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  • Letter
  • Open Access

Entanglement, trace anomaly, and confinement in QCD

Kiminad A. Mamo*

  • *Contact author: kamamo@wm.edu, kamamo@jlab.org
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Phys. Rev. D 112, L111506 – Published 17 December, 2025

DOI: https://doi.org/10.1103/rphx-65x9

Abstract

We formulate confinement in quantum chromodynamics (QCD) as an entropic surface phenomenon. Quark and gluon quantum information is localized on a transverse, entangling two-sphere of radius REE; at this radius the QCD vacuum—partitioned by a hadron into interior and exterior regions—reaches its maximal entanglement entropy. Lattice-QCD determinations of the scalar (trace) gravitational form factors fix both REE and the transverse trace-anomaly density ρh(REE), yielding a parameter-free slope ch=8π2REE2ρh(REE) and a mechanical entropy SEE(y)=chy that grows linearly with rapidity y. The entropy gradient ∂RSEE changes sign at REE: it pushes colored degrees of freedom outward for r<REE and pulls them inward for r>REE, thereby localizing them on the codimension-2 entangling two-sphere Σ⊥=SREE2 (which, in the infinite-momentum frame (IMF), projects onto the transverse plane)—the “information wall.” This provides a high-energy (large-y) entropic confinement diagnostic that complements—rather than replaces—Wilson’s area-law criterion, which probes long-distance dynamics near the rest frame (y→0). Imposing unitarity on an entropic ansatz for the amplitude yields σ(s)∝yδ. World data favor δ=2 for elastic pp(pp¯) scattering and heavy-quark photoproduction, whereas ϕ photoproduction favors a softer δ=0.387. All extracted cross sections remain well below the Froissart-Martin bound. These results provide a confinement criterion quantified directly from nonperturbative QCD inputs, unifying the trace anomaly, entanglement entropy, and high-energy scattering within a single quantitative framework.

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Phys. Rev. D 112, L111506– Published 17 December, 2025
  • Received 10 July 2025
  • Accepted 15 November 2025
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