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REVIEW 2 major objections 4 minor 46 references

A More Convex Ising Formulation of Max-3-Cut Using Higher-Order Spin Interactions

T0 review · 2 major / 4 minor · reviewed 2026-08-06 · deepseek-v4-flash

Pith's one-line read Higher-order Ising encoding removes energy barriers for Max-3-Cut

desk verdict Genuinely new discrete encoding for Max-3-Cut, but the continuous-relaxation smoothness claim is not supported and needs a major repair. read the letter →

arxiv 2508.00565 v2 pith:NQ5CJZWN submitted 2025-08-01 cond-mat.stat-mech math-phmath.MPnlin.AOnlin.CGphysics.app-ph

classification cond-mat.stat-mechmath-phmath.MPnlin.AOnlin.CGphysics.app-ph
keywords Max-3-Cuthigher-orderIsingmodelone-hotencodingmachineenergylandscapeanalogcomputingcombinatorialoptimizationPUSO
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

The paper proposes a new encoding of the Max-3-Cut problem for Ising machines, replacing the standard one-hot quadratic penalty with four-spin interaction terms. The central claim is that this higher-order formulation lets a vertex change color through a single spin flip, so valid configurations are no longer separated by energy barriers. The authors show that this barrier-free structure survives when binary spins are relaxed to continuous analog variables, and that in the small cases they analyze the valid ground state stays lowest in energy for all spin amplitudes. On a simulated analog Ising machine benchmark over 70 random graphs, the higher-order formulation solves every instance faster than the standard quadratic baseline and is on average 2.75 times faster than the best empirically rescaled quadratic version.

What carries the argument

The load-bearing object is a higher-order (four-spin) Ising Hamiltonian, an instance of what the paper calls a Polynomial Unconstrained Spin Optimization problem. The quadratic term $A\sum_v\sum_{i\ne j}\sigma_{v,i}\sigma_{v,j}$ stabilizes the one-hot-invariant triplets, while the fourth-order term $B\sum_{(uv)\in E}\sum_{i\ne j}\sigma_{u,i}\sigma_{v,i}\sigma_{u,j}\sigma_{v,j}$ penalizes equal colored edges by coupling, for each color pair, the two spins of one vertex with the two spins of the other. Because the objective uses only even powers of the spins, the Hamiltonian is invariant under global inversion of a triplet, which doubles the number of valid configurations and makes every color transition a single spin flip. The same even-power structure is what keeps the Max-3-Cut solution lowest in energy for all equal-amplitude continuous-spin configurations in the one- and two-vertex analyses.

What would settle it

Run the benchmark on graphs with more than 60 vertices or with deliberately inhomogeneous spin amplitudes, and track the time-to-solution ratio between the higher-order formulation and the rescaled Ising version; if the advantage disappears or reverses, the claim that barrier-free landscape smoothness drives the speedup is falsified. A second decisive test would be to find a rescaling of the quadratic formulation that beats the higher-order formulation on the full 70-instance suite, which would show that the remaining gap comes from parameter tuning rather than from the energy-barrier structure.

Watch

Extended reading notes

Core claim

The central discovery is that Max-3-Cut's energy landscape becomes smoother when the one-hot constraint is written with quadratic terms and the cut objective with fourth-order terms. The paper introduces $H_{\mathrm{HO}} = A \sum_{v}\sum_{i\ne j}\sigma_{v,i}\sigma_{v,j} + B \sum_{(uv)\in E}\sum_{i\ne j}\sigma_{u,i}\sigma_{v,i}\sigma_{u,j}\sigma_{v,j}$, whose valid configurations are one-hot triplets up to global spin inversion; each of the three colors has two spin representations, so color changes are single-spin flips and no intermediate invalid state is required. For two connected vertices with homogeneous spin amplitudes, the paper proves that the Max-3-Cut ground state is lowest in energy for every amplitude $s\in[0,1]$ and every $B/A>0$, whereas the quadratic Ising formulation favors the all-down invalid state at small amplitudes. In an analog Ising machine benchmark with sign-function local fields, the higher-order formulation solves all 70 instances faster than the original Ising formulation and 66 of 70 faster than the rescaled Ising variant, with an average speedup factor of $2.75\pm1.39$ over the latter.

Load-bearing premise

The proof that the higher-order ground state stays valid at every spin amplitude is carried out for two connected vertices under the assumption that the three spins of a triplet always have equal magnitudes, and the paper extends this conclusion to larger graphs and to analog solvers with arbitrary amplitude heterogeneity without a proof.

Editorial extensions

If this is right

  • On the tested benchmark (70 random graphs with up to 60 vertices), the higher-order formulation never loses to the original Ising formulation in time-to-solution, and it solves 28 instances that the quadratic baseline fails within the time limit.
  • The higher-order formulation beats the best rescaled quadratic version on 66 of 70 instances, with a mean speedup factor of 2.75.
  • The barrier-free single-spin-flip property holds for continuous (analog) spin relaxations, not only for binary spins, making the formulation directly usable in analog Ising machines.
  • The energy-landscape analysis on one and two vertices explains the speedup qualitatively, while the empirical rescaling's growing effectiveness with problem size shows that small-building-block analysis alone cannot predict full-system performance.

Reading between the lines

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

  • The same construction — quadratic one-hot constraint plus fourth-order objective — should generalize to Max-$k$-Cut and other $k$-state problems, with each state represented by $k$ spins and the cut penalty written as products over color pairs; whether the barrier-free property persists for $k>3$ is untested.
  • The homogeneous-amplitude assumption in the Appendix C proof is a genuine restriction: for analog solvers with strong amplitude inhomogeneity, the higher-order formulation's ground-state validity could break, and a test with inhomogeneous initial conditions would clarify this.
  • The benchmark relies on a specific sign-function local-field model; on real hardware with different nonlinearities, the speedup factor and even the ranking of formulations could change.
  • The surprising effectiveness of the 0.6 rescaling hints that the dominant bottleneck in the quadratic formulation is the imbalance between linear and quadratic terms, not the energy barriers themselves, since the rescaled version still has barriers yet approaches the higher-order performance.
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Editorial analysis

A structured set of objections, weighed in public.

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

Referee Report

2 major / 4 minor

Summary. The paper proposes a higher-order Ising (PUSO) formulation of Max-3-Cut in which each vertex is represented by three spins with one-hot encoding modulo global spin inversion. Compared with the standard quadratic one-hot Ising formulation, the new formulation doubles the number of valid configurations, allows transitions between logical states via single-spin flips, and yields energy landscapes that, for equal-amplitude paths, keep the valid configurations as ground states at all amplitudes. The authors also present a simulated analog Ising machine benchmark on 70 random graphs of size 5-60, reporting large time-to-solution gains over the standard Ising formulation and a 2.75x average gain over an empirically rescaled quadratic baseline.

Significance. If the continuous-relaxation claims were fully established, the paper would make a useful contribution to Ising-machine encoding methodology: the algebraic derivation of Eq. (5) is exact and contains no fitted constants, the single-spin-flip connectivity property is real, the two-vertex proof in Appendix C is clean, and the benchmark is carefully specified with a hyperparameter grid and a standard TTS metric. The paper also honestly reports that an empirical rescaling of the quadratic baseline closes much of the performance gap, which is an informative result for practitioners. However, the load-bearing structural claim about continuous relaxations is proved only for very small homogeneous-amplitude cases, and a concrete counterexample shows that the relaxed objective is not equivalent to the discrete Max-3-Cut objective on larger instances.

major comments (2)
  1. [Section III and Appendix C] The continuous-relaxation analysis is restricted to paths of equal spin amplitudes, as stated in Section III and as used in the Appendix C proof, where Eq. (C1) enumerates only configurations (±s,±s,±s). This restriction is load-bearing: for K4 with A=1 and B=2, the optimal coloring (red, red, green, blue) has energy -16 under Eq. (5) at unit amplitudes, but assigning amplitude r=sqrt(5/6) to the two red vertices and amplitude 1 to the other two vertices gives 12r^4 - 20r^2 - 8 = -49/3, which is strictly below -16. Thus the relaxed objective can take values below the discrete optimum, and no argument in the paper rules out relaxed minimizers whose sign patterns are suboptimal cuts on non-3-colorable graphs, which include most benchmark instances. The abstract's statement that the smoothness 'remains true' under continuous relaxation and the subsequent 'well-suited for analog IMs' conclusion therefore go beyond what is proved. The authors should either prove a general statement under explicitly stated conditions or clearly restrict the claim to the homogeneous-amplitude setting.
  2. [Section IV, Eq. (9)] The benchmarked dynamics use a sign-function local-field model, not the gradient or stationary-point structure of the continuous energy in Eq. (5). The reported speedup is therefore an empirical property of this particular simulated analog Ising machine, and the paper does not show that the same ordering of formulations would hold on hardware whose dynamics follow the continuous energy landscapes of Eqs. (3) and (5). The phrase 'well-suited for analog IMs' should be qualified accordingly, or the analysis should explicitly connect Eqs. (8)-(9) to the energy functions being minimized.
minor comments (4)
  1. [Section II.B] There is a typo in 'Polynomial Uncostrained Spin Optimization'; it should be 'Polynomial Unconstrained Spin Optimization'.
  2. [Figure 1 caption] The caption states that the minimal energy states are 'connected by a flat, barrier-free energy path', but this is demonstrated only along the equal-amplitude paths considered in the main text; the caption should make this restriction explicit.
  3. [References] References [36] and [40] refer to the same paper by Yamamura, Mabuchi, and Ganguli; they should be consolidated.
  4. [Section IV and Data Availability] The data availability statement says all relevant data are included, but the benchmark instances are only referenced to external generators; providing the exact graph instances and per-instance TTS values would improve reproducibility.

Circularity Check

0 steps flagged · score 2.0 of 10

No significant circularity: the higher-order formulation is an exact construction with no fitted constants; self-citations are present but not load-bearing.

full rationale

The paper's central derivation is self-contained. Equation (5) is a new higher-order Ising energy function whose ground states are verified by direct evaluation on single-vertex and two-vertex cases, with no constants fitted to benchmark data. The continuous-relaxation discussion in Section III and Appendix C is an exact algebraic check under the explicitly stated homogeneous-amplitude assumption, not a fitted prediction. The time-to-solution comparison in Fig. 4 is an empirical benchmark against ground-truth solutions from an external max-k-cut solver, using a hyperparameter grid for each formulation, so the speedup is not forced by construction. The 0.6 rescaling factor in Eq. (7) is imported from prior work and benchmarked rather than fitted in this paper. The main self-citations are to the authors' own earlier papers for the sign-function local-field model (Eq. 9) and for the previous demonstration that rescaling helps Max-3-Cut; these support the simulation setup and the interpretation of the rescaling, but they do not justify the derivation of the higher-order formulation. At most this is a minor reliance on self-citation for a modeling choice, not a circular step. The Appendix C proof's restriction to two connected vertices and equal amplitudes is a limitation, not a circularity, since no claim is made that the proof itself covers general graphs. Overall the central claim has independent content and is externally benchmarked.

Assumptions & free parameters 4 free parameters · 4 assumptions · 0 invented entities

The central claims rest on standard algebraic manipulation, domain assumptions about the analog IM model and the homogeneous-amplitude analysis, and the choice of the 0.6 rescaling from prior work. No new physical entities are introduced.

free parameters (4)
  • B/A ratio (Ising formulation) = varies per instance; grid-searched 0 to 180/N
    Hyperparameter balancing constraint and objective; best value per instance is selected for TTS, so the reported speedup is the optimum over this grid.
  • B/A ratio (higher-order formulation) = varies per instance; grid-searched 10.5/N to 39/N - 0.1
    Same role; different range because terms scale differently. Best value selected.
  • Linear-term rescaling factor 0.6 (rescaled Ising baseline) = 0.6
    Borrowed from Ref. [33] and the authors' prior work [34]; not fitted in this paper but an empirical constant that is load-bearing for the baseline performance.
  • Solver hyperparameters alpha, v_beta, noise gamma, Delta t = alpha in [-10,1], v_beta in [1e-5,1e-1], gamma=0.001, Delta t=0.01
    Grid-searched for the TTS comparison; these affect the absolute speed but are applied equally across formulations.
assumptions (4)
  • domain assumption The analog IM dynamics of Eq. 8 with sign-function local fields (Eq. 9) faithfully model the behavior of analog Ising machines.
    The paper uses this model throughout the benchmark; if real analog hardware behaves differently, the TTS conclusions might change. The model is inspired by simulated bifurcation [14,32].
  • domain assumption Euler-Maruyama discretization with annealing scheme (Eqs. A1-A2) captures the relevant solver dynamics.
    Appendix A specifies the integration; no convergence or accuracy analysis is provided.
  • domain assumption The continuous-relaxation ground-state property can be inferred from the two-vertex, equal-amplitude analysis.
    Appendix C proves the HO ground state is valid for all s in [0,1] and B/A>0, but only for two connected vertices and homogeneous amplitudes; the paper assumes this insight transfers to larger graphs.
  • domain assumption All graphs are Erdős-Rényi with edge probability 0.5; the observed speedup generalizes to other graph classes.
    Section IV uses 10 instances per size from the rudy generator; no other graph distributions are tested.

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Pith. "Pith review of A More Convex Ising Formulation of Max-3-Cut Using Higher-Order Spin Interactions." pith.science (2026). https://pith.science/paper/NQ5CJZWN

@misc{pith2026250800565,
  author       = {Pith},
  title        = {Pith review of: A More Convex Ising Formulation of Max-3-Cut Using Higher-Order Spin Interactions},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/NQ5CJZWN}},
  note         = {Machine review of arXiv:2508.00565}
}
read the original abstract

Many combinatorial optimization problems (COPs) are naturally expressed using variables that take on more than two discrete values. To solve such problems using Ising machines (IMs) - specialized analog or digital devices designed to solve COPs efficiently - these multi-valued integers must be encoded using binary spin variables. A common approach is one-hot encoding, where each variable is represented by a group of spins constrained so that exactly one spin is in the "up" state. However, this encoding introduces energy barriers: changing an integer's value requires flipping two spins and passing through an invalid intermediate state. This creates rugged energy landscapes that may hinder optimization. We propose a higher-order Ising formulation for Max-3-Cut, which is the smallest fundamental COP with multi-valued integer variables. Our formulation preserves valid configurations under single-spin updates. The resulting energy landscapes are smoother, and we show that this remains true even when the binary variables are relaxed to continuous values, making it well-suited for analog IMs as well. Benchmarking on such an IM, we find that the higher-order formulation leads to significantly faster solutions than the Ising baseline. Interestingly, we find that an empirical rescaling of some terms in the Ising formulation - a heuristic proposed in prior work - approaches the performance of the higher-order Ising formulation, underscoring the importance of empirical parameter tuning in COP encodings.

Figures

Figures reproduced from arXiv: 2508.00565 by the authors.

Figure 1
Figure 1. FIG. 1. Normalized energy landscapes for a single vertex, rep [PITH_FULL_IMAGE:figures/full_fig_p003_1.png] view at source ↗
Figure 2
Figure 2. FIG. 2. Energy landscape for a single vertex, represented by a spin triplet, assuming equal spin amplitudes. For the Ising [PITH_FULL_IMAGE:figures/full_fig_p004_2.png] view at source ↗
Figure 3
Figure 3. FIG. 3. Energy landscape for two connected vertices, assuming equal spin amplitudes. (a) For the Ising formulation, the lowest [PITH_FULL_IMAGE:figures/full_fig_p005_3.png] view at source ↗
Figures from the paper (5 more)
Figure 4
Figure 4. Figure 4: FIG. 4. Comparison of time-to-solution between the three formulations (Eqs. 3, 5, and 7) of Max-3-Cut. Panels a and b show [PITH_FULL_IMAGE:figures/full_fig_p006_4.png]
Figure 5
Figure 5. Figure 5: FIG. 5. Normalized energy landscapes for a single vertex, represented by a spin triplet, under the rescaled Ising formulation of [PITH_FULL_IMAGE:figures/full_fig_p008_5.png]
Figure 6
Figure 6. Figure 6: FIG. 6. Energy landscapes of the rescaled Ising formulation for (a) a single vertex, and (b) two connected vertices. We assume [PITH_FULL_IMAGE:figures/full_fig_p009_6.png]
Figure 7
Figure 7. Figure 7: FIG. 7. Energy landscape for two connected vertices, assuming equal spin amplitudes. In contrast to Fig. 3, this figure uses a [PITH_FULL_IMAGE:figures/full_fig_p009_7.png]
Figure 8
Figure 8. Figure 8: FIG. 8. Energy landscape for two connected vertices, assuming equal spin amplitudes. In contrast to Fig. 3, this figure uses a [PITH_FULL_IMAGE:figures/full_fig_p009_8.png]

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Reference graph

Works this paper leans on

46 extracted references · 39 canonical work pages

  1. [1]

    Barahona, M

    F. Barahona, M. Gr¨ otschel, M. J¨ unger, and G. Reinelt, An application of combinatorial optimization to statis- tical physics and circuit layout design, Operations Re- search 36, 493 (1988)

  2. [2]

    De Simone, M

    C. De Simone, M. Diehl, M. J¨ unger, P. Mutzel, G. Reinelt, and G. Rinaldi, Exact ground states of ising spin glasses: New experimental results with a branch- and-cut algorithm, Journal of Statistical Physics 80, 487 (1995)

  3. [3]

    Perdomo, C

    A. Perdomo, C. Truncik, I. Tubert-Brohman, G. Rose, and A. Aspuru-Guzik, Construction of model hamiltoni- ans for adiabatic quantum computation and its applica- tion to finding low-energy conformations of lattice pro- tein models, Physical Review A 78, 012320 (2008)

  4. [4]

    R. Y. Li, R. Di Felice, R. Rohs, and D. A. Lidar, Quan- tum annealing versus classical machine learning applied to a simplified computational biology problem, npj Quan- tum Information 4, 10.1038/s41534-018-0060-8 (2018)

  5. [5]

    Hojny, I

    C. Hojny, I. Joormann, H. L¨ uthen, and M. Schmidt, Mixed-integer programming techniques for the connected max-k-cut problem, Mathematical Programming Com- putation 13, 75 (2021)

  6. [6]

    Poland and T

    J. Poland and T. Zeugmann, Clustering pairwise dis- tances with missing data: Maximum cuts versus nor- malized cuts, in International Conference on Discovery Science (Springer, 2006) pp. 197–208

  7. [7]

    E. G. Rieffel, D. Venturelli, B. O’Gorman, M. B. Do, E. M. Prystay, and V. N. Smelyanskiy, A case study in programming a quantum annealer for hard operational planning problems, Quantum Information Processing 14, 1 (2015)

  8. [8]

    Carlson and G

    R. Carlson and G. L. Nemhauser, Scheduling to minimize interaction cost, Operations Research 14, 52 (1966)

Show all 46 references
  1. [9]

    Lucas, Ising formulations of many np problems, Fron- tiers in physics 2, 74887 (2014)

    A. Lucas, Ising formulations of many np problems, Fron- tiers in physics 2, 74887 (2014)

  2. [10]

    Dominguez, J

    F. Dominguez, J. Unger, M. Traube, B. Mant, C. Ertler, and W. Lechner, Encoding-independent optimization problem formulation for quantum computing, Frontiers in Quantum Science and Technology 2, 1229471 (2023)

  3. [11]

    Honari-Latifpour and M.-A

    M. Honari-Latifpour and M.-A. Miri, Optical potts ma- chine through networks of three-photon down-conversion oscillators, Nanophotonics 9, 4199 (2020)

  4. [12]

    K. P. Kalinin and N. G. Berloff, Simulating ising and n-state planar potts models and external fields with nonequilibrium condensates, Physical review letters 121, 235302 (2018)

  5. [13]

    Mohseni, P

    N. Mohseni, P. L. McMahon, and T. Byrnes, Ising ma- chines as hardware solvers of combinatorial optimization problems, Nature Reviews Physics 4, 363 (2022)

  6. [14]

    H. Goto, K. Endo, M. Suzuki, Y. Sakai, T. Kanao, Y. Hamakawa, R. Hidaka, M. Yamasaki, and K. Tat- sumura, High-performance combinatorial optimization based on classical mechanics, Science Advances 7, eabe7953 (2021)

  7. [15]

    Inagaki, Y

    T. Inagaki, Y. Haribara, K. Igarashi, T. Sonobe, S. Ta- mate, T. Honjo, A. Marandi, P. L. McMahon, T. Umeki, K. Enbutsu, et al., A coherent ising machine for 2000- node optimization problems, Science 354, 603 (2016)

  8. [16]

    Pedretti, F

    G. Pedretti, F. B¨ ohm, T. Bhattacharya, A. Heittmann, X. Zhang, M. Hizzani, G. Hutchinson, D. Kwon, J. Moon, E. Valiante, et al., Solving boolean satisfiability problems with resistive content addressable memories, npj Uncon- ventional Computing 2, 7 (2025)

  9. [17]

    Leleu, Y

    T. Leleu, Y. Yamamoto, P. L. McMahon, and K. Aihara, Destabilization of local minima in analog spin systems by correction of amplitude heterogeneity, Physical review letters 122, 040607 (2019)

  10. [18]

    Farhi, J

    E. Farhi, J. Goldstone, S. Gutmann, and M. Sipser, Quantum computation by adiabatic evolution, arXiv preprint quant-ph/0001106 (2000)

  11. [19]

    Farhi, J

    E. Farhi, J. Goldstone, and S. Gutmann, A quan- tum approximate optimization algorithm, arXiv preprint arXiv:1411.4028 (2014)

  12. [20]

    Hadfield, Z

    S. Hadfield, Z. Wang, B. O’gorman, E. G. Rieffel, D. Ven- turelli, and R. Biswas, From the quantum approximate optimization algorithm to a quantum alternating opera- tor ansatz, Algorithms 12, 34 (2019)

  13. [21]

    R. M. Karp, Reducibility among combinatorial problems, in 50 Years of Integer Programming 1958-2008: from the Early Years to the State-of-the-Art(Springer, 2009) pp. 219–241

  14. [22]

    Dobrynin, A

    D. Dobrynin, A. Renaudineau, M. Hizzani, D. Strukov, M. Mohseni, and J. P. Strachan, Energy landscapes of combinatorial optimization in ising machines, Physical Review E 110, 045308 (2024)

  15. [23]

    Hizzani, A

    M. Hizzani, A. Heittmann, G. Hutchinson, D. Dobrynin, T. Van Vaerenbergh, T. Bhattacharya, A. Renaudineau, D. Strukov, and J. P. Strachan, Memristor-based hard- ware and algorithms for higher-order hopfield optimiza- tion solver outperforming quadratic ising machines, in 2024 ...

  16. [24]

    Valiante, M

    E. Valiante, M. Hernandez, A. Barzegar, and H. G. Katz- graber, Computational overhead of locality reduction in binary optimization problems, Computer Physics Com- munications 269, 108102 (2021)

  17. [25]

    B¨ ohm, T

    F. B¨ ohm, T. V. Vaerenbergh, G. Verschaffelt, and G. Van der Sande, Order-of-magnitude differences in computational performance of analog ising machines in- duced by the choice of nonlinearity, Communications Physics 4, 149 (2021)

  18. [26]

    N. G. Berloff, M. Silva, K. Kalinin, A. Askitopoulos, J. D. T¨ opfer, P. Cilibrizzi, W. Langbein, and P. G. Lagoudakis, Realizing the classical xy hamiltonian in polariton simu- lators, Nature materials 16, 1120 (2017)

  19. [27]

    A. D. King, W. Bernoudy, J. King, A. J. Berkley, and T. Lanting, Emulating the coherent ising machine with a mean-field algorithm, arXiv preprint arXiv:1806.08422 (2018)

  20. [28]

    Ercsey-Ravasz and Z

    M. Ercsey-Ravasz and Z. Toroczkai, Optimization hard- ness as transient chaos in an analog approach to con- straint satisfaction, Nature Physics 7, 966 (2011)

  21. [29]

    H. Goto, K. Tatsumura, and A. R. Dixon, Combinatorial optimization by simulating adiabatic bifurcations in non- linear hamiltonian systems, Science advances5, eaav2372 (2019)

  22. [30]

    S. K. Vadlamani, T. P. Xiao, and E. Yablonovitch, Physics successfully implements lagrange multiplier op- timization, Proceedings of the National Academy of Sci- ences 117, 26639 (2020)

  23. [31]

    Reifenstein, T

    S. Reifenstein, T. Leleu, T. McKenna, M. Jankowski, M.- G. Suh, E. Ng, F. Khoyratee, Z. Toroczkai, and Y. Ya- 11 mamoto, Coherent sat solvers: a tutorial, Advances in Optics and Photonics 15, 385 (2023)

  24. [32]

    Kanao and H

    T. Kanao and H. Goto, Simulated bifurcation for higher- order cost functions, Applied Physics Express 16, 014501 (2022)

  25. [33]

    Sakaguchi, K

    H. Sakaguchi, K. Ogata, T. Isomura, S. Utsunomiya, Y. Yamamoto, and K. Aihara, Boltzmann sampling by degenerate optical parametric oscillator network for structure-based virtual screening, Entropy 18, 365 (2016)

  26. [34]

    De Prins, J

    R. De Prins, J. Lamers, P. Bienstman, G. Van der Sande, G. Verschaffelt, and T. Van Vaerenbergh, How to in- corporate external fields in analog ising machines, arXiv preprint arXiv:2505.08796 (2025)

  27. [35]

    Leleu, Y

    T. Leleu, Y. Yamamoto, S. Utsunomiya, and K. Aihara, Combinatorial optimization using dynamical phase tran- sitions in driven-dissipative systems, Physical Review E 95, 022118 (2017)

  28. [36]

    Yamamura, H

    A. Yamamura, H. Mabuchi, and S. Ganguli, Geometric landscape annealing as an optimization principle under- lying the coherent ising machine, Physical Review X 14, 031054 (2024)

  29. [37]

    Rinaldi, Rudy, a graph generator,https://www-user

    G. Rinaldi, Rudy, a graph generator,https://www-user. tu-chemnitz.de/~helmberg/rudy (1998)

  30. [38]

    R. D. Prins, Graph instances from the rudy generator (5 to 50 nodes, edge probability 0.5) (2025)

  31. [39]

    Wiegele, Biq mac library - a collection of max-cut and quadratic 0-1 programming instances of medium size (2007)

    A. Wiegele, Biq mac library - a collection of max-cut and quadratic 0-1 programming instances of medium size (2007)

  32. [40]

    Yamamura, H

    A. Yamamura, H. Mabuchi, and S. Ganguli, Geomet- ric landscape annealing as an optimization principle un- derlying the coherent ising machine, Phys. Rev. X 14, 031054 (2024)

  33. [41]

    Lamers, G

    J. Lamers, G. Verschaffelt, and G. Van der Sande, Using continuation methods to analyse the difficulty of prob- lems solved by ising machines, Communications Physics 7 (2024)

  34. [42]

    De Prins, G

    R. De Prins, G. Van der Sande, P. Bienstman, and T. Van Vaerenbergh, How to incorporate higher-order interactions in analog ising machines, arXiv preprint arXiv:2507.23621 (2025)

  35. [43]

    Fakhimi and V

    R. Fakhimi and V. Hamidreza, Max k-cut, https:// github.com/qcol-lu/maxkcut (2022)

  36. [44]

    Richoux and J.-F

    F. Richoux and J.-F. Baffier, Automatic error function learning with interpretable compositional networks, An- nals of Mathematics and Artificial Intelligence , 1 (2023)

  37. [45]

    Richoux, J.-F

    F. Richoux, J.-F. Baffier, and P. Codognet, Learning qubo models for quantum annealing: A constraint-based approach, in International Conference on Computational Science (Springer, 2023) pp. 153–167

  38. [46]

    Masuda, S

    N. Masuda, S. Islam, S. Thu Aung, and T. Watanabe, Energy landscape analysis based on the ising model: Tutorial review, PLOS Complex Systems 2, e0000039 (2025)

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