Nuclear Theory·nucl-th

Tuesday·May 21, 2024

15 papers—10 primary·5 cross-listed

11
[Submitted on 17 May 2024] (cross-list from cond-mat.mtrl-sci)
Magnetic Weyl semimetals as a source of circularly polarized THz radiation
Jeremy Hansen · Kazuki Ikeda · Dmitri E. Kharzeev · Qiang Li · Kirill Tuchin
We propose to use the electromagnetic radiation induced by a few MeV electron beam in magnetic Weyl semimetals as a source of the circularly polarized photons in the THz frequency range.
Subjects:
cond-mat.mtrl-sci (cond-mat.mtrl-sci); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2405.11076 [pdf]
Phys.Open(2025)·7 citations
12
[Submitted on 18 May 2024] (cross-list from hep-ph)
Revisiting $O (N)$ $σ$ model at unphysical pion masses and high temperatures. II. The vacuum structure and thermal $σ$ pole trajectory with cross-channel improvements
Yuan-Lin Lyu🇨🇳 · Qu-Zhi Li🇨🇳 · Zhiguang Xiao🇨🇳 · Han-Qing Zheng🇨🇳
The effective potential of the $O (N)$ model at large $N$ limit is reinvestigated with varying pion mass and temperature. For large pion masses and high temperatures, we find the phenomenologically favored vacuum, located on the upper branch of the double-branched effective potential for physical $m_{π}$ , moves to the lower branch and becomes no longer a local minimum but a saddle point. The existence and running of the tachyon pole are also discussed. These phenomena indicate that the applicable energy range of $O (N)$ model is more and more limited as $m_{π}$ becoming larger and temperature going higher. With the effective coupling constant defined from the effective potential, the possible correspondence between the two branches of the effective potential and the two phases of the theory (distinguished by positive or negative coupling) is verified even with nonzero explicit symmetry breaking and at finite temperature. Also, we generalize the $N / D$ modified $O (N)$ model to study the thermal trajectory of the $σ$ pole with the cross-channel contributions considered and find the thermal $σ$ pole trajectory resembles its counterpart with varying pion mass at zero temperature.
Comments:
v1: 15 pages, 14 figures; v2: 17 pages, 14 figures, references and some details added; v3: 18 pages, 16 figures, published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2405.11313 [pdf]
PRD(2024)·5 citations
13
[Submitted on 20 May 2024] (cross-list from astro-ph.HE)
Magnetar QPOs and neutron star crust elasticity
Hajime Sotani
The crust region is a tiny fraction of neutron stars, but it has a variety of physical properties and plays an important role in astronomical observations. One of the properties characterizing the crust is the elasticity. In this review, with the approach of asteroseismology, we systematically examine neutron star oscillations excited by crust elasticity, adopting the Cowling approximation. In particular, by identifying the quasi-periodic oscillations observed in magnetar flares with the torsional oscillations, we make a constraint on the nuclear saturation parameters. In addition, we also discuss how the shear and interface modes depend on the neutron star properties. Once one detects an additional signal associated with neutron star oscillations, one can get a more severe constraint on the saturation parameters and/or neutron star properties, which must be a qualitatively different constraint obtained from terrestrial experiments, and help us to complementarily understand astrophysics and nuclear physics.
Comments:
Accepted for publication in Universe: Feature Papers 2024 - Compact Objects
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2405.11858 [pdf]
Universe(2024)·19 citations
14
[Submitted on 20 May 2024] (cross-list from hep-ph)
Pole structure of $P_{ψ}^{N} (4312)^{+}$ via machine learning and uniformized S-matrix
Leonarc Michelle Santos🇵🇭 · Vince Angelo A. Chavez🇵🇭 · Denny Lane B. Sombillo🇵🇭
We probed the pole structure of the $P_{ψ}^{N} (4312)^{+}$ using a trained deep neural network. The training dataset was generated using uniformized independent S-matrix poles to ensure that the obtained interpretation is as model-independent as possible. To prevent possible ambiguity in the interpretation of the pole structure, we included the contribution from the off-diagonal element of the S-matrix. Five out of the six neural networks we trained favor $P_{ψ}^{N} (4312)^{+}$ as possibly having a three-pole structure, with one pole on each of the unphysical sheets - a first in its report. The two poles can be associated to a pole-shadow pair which is a characteristic of a true resonance. On the other hand, the last pole is most likely associated with the coupled-channel effect. The combined effect of these poles produced a peak below the $Σ_{C}^{+} D ˉ^{0}$ which mimic the line shape of a hadronic molecule.
Comments:
11 pages, 4 figures, 7 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2405.11906 [pdf]
J.Phys.G(2025)·13 citations
15
[Submitted on 20 May 2024] (cross-list from gr-qc)
Micro-cosmos model of a nucleon
Michael Cramer Andersen🇩🇰
This study explores the age-old quest to construct a geometric model of a quantum particle. While static classical particle models have largely been dismissed, the focus has now shifted to intricate dynamic models that hold the promise of reconciling general relativity with quantum mechanics. We propose that matter particles can be described as radiation confined within dynamically curved spacetime regions, without the need for quantization of space and time, and using standard field equations and natural Planck units. Specifically, we investigate a cyclic or oscillating radiation-dominated micro cosmos undergoing repeated bouncing. Our methodology employs integration, with carefully defined initial conditions. The results include several observable properties characteristic of quantum particles. We calculate the total mass, revealing a compelling inverse proportionality between mass and radius identical with the de Broglie relationship. Applying this model to protons, we discover a profound and surprisingly simple relationship between the proton's radius and mass expressed in Planck units. This enables a definition of the proton radius that aligns remarkably well with the 2018 CODATA value. Furthermore, our analysis demonstrates that the radial density profile of the proton (or nucleon), averaged over a cycle time, increases toward the center. The problem of embedding the micro cosmos within a background spacetime is also described. These results underscore the relevance of general relativity in the domain of nuclear physics. Moreover, the model offers a fresh perspective that can stimulate new ideas in the ongoing quest to unify general relativity with quantum physics.
Comments:
18 pages, 5 figures
Subjects:
General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
arXiv:
2405.12049 [pdf]
Mod.Phys.Lett.A(2024)·0 citations

Affiliations

first authorsco-authorsvia INSPIRE

Magnetic Weyl semimetals as a source of circularly polarized THz radiation

Revisiting O(N) σ model at unphysical pion masses and high temperatures. II. The vacuum structure and thermal σ pole trajectory with cross-channel improvements

Magnetar QPOs and neutron star crust elasticity

Pole structure of PψN​(4312)+ via machine learning and uniformized S-matrix

Micro-cosmos model of a nucleon

Affiliations

Revisiting $O (N)$ $σ$ model at unphysical pion masses and high temperatures. II. The vacuum structure and thermal $σ$ pole trajectory with cross-channel improvements

Pole structure of $P_{ψ}^{N} (4312)^{+}$ via machine learning and uniformized S-matrix