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Nuclear Theory·nucl-th

Wednesday·April 23, 2025

10 papers—6 primary·4 cross-listed

All10Primary6Cross-lists4
  1. 07

    Compton Form Factor Extraction using Quantum Deep Neural Networks

    Brandon B. Le🇺🇸 · Dustin Keller🇺🇸

    We extract Compton form factors (CFFs) from deeply virtual Compton scattering measurements at the Thomas Jefferson National Accelerator Facility (JLab) using quantum-inspired deep neural networks (QDNNs). The analysis implements the twist-2 Belitsky-Kirchner-Müller formalism and employs a fitting strategy that emulates standard local fits. Using pseudodata, we benchmark QDNNs against classical deep neural networks (CDNNs) and find that QDNNs often deliver higher predictive accuracy and tighter uncertainties at comparable model complexity. Guided by these results, we introduce a quantitative selection metric that indicates when QDNNs or CDNNs are optimal for a given experimental fit. After obtaining local extractions from the JLab data, we perform a standard neural-network global CFF fit and compare with previous global analyses. The results support QDNNs as an efficient and complementary tool to CDNNs for CFF determination and for future multidimensional studies of parton distributions and hadronic structure.

    ↳ cs.LGhep-phnucl-thquant-phPRC(2026)·6 citations
  2. 08

    Coupled Instantons In A Four-Well Potential With Application To The Tunneling Of A Composite Particle

    Pervez Hoodbhoy · M. Haashir Ismail · M. Mufassir

    Coupled instantons are introduced by generalizing the double well potential to multiple mutually coupled wells. Physically this corresponds to the simultaneous tunneling of multiple degrees of freedom. A system with four equal minima is examined in detail. It has three instanton types or flavors with distinct actions. For weak coupling and subject to there being a single large (or small) parameter, the interactive system can be handled perturbatively. The zero mode problem arising from time translation symmetry is handled via the Fadeev-Popov procedure. A diagrammatic procedure allows corrections to the fluctuation determinant to be calculated systematically. Independent instanton contributions are summed over by extending the dilute gas approximation to three flavors and energy splittings of the lowest four states is calculated. All tunneling amplitudes are concisely expressed in terms of elementary functions. While the model is possibly useful for a variety of physical systems, an application is made here to the tunneling of a composite particle in one dimension.

    ↳ quant-phcond-mat.othermath-phmath.MP+10 citations
  3. 09

    On the Klein-Gordon bosonic fields in the Bonnor-Melvin spacetime with a cosmological constant in rainbow gravity: Bonnor-Melvin Domain Walls

    Omar Mustafa🇹🇷 · Abdullah Guvendi🇹🇷

    We investigate the effect of rainbow gravity on Klein-Gordon (KG) bosons in the background of the magnetized Bonnor-Melvin (BM) spacetime with a cosmological constant. We first show that the very existence of the sinusoidal term \(\sin^2(\sqrt{2\Lambda}r)\), in the BM space-time metric, suggests that \(\sin^2(\sqrt{2\Lambda}r) \in [0,1],\) which consequently restricts the range of the radial coordinate \(r\) to \(r \in [0,\pi/\sqrt{2\Lambda}]\). Moreover, we show that at \(r = 0\) and \(r = \pi/\sqrt{2\Lambda}\), the magnetized BM-spacetime introduces domain walls (infinitely impenetrable hard walls) within which the KG bosonic fields are allowed to move. Interestingly, the magnetized BM-spacetime introduces not only two domain walls but a series of domain walls. However, we focus on the range \(r \in [0,\pi/\sqrt{2\Lambda}]\). A quantum particle remains indefinitely confined within this range and cannot be found elsewhere. Based on these findings, we report the effects of rainbow gravity on KG bosonic fields in BM-spacetime. We use three pairs of rainbow functions: \( f(\chi) = \frac{1}{1 - \tilde{\beta} |E|}, \, h(\chi) = 1 \); \( f(\chi) = (1 - \tilde{\beta} |E|)^{-1}, \, h(\chi) = 1 \); and \( f(\chi) = 1, \, h(\chi) = \sqrt{1 - \tilde{\beta} |E|^\upsilon} \), with \(\upsilon = 1,2\). Here, \(\chi = |E| / E_p\), \(\tilde{\beta} = \beta / E_p\), and \(\beta\) is the rainbow parameter. We found that while the pairs \((f,h)\) in the first and third cases fully comply with the theory of rainbow gravity and ensure that \(E_p\) is the maximum possible energy for particles and antiparticles, the second pair does not show any response to the effects of rainbow gravity. We show that the corresponding bosonic states can form magnetized, spinning vortices in monolayer materials, and these vortices can be driven by adjusting an out-of-plane aligned magnetic field.

    ↳ gr-qcnucl-thEPJC(2025)·6 citations
  4. 10

    Spin structure of spin-1 charmonium states near

    HyungJoo Kim🇯🇵

    We investigate the spin structure of the and charmonium states near the critical temperature using QCD sum rules. To this end, we compute the contribution of the dimension-4 twist-2 gluon operator to the two-point function of heavy vector and axial vector currents in a rotating frame. As temperature increases, the quark spin contribution slightly increases, while the quark orbital angular momentum decreases by a comparable amount. The gluon contribution remains nearly unchanged. These thermal changes cancel each other, ensuring that the total spin is preserved even at finite temperature.

    ↳ hep-phnucl-th1 citation

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