calculation is made by considering the on-shell amplitude obtained by lopping off the external poles in momentum space, making use of (25), and contracting the free indices with the on-shell wave functions, ζ (r) h (kr) which satisfy krµζ (r)µν = k
Figure 3. Four closed-string states attached to a disk with Dirichlet boundary conditions. Since there are no fermionic moduli this diagram is a sub-process in a complete amplitude. The diagram in fig. 3, is the lowest-order diagram with four gravitons that has no open-string states attached. Even though this only gives a non-zero contribution to the S-matrix in the presence of sources for the fermionic moduli it is instructive to analyze its behaviour in isolation since it illustrates explicitly the point-like effects of Dirichlet boundary conditions. Furthermore, with general external…
Figure 4. World-sheets of order κ 3 with Dirichlet divergences due to open-string degen￾erations, indicated by dashed lines. (a) The divergence arising from the degeneration of the disk which is cancelled by (b), a single degeneration of the annulus. The double degeneration of the annulus is cancelled by other diagrams. All boundaries are mapped to the same space-time point. For example, the divergence illustrated in fig. 4(a) corresponds to a factorization of the four-point function on the open string state and has the form (k3 + k4) · (k1 + k2) Z L a dq q A2(k1, k2; y)A2(k3, k4; y) = ln(
Figure 5. The disconnected world-sheet in fig. 4(b) (a disk and an annulus with coincident boundaries) as seen from the space-time point of view and has the structure of a loop diagram correction to the instanton process. It is noteworthy that the annular world-sheet in fig. 4(b) is really a kind of closed-string loop diagram from the target space point of view since all three boundaries coincide. The disconnected world-sheet of fig. 4(b) is shown from the space-time point of view in fig. 5, where it looks like a loop correction that is expected in the background of an instanton in field…
Figure 6. The light-cone gauge parameterization of the world-sheets describing the scat￾tering of four closed strings with (a) a Neumann boundary and (b) a Dirichlet boundary. Dashed horizontal lines are identified periodically to form closed strings. In the original open-string theory (in which open strings had Neumann boundary conditions in all directions) the insertion of a single boundary in the world-sheet is a unitarity correction (fig. 5(a)), which is represented by the insertion of a boundary at fixed σ, on which the coordinates satisfy ∂nXi = 0 (where ∂n indicates the normal…

Figures reproduced from arXiv:hep-th/9701093 by the authors.

References
How the literature uses it

181 arXiv papers cite this in 341 sentences

Each citing sentence is taken from the citing paper's LaTeX source and typed by Pith's classifier. A label appears at probability 0.8 or more (0.95 for support), a contest at 0.7 or more; the quoted words are the citing authors'. How each label was checked · JSON

Papers citing it · 236 sentences without a confident label

Builds on it 3 papers
Uses its method or tool 4 papers
  • In order to obtain these solutions we will simply sum over images of the $α'$ corrections under the duality group following [ref] .

    Non-Perturbative Corrections and Modularity in N=1 Type IIB Compactifications · Introduction · 0.98

  • As explained in [ref] , the invariance under the discrete subgroup $SL(2,)$ can be restored by summing over images, using similar techniques as the ones used for $R^4$ couplings in toroidal compactifications [ref] .

    D-instantons and twistors · S-duality and A-type D-instanton corrections · 0.86

  • Writing the polarization tensor as $ζ^μ_rν_r = ζ^(μ_r ζ̃^ν_r)$, and evaluating the fermionic integrals in a special frame as described in [ref] , in terms of its $SO(8)$ components, one obtains the following result for $⟨h⟩_4$ [In both, string theory and supergravity, the four-graviton scattering result is given as an integral of the product of four factors of “$⟨h⟩_4$" defined as the tadpole associated with the disk with four fermion zero modes coupled to the graviton and the self dual fourth-rank antisymmetric tensor: [equation] $ϵ_0$ corresponding to the broken supersymmetry - the only covariant combination of four $ϵ_0$'s, two physical momenta and the physical polarization tensor.] : [equation] where: $γ^ij_ab = 1/2γ^[i_aȧγ^j]_ȧb, γ^i$ being the generators of $Cl_8$ Clifford algebra and $R_ijmn ≡k_ik_mζ_(jζ̃_n)$ is the linearized curvature.

    On ${\cal M}$-Theory Dual of Large-$N$ Thermal QCD-Like Theories up to ${\cal O}(R^4)$ and $G$-Structure Classification of Underlying Non-Supersymmetric Geometries · $O(l_p^6)$ Corrections to the Background of CITEMARK60Z in the MQGP Limit · 0.85

Uses its data or values 5 papers
  • Using the ten dimensional values $λ^(10)_(0,0)=3/4$, $λ^(10)_(1,0)=15/4$ and $λ^(10)_(0,1)=12$ determined in [ref] , we deduce that the coefficients of the terms discussed in [ref] satisfy the following set of Laplace eigenvalue equations with source terms, [equation]

    String theory dualities and supergravity divergences · Constraints on the coefficients · 0.99

  • Its dependence with respect to the moduli space parametrised by ${𝒱_2, τ}$ has been already computed in [ref] , and it is captured by the following non-trivial function (see also [ref] )

    On the Species Scale, Modular Invariance and the Gravitational EFT expansion · M-theory on $T^2$ · 0.84

  • More concretely, the correction determined by [ref] is S^(3)_ℛ^4= α'^3g_s^3/2/32 πG ∫d^10 x ∫d^16 θ √(-g)f^(0,0)(τ,τ̅) [(θΓ^mnpθ) (θΓ^qrsθ)ℛ_mnpqrs]^4 + c.c. where $f^(0,0)(τ,τ̅)$ is a modular form [ref] .

    Quantum corrections to eta/s · Introduction · 0.83

Compares with it 6 papers
Cites it as support 2 papers
  • However, this symmetry descends from the usual S-duality action in ten-dimensional string theory, and there is overwhelming evidence that the modular subgroup $SL(2,)$ remains a symmetry at the quantum level (see [ref] and citations thereof).

    S-duality in Twistor Space · Quantum corrections · 0.97

  • Furthermore, in a number of examples from string theory it was actually possible to show that the observable is given by an Eisenstein series itself [ref] .[That Eisenstein series are mostly not square-integrable is no problem in these cases since the object computed (part of a scattering amplitude) is not a wavefunction and not required to be normalisable.]

    Eisenstein series and automorphic representations · A physicist's possible answer · 1.00

Cites it as background 71 papers

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