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arxiv: 2604.10025 · v1 · submitted 2026-04-11 · ✦ hep-ph

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Toward selective quantum advantage in hadronic tomography:explicit cases from Compton form factors, GPDs, TMDs, and GTMDs

D. Keller, I. P. Fernando

Authors on Pith no claims yet

Pith reviewed 2026-05-10 16:42 UTC · model grok-4.3

classification ✦ hep-ph
keywords quantum advantagehadronic tomographyCompton form factorsgeneralized parton distributionstransverse momentum distributionsgeneralized TMDsinverse problemsquantum algorithms in QCD
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The pith

Quantum advantage in hadronic physics should be evaluated observable by observable, with CFFs, GPDs, TMDs, and GTMDs as natural targets due to their ill-posed inverse problems.

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

The paper argues that blanket claims of quantum advantage for all of QCD are too broad and instead examines specific observables in hadronic tomography one by one. Compton form factors, generalized parton distributions, transverse-momentum-dependent distributions, and generalized transverse-momentum-dependent distributions are singled out because they are defined through light-front, off-forward, or real-time correlation functions whose extraction from Euclidean lattice data or limited experiments forms an ill-posed inverse problem. Quantum primitives such as Hamiltonian simulation, linear-response methods, amplitude estimation, and quantum deep neural networks are linked to three distinct kinds of advantage that could improve reconstruction accuracy and reduce model dependence. A sympathetic reader would care because these distributions encode the three-dimensional structure of nucleons, and better extraction methods would tighten constraints on nucleon tomography without relying as heavily on ad-hoc parametrizations.

Core claim

By separating algorithmic, computational, and representational advantage and tying each to concrete quantum primitives, the authors identify explicit cases in which quantum methods can address the sign problem, real-time dynamics, and sparse-data inference that arise when reconstructing CFFs, GPDs, TMDs, and GTMDs from Euclidean or experimental inputs. The central claim is that these observables constitute natural quantum targets precisely because their defining correlation functions lead to ill-posed inverse problems under classical approaches, and that credible advantage claims require real-device execution together with benchmark criteria.

What carries the argument

The tripartite classification of advantage—algorithmic (Hamiltonian simulation and amplitude estimation for real-time or sign-problematic observables), computational (direct quantum evaluation of matrix elements and correlators), and representational (quantum deep neural networks supplying physics priors in hybrid fits)—applied to the light-front and off-forward correlation functions that define the four classes of distributions.

If this is right

  • Hamiltonian simulation and amplitude estimation become applicable to real-time and sign-problematic observables that are otherwise inaccessible.
  • Direct quantum evaluation of matrix elements becomes plausible for PDFs, GPDs, timelike response functions, and high-energy evolution kernels.
  • Quantum deep neural networks can improve CFF extraction performance in noisy and sparse data regimes.
  • Hybrid fits become viable in which a quantum simulator supplies a physics prior while a classical network accounts for detector and nuisance effects.
  • Benchmark criteria must be established to make credible claims of quantum advantage in hadronic tomography.

Where Pith is reading between the lines

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

  • The same selective, observable-by-observable strategy could be used to rank quantum resources across other inverse problems in quantum field theory.
  • Current hardware milestones could be used to set quantitative timelines for when hybrid quantum-classical pipelines become competitive for nucleon-structure analyses.
  • The emphasis on real-device validation implies that lattice QCD programs might usefully incorporate quantum-assisted correlator evaluations as an additional cross-check.

Load-bearing premise

Quantum primitives such as Hamiltonian simulation, linear-response algorithms, amplitude estimation, and quantum deep neural networks will deliver practical gains over classical methods for these specific observables once real-device execution becomes feasible.

What would settle it

A side-by-side comparison, on identical input data, of reconstruction error and resource cost for a chosen Compton form factor or GPD when the extraction is performed with a quantum primitive on actual hardware versus with leading classical methods.

read the original abstract

We recast the case for quantum advantage in hadronic physics as an observable-by-observable question rather than a blanket claim about Quantum Chromo-Dynamics (QCD). Focusing on hadronic tomography, we analyze why Compton form factors (CFF), generalized parton distributions (GPDs), Transverse Momentum-dependent Distributions (TMDs), and Generalized Transverse Momentum-dependent Distributions (GTMDs) are natural quantum targets: they are defined by light-front, off-forward, or real-time correlation functions whose extraction from Euclidean calculations or sparse experimental data is often an ill-posed inverse problem. We separate three notions of advantage -- algorithmic, computational, and representational -- and connect each to explicit formal objects. At the algorithmic level, Hamiltonian simulation, linear-response algorithms, and amplitude-estimation primitives motivate gains for real-time and sign-problematic observables. At the computational level, direct quantum evaluation of matrix elements and correlators becomes plausible for PDFs, GPDs, timelike response, and high-energy evolution. At the inference level, recent Quantum Deep Neural Network (QDNN) studies of CFF extraction indicate improved performance in noisy and sparse regimes and motivate hybrid fits in which a quantum simulator supplies a physics prior while a classical network models detector and nuisance effects. We discuss why real-device execution is scientifically necessary, summarize current hardware milestones, and propose benchmark criteria for credible claims of quantum advantage in hadronic tomography.

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 / 3 minor

Summary. The manuscript recasts the case for quantum advantage in hadronic physics as an observable-by-observable question rather than a blanket claim about QCD. Focusing on hadronic tomography, it argues that Compton form factors (CFF), generalized parton distributions (GPDs), transverse-momentum dependent distributions (TMDs), and generalized TMDs (GTMDs) are natural quantum targets because they are defined by light-front, off-forward, or real-time correlation functions whose extraction from Euclidean lattice QCD or sparse experimental data constitutes an ill-posed inverse problem. The paper separates three notions of advantage (algorithmic, computational, and representational) and connects each to quantum primitives such as Hamiltonian simulation, linear-response algorithms, amplitude estimation, and quantum deep neural networks (QDNNs). It discusses the necessity of real-device execution, summarizes current hardware milestones, and proposes benchmark criteria for credible claims of quantum advantage.

Significance. If the perspective is adopted, it supplies a useful organizing framework for targeting quantum resources at specific hadronic observables rather than pursuing generic QCD simulations. The explicit separation of algorithmic, computational, and representational advantages, together with the call for falsifiable benchmarks and hybrid quantum-classical inference, provides a constructive roadmap that could help the community avoid overbroad claims. The linkage of standard quantum primitives to the sign-problem and inverse-problem challenges in GPD/TMD extraction is a clear strength of the presentation.

major comments (1)
  1. Abstract: The statement that 'recent Quantum Deep Neural Network (QDNN) studies of CFF extraction indicate improved performance in noisy and sparse regimes' is presented without citation, quantitative metrics, or even a brief summary of the reported gains. Because this claim is used to motivate the representational/inference-level advantage, it is load-bearing and requires substantiation.
minor comments (3)
  1. The title promises 'explicit cases' from CFFs, GPDs, TMDs, and GTMDs, yet the manuscript supplies only conceptual linkages; a short table or enumerated list mapping each observable to a concrete quantum primitive and the corresponding advantage type would make the central argument more actionable.
  2. The distinction between 'computational' and 'representational' advantage is introduced but not illustrated with a side-by-side comparison for any single observable; adding one worked example would sharpen the three-way taxonomy.
  3. The proposed benchmark criteria for quantum advantage are described at a high level; specifying at least one quantitative threshold (e.g., a target reduction in uncertainty or runtime scaling) would render the criteria falsifiable.

Simulated Author's Rebuttal

1 responses · 0 unresolved

We thank the referee for the positive assessment of the manuscript and the recommendation for minor revision. The single major comment is addressed point-by-point below.

read point-by-point responses
  1. Referee: Abstract: The statement that 'recent Quantum Deep Neural Network (QDNN) studies of CFF extraction indicate improved performance in noisy and sparse regimes' is presented without citation, quantitative metrics, or even a brief summary of the reported gains. Because this claim is used to motivate the representational/inference-level advantage, it is load-bearing and requires substantiation.

    Authors: We agree that the abstract statement requires substantiation, as it is used to motivate the inference-level advantage. In the revised version we will insert a specific citation to the relevant QDNN study on CFF extraction together with a concise clause summarizing the reported performance gains in noisy and sparse regimes. This addition will be kept brief to preserve abstract length while making the claim self-contained. revision: yes

Circularity Check

0 steps flagged

No significant circularity identified

full rationale

The manuscript is a perspective and proposal article. It motivates quantum approaches for CFF, GPDs, TMDs, and GTMDs by linking their light-front/off-forward/real-time definitions to known ill-posed inverse problems in Euclidean lattice QCD and sparse data extraction. No derivations, equations, quantitative predictions, or fitted parameters are advanced. The three notions of advantage are connected to standard quantum primitives (Hamiltonian simulation, amplitude estimation, QDNN) without any reduction to self-definition or self-citation chains. Prior QDNN references serve only as contextual motivation for hybrid fits and do not bear the load of any claimed result.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

No free parameters, axioms, or invented entities are introduced; the work is a conceptual reframing based on standard notions of inverse problems and quantum primitives.

pith-pipeline@v0.9.0 · 5566 in / 1311 out tokens · 71122 ms · 2026-05-10T16:42:14.512788+00:00 · methodology

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Reference graph

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