REVIEW 2 major objections 5 minor 22 references
Towards quantum simulation of lower-dimensional supersymmetric lattice models
T0 review · 2 major / 5 minor · reviewed 2026-08-12 · deepseek-v4-flash
Pith's one-line read Sampling noise from a fixed number of shots can make a supersymmetry-preserving model appear to spontaneously break supersymmetry.
desk verdict A modest but honest proceedings paper: the shot-noise caution is plausible and useful, but underquantified; the statevector baselines are solid and reproducible. read the letter →
The pith
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
The reading
What carries the argument
The object carrying the argument is the supersymmetric quantum-mechanics Hamiltonian $H=\frac{1}{2}(\hat{p}^2+[W'(\hat{q})]^2-W''(\hat{q})\,[\hat{b}^\dagger,\hat{b}])$, whose supercharges satisfy $2H=\{Q,Q^\dagger\}$; because every eigenenergy is non-negative, a zero-energy ground state exists exactly when both supercharges annihilate it, making the ground-state energy the order parameter for spontaneous supersymmetry breaking. The numerical machinery is VQE with a RealAmplitude ansatz, single-qubit rotations plus a reverse-linear chain of CNOT entanglers, minimized by the gradient-free COBYLA optimizer and run 100 times per superpotential and truncation level. The diagnostic that makes the noise visible is the boxplot of those 100 runs placed against the exact diagonalization value: the median, quartiles, and outliers turn a collection of noisy energy measurements into a clear visual statement that the noisy distribution is biased away from zero.
What would settle it
Repeat the harmonic-oscillator VQE on real quantum hardware, or on a simulator that adds gate errors and decoherence, at shot counts from $10^3$ to $10^6$, and record the median ground-state energy as a function of $\Lambda$. If the nonzero median disappears or does not grow with $\Lambda$ when hardware noise is included, the paper's claim that shot noise alone can create a spurious supersymmetry-breaking signal would not hold on actual devices; if the bias persists and shrinks with increasing shots, the shot-noise explanation is confirmed.
Extended reading notes
Core claim
The paper's central claim is that sampling noise, not physics, can masquerade as spontaneous supersymmetry breaking in current quantum-simulation workflows. For the harmonic-oscillator superpotential, exact diagonalization and a noiseless state-vector VQE both give ground-state energy zero for every truncation level $\Lambda$, matching the expectation that supersymmetry is preserved. The VQE runs with 10,000 shots instead give a distribution of energies whose median is positive and increases with $\Lambda$; by the model's standard criterion, nonzero ground-state energy means supersymmetry is spontaneously broken, so this looks like breaking. The authors state directly that this illustrates how noise from a fixed number of shots might be misinterpreted as evidence of spontaneous supersymmetry breaking. In the double-well case, where supersymmetry is genuinely broken, the larger energy scale makes the breaking signal survive the noise, while in the anharmonic-oscillator case bosonic truncation effects already make even the noiseless results deviate beyond $\Lambda=8$.
Load-bearing premise
The warning depends on the assumption that a simulator with 10,000 random samples and the chosen classical optimizer behaves like real quantum hardware; the paper explicitly leaves gate errors and decoherence for future work, so the caution has not yet been demonstrated on actual devices.
Editorial extensions
If this is right
- VQE studies that search for spontaneous supersymmetry breaking should report shot-count dependence, repeating runs at different numbers of shots, before interpreting a nonzero ground-state energy as breaking.
- For the harmonic-oscillator superpotential, shot noise biases the median energy upward with increasing bosonic truncation $\Lambda$, so noiseless-versus-noisy comparisons are needed to separate algorithmic bias from physical signals.
- The double-well superpotential's spontaneous breaking signal is large enough to survive shot noise, so not all supersymmetry-breaking conclusions from VQE are suspect.
- The general-purpose ansatz used here reproduces exact results only for modest $\Lambda$, so reaching the untruncated limit will require a problem-tailored ansatz.
- A more robust route is to compute the low-energy spectrum, for example with variational quantum deflation, rather than only the ground-state energy, since the pairing of excited states is a cleaner supersymmetry diagnostic.
Reading between the lines
- The same spurious-breaking mechanism should apply to any VQE order parameter measured with finite shots and a noisy optimizer, so the caution generalizes beyond supersymmetry to symmetry-breaking searches in other lattice models.
- A testable extension is to quantify how the median bias scales with shot count and truncation level for the harmonic oscillator; if the bias falls as the inverse square root of the shot count, it is purely sampling noise, while a plateau would indicate optimizer bias.
- Comparing noiseless and shot-noise distributions, as the boxplots do, could become a standard low-cost diagnostic for detecting optimizer-versus-noise artifacts before moving to real hardware.
- The truncation-plus-noise interplay seen in the anharmonic-oscillator model suggests that digitization errors and sampling noise may compound, motivating studies that vary both $\Lambda$ and shot count simultaneously.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. This proceedings paper explores the use of the variational quantum eigensolver (VQE) to detect spontaneous supersymmetry breaking in 0+1-dimensional supersymmetric quantum mechanics. The authors encode the model on qubits using one fermionic qubit and B bosonic qubits for Λ=2^B bosonic modes, and study three superpotentials (harmonic oscillator, double well, anharmonic oscillator). For each case they perform 100 VQE runs on Qiskit statevector and shot-noise simulators using the RealAmplitude ansatz and the COBYLA optimizer, comparing the resulting ground-state energy distributions with exact diagonalization. The paper's main observation is that in the presence of shot noise the harmonic-oscillator median ground-state energy appears positive and increases with Λ, which could be misinterpreted as evidence of spontaneous supersymmetry breaking. The authors also provide a tabulation of the Pauli-string resources required for various truncations.
Significance. If the shot-noise caution is quantitatively established, it is a valuable practical warning for VQE-based studies of supersymmetry breaking on near-term quantum hardware, and the paper offers a clean, explicit qubit encoding and resource estimates for the SQM models. The statevector results benchmarked against exact diagonalization support the basic validity of the encoding and the VQE setup. However, the central claim about shot noise currently rests on qualitative inspection of boxplots without numerical values, confidence intervals, or significance tests, and the attribution to the COBYLA optimizer is not tested. The manuscript is explicitly preliminary, and the authors appropriately scope out hardware noise, but the evidentiary basis for the headline finding needs strengthening before it can be considered established.
major comments (2)
- [Section 5, Fig. 4] The central claim that shot noise produces a spurious positive median ground-state energy for the harmonic oscillator is not quantified. The text states that "the median is consistent with a non-zero energy value, which tends to increase with larger Λ," but no numerical medians, interquartile ranges, confidence intervals, or significance tests are reported for the 100 runs. Without these, the reader cannot determine whether the positive median is statistically significant or within the expected finite-sample fluctuation around the true value E0=0, and the Λ-trend is asserted without a fit or a correlation measure. Please report the numerical values and a simple statistical test (e.g., a bootstrap confidence interval for the median or a sign test against zero), and quantify the trend, for example with a rank correlation or a linear fit.
- [Section 5, Fig. 4 and Section 6] The paper attributes the shot-noise discrepancy to the statement that "the COBYLA optimizer struggles to find the minimum in presence of noise." This leaves open the possibility that the positive median is an artifact of the specific interaction between COBYLA and a noisy objective rather than a generic property of finite-shot VQE. To support the general caution, please compare with at least one alternative optimizer (e.g., SPSA or a gradient-based method) under the same shot-noise conditions, or demonstrate the same positive shift with a fixed ansatz parameter set. If the effect is optimizer-specific, the conclusion should be reframed accordingly.
minor comments (5)
- [Section 5, Fig. 4] Please clarify whether the vertical lines for the harmonic oscillator represent the exact diagonalization energy of the truncated Hamiltonian or the continuum result E0=0. Section 3 states that the bosonic truncation explicitly breaks supersymmetry, so it would be helpful to state explicitly how the truncated ED energy behaves for HO as Λ increases.
- [Section 5] The description of the shot-noise simulations is ambiguous: "10000 shot executions for each of the 100 VQE runs" could mean 10,000 shots per Pauli string per energy evaluation or 10,000 shots total per run. Please specify the measurement budget, since the effective shot noise depends on this.
- [Section 5, AHO results] For the anharmonic oscillator, the statevector VQE agrees with exact diagonalization only up to Λ=8, and the text acknowledges this. Please state explicitly in the conclusions that the current ansatz does not scale to larger bosonic truncations for the AHO, and clarify whether the failure is due to optimizer convergence or ansatz expressibility.
- [Figure 4 caption] The caption contains a typo: "different superpontentials" should be "different superpotentials."
- [Section 3] The text says "the Λ states require B qubits, where Λ=2^B"; the notation is correct, but consider adding a brief explanation of why B qubits are sufficient for Λ=2^B bosonic modes.
Circularity Check
No significant circularity: the VQE ground-state energies are benchmarked against exact diagonalization, and the shot-noise caution is an empirical observation rather than a fitted or self-cited prediction.
full rationale
The paper's central derivation chain is self-contained. The target quantity, the ground-state energy, is defined directly by the supersymmetric Hamiltonian in Eq. (1), and the VQE algorithm minimizes that same Hamiltonian to produce an estimate that is then compared against exact diagonalization. This is the intended use of VQE, not a circular reduction: the variational parameters are optimized, but the reported observable (the energy) is an independent quantity defined by the model, and the exact result is computed by a separate classical method. The shot-noise caution in Section 5 is an empirical observation from 100 Qiskit simulator runs with 10,000 shots, presented as boxplots relative to the exact values; it does not rest on any fitted parameter being renamed as a prediction, nor does it invoke a uniqueness theorem. The self-citations to Refs. [6, 8, 9] are contextual: they identify prior efforts, note that prior work did not account for shot noise, and suggest VQD as future work. None of these citations supplies a load-bearing premise for the paper's own results. The skeptical concern about the lack of quantitative significance testing for the median offset is a matter of evidence strength and correctness risk, not circularity, because the observation is not defined in terms of the conclusion. No equation in the paper reduces to its own input, and no known empirical result is merely renamed. Accordingly, the paper exhibits no significant circularity.
Assumptions & free parameters
free parameters (4)
- m (boson mass) =
1
- g (interaction strength) =
1
- mu (double-well parameter) =
1
- Bosonic truncation Lambda =
2, 4, 8, 16, 32, 64
assumptions (5)
- domain assumption Supersymmetric quantum mechanics: the Hamiltonian is H = (1/2){Q, Q-dagger}, and supersymmetry is preserved iff the ground state energy is zero.
- standard math Jordan-Wigner transformation maps fermionic operators to Pauli matrices (Eq. 4).
- domain assumption Truncated harmonic-oscillator basis with Lambda modes provides a valid finite-dimensional regularization of the bosonic operators (Eq. 5).
- domain assumption The Qiskit statevector and shot-noise simulators correctly implement the circuits and sampling statistics.
- domain assumption The RealAmplitude reverse-linear ansatz is expressive enough to approximate the ground state of the truncated Hamiltonian.
Cite this review
Pith. "Pith review of Towards quantum simulation of lower-dimensional supersymmetric lattice models." pith.science (2026). https://pith.science/paper/2CHAWXMC
@misc{pith2026241115083,
author = {Pith},
title = {Pith review of: Towards quantum simulation of lower-dimensional supersymmetric lattice models},
year = {2026},
howpublished = {\url{https://pith.science/paper/2CHAWXMC}},
note = {Machine review of arXiv:2411.15083}
}
read the original abstract
Supersymmetric models are grounded in the intriguing concept of a hypothetical symmetry that relates bosonic and fermionic particles. This symmetry has profound implications, offering valuable extensions to the Standard Model of particle physics and fostering connections to theories of quantum gravity. However, lattice studies exploring the non-perturbative features of these models, such as spontaneous supersymmetry breaking and real-time evolution encounter significant challenges, particularly due to the infamous sign problem. The sign problem obstructs simulations on classical computers, especially when dealing with high-dimensional lattice systems. While one potential solution is to adopt the Hamiltonian formalism, this approach necessitates an exponential increase in classical resources with the number of lattice sites and degrees of freedom, rendering it impractical for large systems. In contrast, quantum hardware offers a promising alternative, as it requires in principle a polynomial amount of resources, making the study of these models more accessible. In this context, we explore the encoding of lower-dimensional supersymmetric quantum mechanics onto qubits. We also highlight our ongoing efforts to implement and check the model supersymmetry breaking on an IBM gate-based quantum simulator with and without shot noise, addressing the technical challenges we face and the potential implications of our findings for advancing our understanding of supersymmetry.
Figures
Figures from the paper (1 more)
Reference graph
Works this paper leans on
-
[1]
Recent progress in lattice supersymmetry: from lattice gauge theory to black holes
D. Kadoh,Recent progress in lattice supersymmetry: from lattice gauge theory to black holes, PoS LATTICE2015(2016) 017 [1607.01170]
work page Pith review arXiv 2016
-
[2]
G. Bergner and S. Catterall,Supersymmetry on the lattice,Int. J. Mod. Phys. A31 (2016) 1643005 [1603.04478]
arXiv 2016
-
[3]
Schaich,Lattice studies of supersymmetric gauge theories, Eur
D. Schaich,Lattice studies of supersymmetric gauge theories, Eur. Phys. J. ST232 (2023) 305 [2208.03580]
arXiv 2023
-
[4]
Preskill,Quantum Computing in the NISQ era and beyond,Quantum 2 (2018) 79 [1801.00862]
J. Preskill,Quantum Computing in the NISQ era and beyond,Quantum 2 (2018) 79 [1801.00862]
arXiv 2018
-
[5]
A. Peruzzo, J. McClean, P. Shadbolt, M.-H. Yung, X.-Q. Zhou, P.J. Love et al.,A variational eigenvalue solver on a photonic quantum processor, Nature Commun.5 (2014) 4213 [1304.3061]
arXiv 2014
-
[6]
Quantum computing for lattice supersymmetry
C. Culver and D. Schaich,Quantum computing for lattice supersymmetry,PoS LATTICE2021(2022) 153 [2112.07651]
work page Pith review arXiv 2022
-
[7]
Observation of Supersymmetry and its Spontaneous Breaking in a Trapped Ion Quantum Simulator
M.L. Cai, Y.K. Wu, Q.X. Mei, W.D. Zhao, Y. Jiang, L. Yao et al.,Observation of supersymmetry and its spontaneous breaking in a trapped ion quantum simulator,Nature Commun. 13 (2022) 3412 [2205.14860]
work page Pith review arXiv 2022
-
[8]
Quantum Computing for the Wess-Zumino Model
C. Culver and D. Schaich,Quantum Computing for the Wess–Zumino Model, PoS LATTICE2022(2023) 008 [2301.02230]
work page Pith review arXiv 2023
Show all 22 references
-
[9]
Schaich and C
D. Schaich and C. Culver,Exploring lattice supersymmetry with variational quantum deflation, PoS LATTICE2024(2024) 212 [2410.11514]
2024 arXiv
-
[10]
Cooper, A
F. Cooper, A. Khare and U. Sukhatme,Supersymmetry and quantum mechanics, Phys. Rept. 251 (1995) 267 [hep-th/9405029]
1995 arXiv
-
[11]
Macridin, A.C.Y
A. Macridin, A.C.Y. Li, S. Mrenna and P. Spentzouris,Bosonic field digitization for quantum computers, Phys. Rev. A105 (2022) 052405 [2108.10793]
2022 arXiv
- [12]
-
[13]
Motta, C
M. Motta, C. Sun, A.T.K. Tan, M.J.O. Rourke, E. Ye, A.J. Minnich et al.,Determining eigenstates and thermal states on a quantum computer using quantum imaginary time evolution, Nature Phys.16 (2019) 205 [1901.07653]
2019 arXiv
-
[14]
Farhi, J
E. Farhi, J. Goldstone and S. Gutmann,A Quantum Approximate Optimization Algorithm, 1411.4028
-
[15]
Hadfield, Z
S. Hadfield, Z. Wang, B. O’Gorman, E.G. Rieffel, D. Venturelli and R. Biswas,From the quantum approximate optimization algorithm to a quantum alternating operator ansatz., Algorithms (Basel)12(2019) 34 [1709.03489]
2019 arXiv
-
[16]
Maiti, D
S. Maiti, D. Banerjee, B. Chakraborty and E. Huffman,Spontaneous symmetry breaking in a 𝑆𝑂(3) non-Abelian lattice gauge theory in2+ 1D with quantum algorithms, 2409.07108
-
[17]
VQE codes for0+ 1supersymmetric quantum mechanics
E. Mendicelli, “VQE codes for0+ 1supersymmetric quantum mechanics.” github.com/emanuele-mendicelli/0p1_Supersymmetric_Quantum_Mechanics, 2024. 9 Towards quantum simulation of lower-dimensional supersymmetric lattice modelsEmanuele Mendicelli
2024
-
[18]
M.J.D. Powell,A direct search optimization method that models the objective and constraint functions by linear interpolation, inAdvances in Optimization and Numerical Analysis, S.GomezandJ.-P.Hennart, eds., (Dordrecht), pp.51–67, SpringerNetherlands(1994), DOI
1994
-
[19]
Ferreira, M.T.S
J.E.V. Ferreira, M.T.S. Pinheiro, W.R.S. dos Santos and R. da Silva Maia,Graphical representation of chemical periodicity of main elements through boxplot,Educación Química 27 (2016) 209
2016
-
[20]
Miháliková, M
I. Miháliková, M. Pivoluska, M. Plesch, M. Friák, D. Nagaj and M. Šob,The Cost of Improving the Precision of the Variational Quantum Eigensolver for Quantum Chemistry, Nanomaterials 12(2022) 243 [2111.04965]
2022 arXiv
-
[21]
Pellow-Jarman, I
A. Pellow-Jarman, I. Sinayskiy, A. Pillay and F. Petruccione,A comparison of various classical optimizers for a variational quantum linear solver,Quantum Information Processing 20(2021)
2021
-
[22]
Higgott, D
O. Higgott, D. Wang and S. Brierley,Variational Quantum Computation of Excited States, Quantum 3 (2019) 156 [1805.08138]. 10
2019 arXiv
Reviewed August 12, 2026 · model on record in the stance chip above.
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