REVIEW
Tailoring Three-Point Functions and Integrability II. Weak/strong coupling match
High Energy Physics - Theory · Submitted 28 Apr 2011 · 40 references
Pith's verdict: A real weak/strong match for three-point functions, with honest caveats about the sketch and the SU(3) generality.
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Referee report
The paper
The paper claims
In a classical long-string limit, weak and strong coupling give the same three-point function of single-trace operators in planar $N=4$ super Yang–Mills, provided the two heavy operators differ only by roots added to existing classical cuts
The reading
What carries the argument
Three ingredients carry the argument. First, Landau–Lifshitz coherent states: the exact Bethe eigenstates of the long operators are replaced by unentangled tensor products $|u(1)⟩⊗...⊗|u(J)⟩$ with $u(σ)$ slowly varying, which reproduces classical averages such as the energy $⟨H⟩ = (λ/2J)∫(dσ/2π) ∂_σ u ∂_σ u$ up to $1/J$ corrections, and turns the three-point contraction into $C^{123}_{••◦} = [(j_1+j_2)!/(j_1! j_2!)] √(j!/(j_1! j_2! j_3!)) ∫(J dσ/2π) u_1^{j_1} u_2^{j_2} u_3^{j_3}$. Second, the Frolov–Tseytlin limit of the holographic three-point function, in which the factor $1/...$ localizes the Euclidean time integral at $τ≈1/κ$ while the profile $u$ varies slowly, so the two-dimensional worldsheet integral collapses to the same one-dimensional $σ$ integral. Third, the back-reaction criterion: comparing the overlap $I = exp[(J/2π)∫dσ log(1+...)]$ for the three ways of adding the missing roots shows that only deformations scaling as $δu ∼ l/J$ (roots added to existing cuts) leave $I=1$, while $δu ∼ √l/J$ (roots outside the cuts) or roots at infinity give $|I| ∼ e^{-cl}$ or power suppression.
Extended reading notes
Core claim
The central claim is an exact match, in the Frolov–Tseytlin classical limit, between the weak-coupling and strong-coupling values of the ratio $r=|C^{123}_{••◦}/C^{123}_{◦◦◦}|$, where the denominator is the known three-chiral-primary structure constant with the same charges. Both sides reduce to $r = |(v_1^{j_1} v_2^{j_2} v_3^{j_3})^{-1} (2J)^{-1} ... |$ — more precisely, to the normalized integral of $u_1^{j_1} u_2^{j_2} u_3^{j_3}$ over the spin-chain coordinate $σ$ evaluated on the classical profile of the heavy state, with $v_a = J_a/J$ the point-like-string direction. The weak-coupling derivation builds this from coherent states and a conformal-like gauge choice $(j_1+j_2-j_3) u_1 u_2 u_3 ...$ that kills the overlap between the two heavy operators, which is exactly the Virasoro constraint of the strong-coupling side. The strong-coupling derivation gets it from the localization of the boundary-to-bulk propagator at $τ=0$ in the Frolov–Tseytlin limit $κ→∞$ with $κ ∂_τ u$ fixed. The paper then shows, numerically against the exact tree-level formulae and analytically in a solvable case, that the match holds only when the extra Bethe roots that reconcile the R-charges of the two heavy operators are added to cuts that were already open; roots sent to infinity suppress the answer by powers $J^{-n/2}$, and roots placed at finite values outside the cuts change it by an order-one amount.
Load-bearing premise
The weak-coupling side rests on replacing the exact, highly entangled Bethe eigenstates of the two long operators by unentangled product coherent states and assuming this replacement captures the leading large-$J$ three-point contraction; the authors describe their derivation as a sketch and leave the detailed filling-in to the reader.
Editorial extensions
If this is right
- The weak/strong match for structure constants is as general as the corresponding match for the spectrum: it holds for any classical string solution with nontrivial motion on $S^5$ that admits the Frolov–Tseytlin limit, not just the folded string checked numerically.
- The classical three-point function of two heavy and one light operator is determined entirely by the overlap of the two heavy coherent states, so the answer is a single $σ$ integral rather than the determinant-and-partition sums of the exact tree-level formula.
- The result extends to non-protected short operators: the only change is a combinatorial prefactor $D$ read off from the coefficients of the traces in $O_3$, giving $C^{123}_{•••} = D∫(J dσ/2π) u_1^{j_1} u_2^{j_2} u_3^{j_3}$, exact and independent of the classical limit.
- The same coherent-state method applies to any large-$N$ gauge theory with a semiclassical spin-chain limit, since integrability is needed only for the strong-coupling comparison, not for the weak-coupling computation.
- A concrete sharpening of the operator-identification problem: 'the two heavy operators are roughly conjugate' is not enough to fix the answer, and the paper supplies the rule (add roots to existing cuts) that makes the statement precise.
Reading between the lines
- If the tree-level match is the first term of a systematic $1/κ^2$ expansion on both sides, then the natural next test is the order-$1/κ^2$ correction: the paper notes that expanding the holographic formula to next order should be compared with the one-loop Hamiltonian insertion plus two-loop wavefunction correction at weak coupling, and an optimistic reading is agreement up to two loops.
- The back-reaction analysis suggests a general principle beyond this model: any semiclassical three-point function of two heavy and one light state is dominated by wavefunction overlap, so the same 'which deformation is soft' criterion should govern which heavy-heavy-light correlators are computable classically in other holographic pairs.
- The result gives a target for an all-loop conjecture: since the spectrum match in this limit was a stepping stone to discretized Bethe equations, the single-integral structure constant formula is a candidate classical limit that a conjectured finite-$J$ formula should reproduce.
- The paper's own remark that the exact tree-level expression is far more complicated than the coherent-state answer suggests the simplification should be derivable directly from the exact formula; doing so would indicate how to handle the case where all three operators are classical.
Original abstract
We compute three-point functions of single trace operators in planar N=4 SYM. We consider the limit where one of the operators is much smaller than the other two. We find a precise match between weak and strong coupling in the Frolov-Tseytlin classical limit for a very general class of classical solutions. To achieve this match we clarify the issue of back-reaction and identify precisely which three-point functions are captured by a classical computation.
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.
The abstract, sentence by sentence
We compute three-point functions of single trace operators in planar N=4 SYM. We consider the limit where one of the operators is much smaller than the other two. We find a precise match between weak and strong coupling in the Frolov-Tseytlin classical limit for a very general class of classical solutions. To achieve this match we clarify the issue of back-reaction and identify precisely which three-point functions are captured by a classical computation.
background contribution method result interpretation main claim
| # | sentence | role | the authors' own work | states the main conclusion | strength |
|---|---|---|---|---|---|
| s0 | We compute three-point functions of single trace operators in planar N=4 SYM. | contribution 0.98 | 0.95 | 0.05 | asserted 1.00 |
| s1 | We consider the limit where one of the operators is much smaller than the other two. | method 0.58 | 0.60 | 0.03 | asserted 0.89 |
| s2 | We find a precise match between weak and strong coupling in the Frolov-Tseytlin classical limit for a very general class of classical solutions. | result 1.00 | 0.94 | 0.85 | asserted 1.00 |
| s3 | To achieve this match we clarify the issue of back-reaction and identify precisely which three-point functions are captured by a classical computation. | method 0.66 | 0.94 | 0.11 | asserted 1.00 |
What was examined, and what was not
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Figures
Figures reproduced from arXiv:1104.5501 by the authors.
References
How later papers used it
45 later papers cite it
1 later paper by other authors is listed below: 1 used its method or tool.
Uses its method or tool 1 of 5 papers with this label
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Followed this paper in using coherent states to approximate the two heavy operators.
Holographic 3-point function at one loop (2011) · 1.00 · paraphrased: the licence does not allow quoting
How the literature uses it
45 arXiv papers cite this in 115 sentences
Papers citing it · 70 sentences without a confident label
Contests it 1 paper
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This means that the match between the tree-level gauge theory answer and the leading Frolov-Tseytlin limit on the string side [ref] found in [ref] does not extend beyond one-loop.
Holographic 3-point function at one loop · Introduction, summary and conclusion · contest 0.79
Builds on it 3 papers
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The work of [ref] can thus be seen as a natural extension of the work of [ref] to 3-point correlation functions, using the prescription of [ref] for two semi-classical operators and a light chiral primary operator in the $SU(3)$ sector of $=4$ SYM theory.
Holographic 3-point function at one loop · Introduction, summary and conclusion · 0.97
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The determinant representations allowed to generalise the results of [ref] to the case of 3 non-BPS fields in the EGSV configuration [ref] , to the case when one of the fields is $su(3)$ type [ref] , and extend the result to the one-loop order [ref] .
String Bits and the Spin Vertex · Introduction · 0.91
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The strong coupling results presented in section [ref] can be generalized to the $SU(3)$ sector [ref] .
On four-point functions and integrability in N=4 SYM: from weak to strong coupling · Conclusions and discussion · 0.83
Uses its method or tool 5 papers
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The prescription of [ref] gives in our case [Note that the unconventional powers of $κ$ are due to a rescaling of the time coordinate (see App. [ref]).]
On Three-point Functions in the AdS_4/CFT_3 Correspondence · The holographic approach · 0.94
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Let us now prove analytically the match between weak and strong coupling for the four-point functions of interest.[We will follow closely the logic of section 3 of [ref] , to where we refer the reader for more details.] We will use an alternative approach to the one presented in section [ref] and used in the previous subsection.
On four-point functions and integrability in N=4 SYM: from weak to strong coupling · Analytics: four-point functions from coherent states · 0.83
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Following [ref] we use coherent states to approximate the two heavy operators.
Holographic 3-point function at one loop · Gauge theory side: Non-extremal 3-point functions · 1.00
Compares with it 4 papers
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Comparing this result with the one for the dual gauge theory, Eq. [ref], it is evident that the leading terms in both sides perfectly match as already pointed out in [ref] .
Holographic 3-point function at one loop · Comparison with gauge theory at one loop order · 0.96
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The tree level weak coupling result matches the leading order expansion in $g/L_1$ of the string theory result, denoted as $C_123^tree$ [ref] (see also [ref] ).
Quantum Integrability for Three-Point Functions · Comparison with string theory · 0.98
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In [ref] the authors evaluated the three point function of a chiral primary and two heavy (non-chiral) operators using integrability in a certain large charge limit and showed that this agreed with that obtained at strong coupling in [ref] .
Structure constants of $\beta$ deformed super Yang-Mills · Introduction · 0.81
Cites it as background 22 papers
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Recall from the discussion in [ref] that the other two choices for the positions of the extra roots of $Ø_1$ are i) to put them at finite positions outside the existing cuts of $Ø_2$ and ii) to put them at infinity.
On four-point functions and integrability in N=4 SYM: from weak to strong coupling · Numerics: $SU(2)$ folded string · 0.86
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In [ref] , a class of tree-level 3-point functions of states that live in scalar $su(2)$ sectors[More than one $su(2)$ sector is involved in these 3-point functions.] were formulated in XXX spin-$1/2$ chain terms, and Izergin-Korepin sum expressions were obtained for their structure constants.
Variations on Slavnov's scalar product · Tree-level SYM$_4$ structure constants that can be expressed in determinant form · 0.92
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In [ref] , Escobedo, Gromov, Sever and Vieira studied 3-point functions of three gauge-invariant single-trace length-$N_i$ operators, $_i(x_i)$, $i ∈{1, 2, 3}$, that are composed of elementary scalars in $SU(2)$ subsectors of $𝒩 = 4$ supersymmetric Yang-Mills theory [ In [ref] , ${_i}$, $i ∈{1, 2, 3}$ are chosen such that their lengths $L_i$ satisfy non-extremal length conditions, $L_i < L_j + L_k$ for any distinct ${i, j, k}$, and further, they are characterized by rapidity variables ${x_i}$, such that they are non-BPS (${x_i}$ has finitely many elements that are finite, rather than infinite), and have well-defined conformal dimensions (the elements of ${x_i}$ satisfy Bethe equations).].
Partial domain wall partition functions · A brief history of partial domain wall configurations · 0.94
What it cites · 69 sentences without a confident label
Builds on 2 papers
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In this paper we consider a generalization of the setup of figure [ref] studied in [ref] , namely we consider $SU(3)$ operators made out of $SU(3)$ complex scalars as indicated in ([ref]), see figure [ref]a.
Tailoring Three-Point Functions and Integrability · Introduction · 1.00
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We then present a slight generalization of the three-point function of two large classical operators and one small BPS operator considered in [ref] .
Holographic three-point functions of semiclassical states · Strong coupling · 0.98
Uses the method or tool of 1 paper
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After some slight modifications described in the main text of [ref] , the codes given in the appendices of [ref] can (and were) used to compute the cases when some roots are at infinity.] For example, if we wanted to reproduce the first point for $α=1/4$ in figure [ref], we would simply run to obtain $r=0.976868082298$.
Tailoring Three-Point Functions and Integrability · Tailoring numerics · 0.94
Compares with 5 papers
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We will first check this claim by comparing [ref] with the exact tree-level results of [ref] .
Tailoring Three-Point Functions and Integrability · $SU(2)$ Folded string warm-up · 0.93
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Our result is analogous to the match observed in the spectrum problem [ref] and we hope it can be equally inspiring in guessing an all-loop interpolation for structure constants as done for the spectrum in [ref] .
Bethe Ansatz for Quantum Strings · Conclusion and open problems · 0.94
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Our result is analogous to the match observed in the spectrum problem [ref] and we hope it can be equally inspiring in guessing an all-loop interpolation for structure constants as done for the spectrum in [ref] .
Long-Range PSU(2,2|4) Bethe Ansaetze for Gauge Theory and Strings · Conclusion and open problems · 0.94
Cites as background 22 papers
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This is the same [ref] as the famous Frolov-Tseytlin limit [ref] which corresponds to $λ,J→∞$ with $λ/J^2 ≪1$.
Spin chains and string theory · Introduction · 0.80
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This is the same [ref] as the famous Frolov-Tseytlin limit [ref] which corresponds to $λ,J→∞$ with $λ/J^2 ≪1$.
Rotating string solutions: AdS/CFT duality in non-supersymmetric sectors · Introduction · 0.80
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These were studied recently at weak [ref] and strong coupling [ref] .
On three-point correlation functions in the gauge/gravity duality · Introduction · 0.98
Discussion
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