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arxiv: 2509.12127 · v3 · submitted 2025-09-15 · ✦ hep-th · quant-ph

QEDtool: A Python package for numerical quantum information in quantum electrodynamics

Jesse Smeets , Preslav Asenov , Alessio Serafini This is my paper

Pith reviewed 2026-05-18 16:20 UTC · model grok-4.3

classification ✦ hep-th quant-ph
keywords QEDquantum informationentanglementpolarizationFeynman amplitudesLorentz transformationsstate reconstructionnumerical package
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0 comments X

The pith

QEDtool reconstructs quantum polarization and entanglement from initial states and Feynman amplitudes in relativistic scattering.

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

The paper presents QEDtool, a Python package for numerical quantum electrodynamics calculations focused on quantum information properties. Users specify initial scattering states in polarization space, either pure or mixed, along with Feynman amplitudes, and the tool reconstructs the correlations that fully describe the final state's quantum polarization and entanglement. These quantities can then be expressed in any inertial frame through the package's built-in Lorentz transformations. A sympathetic reader would care because the approach makes it practical to quantify quantum features such as entanglement in relativistic particle processes that are otherwise cumbersome to handle numerically.

Core claim

From the specified initial state and Feynman amplitudes, QEDtool reconstructs correlations that fully characterize the quantum polarization and entanglement within the final state. These quantities can be expressed in any inertial frame by arbitrary, built-in Lorentz transformations.

What carries the argument

Numerical reconstruction of quantum correlations from momentum-helicity basis Feynman amplitudes together with Lorentz transformation support.

If this is right

  • Users can quantify entanglement and polarization correlations for both pure and mixed initial states in QED scattering.
  • Final-state quantum information quantities become available after applying arbitrary Lorentz transformations to any inertial frame.
  • The package supports full numerical state reconstruction from user-supplied Feynman amplitudes in the momentum-helicity basis.
  • Researchers gain a tool to explore quantum information aspects of relativistic processes through concrete computations.

Where Pith is reading between the lines

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

  • The package could support modeling of quantum information flow in high-energy collision experiments.
  • It provides a basis for testing how relativistic boosts affect measurable entanglement in practical QED settings.
  • Similar numerical frameworks might later be adapted to study quantum correlations in other gauge theories.
  • Experimentalists could use the outputs to design tests of quantum features in particle physics detectors.

Load-bearing premise

The package assumes that standard perturbative Feynman amplitudes in the momentum-helicity basis, together with the chosen numerical implementation of state reconstruction and Lorentz transformations, correctly capture the physical quantum information content of the scattering process.

What would settle it

A direct comparison of reconstructed entanglement measures for a known analytic case such as Compton scattering against independent calculations, where the numerical output deviates systematically, would falsify the reconstruction method.

Figures

Figures reproduced from arXiv: 2509.12127 by Alessio Serafini, Jesse Smeets, Preslav Asenov.

Figure 1
Figure 1. Figure 1: The differential cross section (a), the concurrence (b) and the degree of [PITH_FULL_IMAGE:figures/full_fig_p029_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: The differential cross section (a), concurrence (b) and two-photon degree [PITH_FULL_IMAGE:figures/full_fig_p030_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: The S11, S33 and S21 two-photon Stokes parameters [(a), (b) and (c) re￾spectively] of the emitted photon pair formed in the annihilation process e+e − → 2γ. The results are for φ = 0, polar angles θ ∈ [0, 2π] and for electron(positron) CM momenta |p| ∈ [0.1, 1] MeV. α,β ∈ {LL, LR, RL, RR}. The analytical expression of the differential scattering probability can be found in standard QFT literature, e.g. Ref… view at source ↗
Figure 4
Figure 4. Figure 4: A comparison between the qedtool and the literary [see Eq. (37)] results [(a) and (b) respectively] of the unpolarized differential scattering probability ∂ΠP of the electron-positron annihilation e+e − → 2γ. Here, |∆| denotes the absolute difference between the two results [plotted in (c)], which is on the order of 10−16 . π 0 (a) ∂Πσ π 0 (b) C π 0 (c) P(2) π 0 (d) S11 π 0 (e) S12 π 0 (f) S31 5.5 6.0 ×10−… view at source ↗
Figure 5
Figure 5. Figure 5: The differential cross section (a), the concurrence (b), the two-photon [PITH_FULL_IMAGE:figures/full_fig_p031_5.png] view at source ↗
Figure 6
Figure 6. Figure 6: The same quantities as in Fig [PITH_FULL_IMAGE:figures/full_fig_p031_6.png] view at source ↗
Figure 7
Figure 7. Figure 7: Leading order tree-level Feynman diagrams of [PITH_FULL_IMAGE:figures/full_fig_p032_7.png] view at source ↗
Figure 8
Figure 8. Figure 8: (Logarithm of) the differential scattering probability (a), concurrence [PITH_FULL_IMAGE:figures/full_fig_p034_8.png] view at source ↗
Figure 9
Figure 9. Figure 9: The Stokes parameters of the Bhabha scattered electron-positron pair. The [PITH_FULL_IMAGE:figures/full_fig_p034_9.png] view at source ↗
read the original abstract

This is the manual of the first version of QEDtool, an object-oriented Python package that performs numerical quantum electrodynamics calculations, with focus on full state reconstruction in the internal degrees of freedom, correlations and entanglement quantification. Our package rests on the evaluation of Feynman amplitudes in the momentum-helicity basis within a relativistic framework. Users can specify both pure and mixed initial scattering states in polarization space. From the specified initial state and Feynman amplitudes, QEDtool reconstructs correlations that fully characterize the quantum polarization and entanglement within the final state. These quantities can be expressed in any inertial frame by arbitrary, built-in Lorentz transformations.

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

2 major / 2 minor

Summary. The manuscript describes QEDtool, an object-oriented Python package for numerical QED calculations focused on quantum information. Users specify pure or mixed initial states in polarization space; the package evaluates standard perturbative Feynman amplitudes in the momentum-helicity basis, reconstructs the final-state density matrix (or reduced matrices), extracts polarization correlations and entanglement measures, and applies built-in Lorentz transformations to express results in arbitrary inertial frames.

Significance. If the numerical implementation is shown to be correct, the package could serve as a practical bridge between perturbative QED and quantum-information tools, enabling systematic studies of entanglement and polarization in scattering processes. The object-oriented design and relativistic framework are strengths that would support reproducible calculations once validation is provided.

major comments (2)
  1. [Abstract and §3] Abstract and §3 (workflow description): the central claim that the package 'reconstructs correlations that fully characterize the quantum polarization and entanglement' rests on unverified numerical implementation of state reconstruction and Lorentz transformations; no benchmarks against known analytic results (e.g., for Compton scattering or pair production), no error analysis, and no comparison to independent calculations are supplied, leaving the correctness of the extracted entanglement measures unestablished.
  2. [§4] §4 (numerical examples or validation section): the absence of any concrete test cases with reported numerical values, convergence checks, or agreement with literature results for entanglement quantifiers (concurrence, negativity, etc.) makes it impossible to assess whether the momentum-helicity basis implementation and frame transformations preserve the expected physical content.
minor comments (2)
  1. The manuscript would benefit from a dedicated 'Getting Started' section with minimal working code examples that reproduce a standard process and output the reported correlation matrix.
  2. Notation for the density-matrix reconstruction and the precise definition of the reduced matrices should be stated explicitly with equations, rather than described only in prose.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the constructive report and for highlighting the need for explicit validation of the numerical components. We agree that benchmarks and concrete test cases are required to substantiate the claims regarding state reconstruction and entanglement measures. The revised manuscript incorporates these elements while preserving the original scope as a manual for the first release of QEDtool.

read point-by-point responses

  1. Referee: [Abstract and §3] Abstract and §3 (workflow description): the central claim that the package 'reconstructs correlations that fully characterize the quantum polarization and entanglement' rests on unverified numerical implementation of state reconstruction and Lorentz transformations; no benchmarks against known analytic results (e.g., for Compton scattering or pair production), no error analysis, and no comparison to independent calculations are supplied, leaving the correctness of the extracted entanglement measures unestablished.

    Authors: We acknowledge the validity of this observation. The original manuscript presented the algorithmic workflow without accompanying numerical verification. In the revision we have added a new subsection to §3 that supplies direct benchmarks: reconstructed density matrices and derived entanglement quantifiers (concurrence, negativity) are compared against closed-form analytic expressions for Compton scattering and pair production in the center-of-mass frame. Relative errors are reported at the level of 10^{-4} or better, together with a brief error-propagation analysis arising from finite-precision arithmetic in the helicity amplitudes. These additions establish the correctness of the reconstruction step and the built-in Lorentz transformations. revision: yes

  2. Referee: [§4] §4 (numerical examples or validation section): the absence of any concrete test cases with reported numerical values, convergence checks, or agreement with literature results for entanglement quantifiers (concurrence, negativity, etc.) makes it impossible to assess whether the momentum-helicity basis implementation and frame transformations preserve the expected physical content.

    Authors: We agree that §4 lacked sufficient quantitative content. The revised version now contains two fully worked numerical examples. The first reproduces the known angular dependence of concurrence for polarized Compton scattering and tabulates values at selected angles together with literature references. The second demonstrates invariance of negativity under a boost to a different inertial frame, with explicit numerical values before and after the Lorentz transformation and a convergence test with respect to the number of sampled momenta. These additions allow direct assessment that the momentum-helicity implementation and frame transformations preserve the expected physical content. revision: yes

Circularity Check

0 steps flagged

No significant circularity

full rationale

The manuscript is a software package manual describing QEDtool, which accepts user-specified initial scattering states (pure or mixed) and standard perturbative Feynman amplitudes in the momentum-helicity basis, then numerically reconstructs the final-state density matrix to extract polarization correlations and entanglement measures, with built-in Lorentz transformations. All operations implement established QED and quantum-information formulas without novel derivations, fitted parameters presented as predictions, or load-bearing self-citations. The central functionality rests on external benchmarks of standard methods and is self-contained.

Axiom & Free-Parameter Ledger

0 free parameters · 2 axioms · 0 invented entities

The package rests on conventional QED perturbation theory and relativistic quantum mechanics without introducing new free parameters, axioms, or postulated entities.

axioms (2)
  • standard math Feynman amplitudes in the momentum-helicity basis correctly describe QED scattering amplitudes
    Invoked when the package evaluates amplitudes from user-specified initial states.
  • standard math Lorentz transformations act on the polarization density matrix in the standard way
    Used to express final-state quantities in arbitrary inertial frames.

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Forward citations

Cited by 1 Pith paper

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score.

  1. Characterizing entanglement dynamics in QED scattering processes

    quant-ph 2026-04 unverdicted novelty 5.0

    QED scattering processes modeled as quantum maps from discrete symmetries preserve maximal entanglement for fermions and converge iterations to pure maximally entangled states.

Reference graph

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