pith. sign in

arxiv: 2604.03185 · v1 · submitted 2026-04-03 · ✦ hep-th

One-point functions in 2D and 4D SUSY Janus

Andreas Karch , Ainesh Sanyal , Ryan C. Spieler , Mianqi Wang This is my paper

Pith reviewed 2026-05-13 18:45 UTC · model grok-4.3

classification ✦ hep-th
keywords Janus interfacesone-point functionsholographic dualitysupersymmetric interfacesconformal field theorysupergravitymarginal operatorsSUSY conformal manifolds
0
0 comments X

The pith

Exact agreement between supergravity and CFT one-point functions holds only for half-BPS Janus interfaces in 4D and 2D.

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

The paper computes one-point functions of the marginal operator dual to a space-varying dilaton for holographic Janus interfaces in both four and two dimensions. It compares results from the strongly coupled supergravity side with the weakly coupled conformal field theory side for interfaces with different amounts of supersymmetry. Exact matching occurs exclusively in the half-BPS cases, whereas interfaces with less supersymmetry agree only to first order in the parameter controlling the dilaton jump. This finding indicates that full weak-strong coupling duality for these interface observables requires maximal supersymmetry.

Core claim

We calculate the one-point functions of the marginal operator L' dual to the space-varying dilaton in 4D and 2D holographic Janus interfaces. Exact agreement between strongly-coupled supergravity and weakly-coupled CFT limits occurs only for the half-BPS interfaces in both 4D and 2D cases, while for other interfaces they agree to first order of the jump parameter. This reinforces that exact weak/strong coupling matching for interface observables on supersymmetric conformal manifolds is exclusive to maximally SUSY interfaces.

What carries the argument

The one-point function of the marginal operator L' dual to the space-varying dilaton across the Janus interface, compared between supergravity and CFT calculations.

If this is right

  • Exact weak/strong coupling matching for interface observables is limited to maximally supersymmetric interfaces.
  • For non-half-BPS interfaces in 4D N=0,1,2 SYM and 2D N=0, higher-order terms in the jump parameter do not match.
  • The result extends previous calculations to include various SUSY levels in both 4D and 2D.
  • Supersymmetric conformal manifolds show special duality properties only at maximal SUSY.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • This pattern may hold for other observables like two-point functions or in different holographic setups.
  • Non-BPS interfaces could require resummation of higher orders to achieve matching, suggesting a different mechanism.
  • Testing the assumption by including interface geometry corrections could reveal where the mismatch originates.

Load-bearing premise

The one-point functions computed in supergravity and in CFT can be directly compared without needing corrections from the interface geometry or from higher-order terms in the jump parameter.

What would settle it

An explicit computation of the next-order term in the jump parameter for a half-BPS interface showing disagreement between supergravity and CFT, or agreement for a non-BPS interface at all orders.

read the original abstract

We calculate the one-point functions of the marginal operator $\mathcal{L}'$ dual to the space-varying dilaton in 4D and 2D holographic Janus interfaces, extending results in arXiv:hep-th/0407073. We compare strongly-coupled supergravity and weakly-coupled CFT limits across $\mathcal{N}=0, 1, 2, 4$ holographic Janus interfaces in 4D SYM, and $\mathcal{N}=0, 4$ Janus interfaces for 2D D1-D5 CFT. Exact agreement between these regimes occurs only for the half-BPS interfaces in both 4D and 2D cases, while for other interfaces they agree to first order of the jump parameter. This result reinforces that exact weak/strong coupling matching for interface observables on supersymmetric (SUSY) conformal manifolds is exclusive to maximally SUSY interfaces.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

1 major / 1 minor

Summary. The manuscript computes one-point functions of the marginal operator L' (dual to the space-varying dilaton) in 4D N=4 SYM and 2D D1-D5 holographic Janus interfaces for N=0,1,2,4 (4D) and N=0,4 (2D) supersymmetry levels. It compares the strongly-coupled supergravity results with weakly-coupled CFT results obtained via conformal perturbation theory in the jump parameter, reporting exact agreement exclusively for half-BPS interfaces and agreement only through linear order in the jump parameter for the remaining cases. This is used to conclude that exact weak/strong-coupling matching for interface observables on SUSY conformal manifolds occurs only for maximally SUSY interfaces.

Significance. If the comparisons hold, the result provides concrete evidence that supersymmetry level controls the presence or absence of higher-order corrections in interface one-point functions, with exact matching protected only in the half-BPS limit. This strengthens understanding of how maximal supersymmetry enables parameter-free weak/strong agreement for defect observables and offers a testable distinction between SUSY classes on conformal manifolds.

major comments (1)
  1. The central claim that exact agreement occurs exclusively for half-BPS interfaces rests on the direct term-by-term comparability of <L'> between the supergravity dilaton profile and the CFT perturbation expansion. This requires that (i) the operator L' has identical normalization on both sides, (ii) the interface geometry induces no additional finite contributions surviving the small-jump limit, and (iii) no higher-order jump terms appear on the strong-coupling side. None of these are independently verified (e.g., via explicit normalization checks or geometry-corrected expansions), rendering the exclusivity conclusion load-bearing on an untested assumption.
minor comments (1)
  1. The abstract states that results extend arXiv:hep-th/0407073; the introduction should explicitly delineate the novel computations (e.g., the 2D D1-D5 cases and the full set of N values) versus prior work to clarify the incremental advance.

Simulated Author's Rebuttal

1 responses · 0 unresolved

We thank the referee for the careful reading and for identifying the key assumptions underlying our comparability between supergravity and CFT results. We address the major comment point by point below and are prepared to incorporate clarifications.

read point-by-point responses

  1. Referee: The central claim that exact agreement occurs exclusively for half-BPS interfaces rests on the direct term-by-term comparability of <L'> between the supergravity dilaton profile and the CFT perturbation expansion. This requires that (i) the operator L' has identical normalization on both sides, (ii) the interface geometry induces no additional finite contributions surviving the small-jump limit, and (iii) no higher-order jump terms appear on the strong-coupling side. None of these are independently verified (e.g., via explicit normalization checks or geometry-corrected expansions), rendering the exclusivity conclusion load-bearing on an untested assumption.

    Authors: We appreciate the referee raising these points on normalization and limits. (i) The normalization of L' is fixed by matching its two-point function coefficient to the standard CFT value in the absence of any interface (as in the vacuum N=4 SYM and D1-D5 literature); this is the same convention used in the referenced arXiv:hep-th/0407073 calculation that we extend, ensuring identical normalizations on both sides via the holographic dictionary. (ii) In the small-jump expansion the interface reduces to a flat defect with a localized perturbation; the one-point function is extracted from the same asymptotic AdS coordinate chart on the gravity side and the same conformal perturbation on the CFT side, so no additional finite geometry terms survive the vanishing-jump limit. (iii) The supergravity solutions are exact for finite jump parameter; their small-jump series therefore contains all orders, and explicit term-by-term comparison shows that higher-order coefficients vanish (or match) only for the half-BPS cases due to supersymmetry protection, while they differ for lower SUSY. These steps are standard in the literature but we can add an appendix with the explicit normalization constants and the first few terms of the expansions to make the verification fully explicit. revision: partial

Circularity Check

0 steps flagged

No circularity: independent supergravity and CFT computations of one-point functions

full rationale

The paper performs explicit calculations of the one-point function of the marginal operator L' separately in the holographic supergravity regime (using the Janus dilaton profile) and in the CFT regime (via conformal perturbation theory in the jump parameter). These independent results are then compared across different SUSY cases, yielding exact agreement only for half-BPS interfaces and first-order agreement otherwise. No derivation step reduces a prediction to a fitted input by construction, no load-bearing self-citation chain is used to justify the central claim, and the extension of prior work (arXiv:hep-th/0407073) supplies background without making the new comparisons tautological. The comparison itself is the output of two distinct methods rather than a renaming or self-definition.

Axiom & Free-Parameter Ledger

1 free parameters · 1 axioms · 0 invented entities

The central claim rests on the validity of holographic duality for Janus interfaces and the ability to isolate the one-point function of the marginal operator in both regimes.

free parameters (1)
  • jump parameter
    Controls the strength of the dilaton variation across the interface; results are reported to first order in this parameter for non-BPS cases.
axioms (1)
  • domain assumption Holographic duality applies to these SUSY Janus interfaces
    Required to equate supergravity calculations with CFT observables.

pith-pipeline@v0.9.0 · 5458 in / 1143 out tokens · 23214 ms · 2026-05-13T18:45:50.801957+00:00 · methodology

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Reference graph

Works this paper leans on

40 extracted references · 40 canonical work pages

  1. [1]

    Clark, D.Z

    A.B. Clark, D.Z. Freedman, A. Karch and M. Schnabl,Dual of the janus solution: An interface conformal field theory,Physical Review D71(2005)

    work page 2005

  2. [2]

    Maldacena,The large-n limit of superconformal field theories and supergravity,International Journal of Theoretical Physics38(1999) 1113–1133

    J. Maldacena,The large-n limit of superconformal field theories and supergravity,International Journal of Theoretical Physics38(1999) 1113–1133

    work page 1999

  3. [3]

    Witten,Anti de sitter space and holography, 1998

    E. Witten,Anti de sitter space and holography, 1998

    work page 1998

  4. [4]

    Freedman, S.D

    D.Z. Freedman, S.D. Mathur, A. Matusis and L. Rastelli,Correlation functions in the cft /ads+1 correspondence,Nuclear Physics B546(1999) 96–118

    work page 1999

  5. [5]

    Witten,Multi-trace operators, boundary conditions, and ads/cft correspondence, 2002

    E. Witten,Multi-trace operators, boundary conditions, and ads/cft correspondence, 2002

    work page 2002

  6. [6]

    Duff, J.T

    M. Duff, J.T. Liu and H. Sati,Complementarity of the maldacena and karch-randall pictures, Physical Review D69(2004)

    work page 2004

  7. [7]

    Aharony, S.S

    O. Aharony, S.S. Gubser, J. Maldacena, H. Ooguri and Y. Oz,Large n field theories, string theory and gravity,Physics Reports323(2000) 183–386

    work page 2000

  8. [8]

    Bill` o, V

    M. Bill` o, V. Gon¸ calves, E. Lauria and M. Meineri,Defects in conformal field theory,Journal of High Energy Physics2016(2016) 1–56

    work page 2016

  9. [9]

    Andrei, A

    N. Andrei, A. Bissi, M. Buican, J. Cardy, P. Dorey, N. Drukker et al.,Boundary and defect cft: Open problems and applications, 2018

    work page 2018

  10. [10]

    Nagasaki, H

    K. Nagasaki, H. Tanida and S. Yamaguchi,Holographic interface-particle potential,Journal of High Energy Physics2012(2012)

    work page 2012

  11. [11]

    Nagasaki and S

    K. Nagasaki and S. Yamaguchi,Expectation values of chiral primary operators in the holographic interface cft,Physical Review D86(2012)

    work page 2012

  12. [12]

    Buhl-Mortensen, M

    I. Buhl-Mortensen, M. de Leeuw, C. Kristjansen and K. Zarembo,One-point functions in ads/dcft from matrix product states,Journal of High Energy Physics2016(2016)

    work page 2016

  13. [13]

    de Leeuw, A.C

    M. de Leeuw, A.C. Ipsen, C. Kristjansen and M. Wilhelm,Introduction to integrability and one-point functions inN= 4sym and its defect cousin, 2017

    work page 2017

  14. [14]

    de Leeuw,One-point functions in ads/dcft,Journal of Physics A: Mathematical and Theoretical53(2020) 283001

    M. de Leeuw,One-point functions in ads/dcft,Journal of Physics A: Mathematical and Theoretical53(2020) 283001

    work page 2020

  15. [15]

    Wang,Taming defects inN= 4 super-yang-mills,Journal of High Energy Physics2020 (2020)

    Y. Wang,Taming defects inN= 4 super-yang-mills,Journal of High Energy Physics2020 (2020)

    work page 2020

  16. [16]

    Komatsu and Y

    S. Komatsu and Y. Wang,Non-perturbative defect one-point functions in planarN= 4 super-yang-mills,Nuclear Physics B958(2020) 115120

    work page 2020

  17. [17]

    He and C.F

    D. He and C.F. Uhlemann,One-point functions for doubly-holographic bcfts and backreacting defects,Journal of High Energy Physics2025(2025) . – 18 –

    work page 2025

  18. [18]

    D. Bak, M. Gutperle and S. Hirano,A dilatonic deformation ofads5and its field theory dual, Journal of High Energy Physics2003(2003) 072–072

    work page 2003

  19. [19]

    D’Hoker, J

    E. D’Hoker, J. Estes and M. Gutperle,Interface yang–mills, supersymmetry, and janus,Nuclear Physics B753(2006) 16–41

    work page 2006

  20. [20]

    D’Hoker, J

    E. D’Hoker, J. Estes and M. Gutperle,Ten-dimensional supersymmetric janus solutions, Nuclear Physics B757(2006) 79–116

    work page 2006

  21. [21]

    Clark and A

    A.B. Clark and A. Karch,Super janus,Journal of High Energy Physics2005(2005) 094–094

    work page 2005

  22. [22]

    D’Hoker, J

    E. D’Hoker, J. Estes and M. Gutperle,Exact half-bps type iib interface solutions i: local solution and supersymmetric janus,Journal of High Energy Physics2007(2007) 021–021

    work page 2007

  23. [23]

    Bobev, F.F

    N. Bobev, F.F. Gautason, K. Pilch, M. Suh and J. van Muiden,Holographic interfaces inN= 4 sym: Janus and j-folds,Journal of High Energy Physics2020(2020)

    work page 2020

  24. [24]

    D. Bak, M. Gutperle and S. Hirano,Three dimensional janus and time-dependent black holes, Journal of High Energy Physics2007(2007) 068–068

    work page 2007

  25. [25]

    Chiodaroli, M

    M. Chiodaroli, M. Gutperle and D. Krym,Half-bps solutions locally asymptotic to ads 3×s 3 and interface conformal field theories,Journal of High Energy Physics2010(2010)

    work page 2010

  26. [26]

    Gutperle and J.D

    M. Gutperle and J.D. Miller,Entanglement entropy at holographic interfaces,Physical Review D93(2016)

    work page 2016

  27. [27]

    S. Baig, A. Karch and M. Wang,Transmission coefficient of super-janus solution, 2024

    work page 2024

  28. [28]

    Chiodaroli, M

    M. Chiodaroli, M. Gutperle and L.-Y. Hung,Boundary entropy of supersymmetric janus solutions,Journal of High Energy Physics2010(2010)

    work page 2010

  29. [29]

    Karch, H

    A. Karch, H. Ooguri and M. Wang,Nonrenormalization theorem forN= (4,4)interface entropy, 2025

    work page 2025

  30. [30]

    Karch and L

    A. Karch and L. Randall,Locally localized gravity,Journal of High Energy Physics2001(2001) 008–008

    work page 2001

  31. [31]

    Karch, H.-Y

    A. Karch, H.-Y. Sun and C.F. Uhlemann,Double holography in string theory,Journal of High Energy Physics2022(2022)

    work page 2022

  32. [32]

    Gaiotto and E

    D. Gaiotto and E. Witten,Supersymmetric boundary conditions inN= 4super yang-mills theory,Journal of Statistical Physics135(2009) 789–855

    work page 2009

  33. [33]

    Gaiotto and E

    D. Gaiotto and E. Witten,s-duality of boundary conditions inN= 4super yang-mills theory, Advances in Theoretical and Mathematical Physics13(2009) 721–896

    work page 2009

  34. [34]

    D’Hoker, J

    E. D’Hoker, J. Estes and M. Gutperle,Exact half-bps type iib interface solutions ii: flux solutions and multi-janus,Journal of High Energy Physics2007(2007) 022–022

    work page 2007

  35. [35]

    Assel, C

    B. Assel, C. Bachas, J. Estes and J. Gomis,Holographic duals of d=3N= 4superconformal field theories,Journal of High Energy Physics2011(2011)

    work page 2011

  36. [36]

    Balasubramanian, P

    V. Balasubramanian, P. Kraus, A. Lawrence and S.P. Trivedi,Holographic probes of anti–de sitter spacetimes,Physical Review D59(1999)

    work page 1999

  37. [37]

    Chicherin and E

    D. Chicherin and E. Sokatchev,N= 4 super-yang-mills in lhc superspace part ii: non-chiral correlation functions of the stress-tensor multiplet,Journal of High Energy Physics2017(2017) . – 19 –

    work page 2017

  38. [38]

    Aharony and E.Y

    O. Aharony and E.Y. Urbach,On type ii string theory onads 3 ×s 3 ×t 4 and symmetric orbifolds, 2024

    work page 2024

  39. [39]

    David, G

    J.R. David, G. Mandal and S.R. Wadia,Microscopic formulation of black holes in string theory, Physics Reports369(2002) 549–686

    work page 2002

  40. [40]

    02 σµ ¯σµ 02 # , whereσ µ = (1, ⃗ σ) and ¯σµ = (−1, ⃗ σ). The charge conjugation matrix is: C=iγ 2γ0 =

    T. Azeyanagi, T. Takayanagi, A. Karch and E.G. Thompson,Holographic calculation of boundary entropy,Journal of High Energy Physics2008(2008) 054–054. – 20 – A The fermion boundary conditions In this appendix we will derive the fermion boundary conditions at the interface for theN= 4 interface from the bulk and interface Lagrangian terms in (4.1) and (4.2)...

    work page 2008