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7 pages, 292 KB

Open AccessProceeding Paper

New Contribution to the Anomalous π⁰→γγ Decay in SU(2) Chiral Perturbation Theory

by Zhen-Yan Lu, Shu-Peng Wang and Qi Lu

Proceedings 2025, 123(1), 1; https://doi.org/10.3390/proceedings2025123001 - 28 Jul 2025

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The introduction of axions gives rise to additional one-loop diagrams for the two-photon decays of neutral pions via axion-pion mixing. We compute this correction that has been overlooked in existing calculations, within the framework of SU(2) chiral perturbation theory. Our analysis shows that [...] Read more.

The introduction of axions gives rise to additional one-loop diagrams for the two-photon decays of neutral pions via axion-pion mixing. We compute this correction that has been overlooked in existing calculations, within the framework of SU(2) chiral perturbation theory. Our analysis shows that the correction is proportional to the axion-photon coupling and the square of the axion mass. In the classical axion parameter space, this correction is strongly suppressed by the axion decay constant. However, for QCD axions in the MeV or higher mass range, the correction may become significant. Furthermore, when combined with experimental measurements of the decay width of the

π^{0} \to γ γ

process, our results rule out the standard QCD axion as a viable explanation for the observed discrepancy between chiral perturbation theory predictions and experimental data. Full article

(This article belongs to the Proceedings of The 5th International Conference on Symmetry (Symmetry 2025))

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7 pages, 263 KB

Open AccessProceeding Paper

Recent Progress on Conjecture

O

and Its Variants: A Survey

by Xiaobin Li, Yuhui Peng, Yamin Xu and Bin Zhu

Proceedings 2025, 123(1), 2; https://doi.org/10.3390/proceedings2025123002 - 28 Jul 2025

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Abstract

Conjecture

O

(and the Gamma Conjectures), introduced by Galkin, Golyshev, and Iritani stand as pivotal open problems in the quantum cohomology of Fano manifolds, bridging algebraic geometry, mathematical physics, and representation theory. These conjectures aim to decode the structural essence of quantum multiplication [...] Read more.

Conjecture

O

(and the Gamma Conjectures), introduced by Galkin, Golyshev, and Iritani stand as pivotal open problems in the quantum cohomology of Fano manifolds, bridging algebraic geometry, mathematical physics, and representation theory. These conjectures aim to decode the structural essence of quantum multiplication by uncovering profound connections between spectral properties of quantum cohomology operators and the underlying geometry of Fano manifolds. Conjecture

O

specifically investigates the spectral simplicity and eigenvalue distribution of the operator associated with the first Chern class

c_{1}

in quantum cohomology rings, positing that its eigenvalues govern the convergence and asymptotic behavior of quantum products. Full article

(This article belongs to the Proceedings of The 5th International Conference on Symmetry (Symmetry 2025))

8 pages, 306 KB

Open AccessProceeding Paper

Constraints on the Equation of State of Quark Stars from Compact Object Observations

by Shu-Peng Wang, Zhi-Jun Ma, Jian-Feng Xu and Zhen-Yan Lu

Proceedings 2025, 123(1), 3; https://doi.org/10.3390/proceedings2025123003 - 29 Jul 2025

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Abstract

Introducing an additional term into the thermodynamic potential density of the quark matter system, as required for thermodynamic consistency, resolves the inconsistency that arises in the conventional perturbative quantum chromodynamics (QCD) model. In this work, we use a revised, thermodynamically consistent perturbative QCD [...] Read more.

Introducing an additional term into the thermodynamic potential density of the quark matter system, as required for thermodynamic consistency, resolves the inconsistency that arises in the conventional perturbative quantum chromodynamics (QCD) model. In this work, we use a revised, thermodynamically consistent perturbative QCD model to compute the stability window and equation of state of up-down (

u d

) quark matter at zero temperature. Our results indicate that the measured tidal deformability for GW170817 places an upper limit on the maximum mass of

u d

quark stars, but does not rule out the possibility of such stars with a mass of about two solar masses. However, when the maximum mass of

u d

quark stars significantly exceeds two solar masses, such as the compact object with a mass in the range of 2.50–2.67

M_{⊙}

observed in the GW190814 event, it cannot be identified as a

u d

quark star according to the revised perturbative QCD model. Full article

(This article belongs to the Proceedings of The 5th International Conference on Symmetry (Symmetry 2025))

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8 pages, 514 KB

Open AccessProceeding Paper

The QCD Axion in Hot and Dense Matter

by Hong-Fang Gong, Qi Lu and Zhen-Yan Lu

Proceedings 2025, 123(1), 4; https://doi.org/10.3390/proceedings2025123004 - 8 Sep 2025

Viewed by 1820

Abstract

Within the framework of the two-flavor Nambu–Jona-Lasinio model, we study the quantum chromodynamics axion properties at finite temperature and chemical potential. Our analysis shows that the axion properties are strongly influenced by the critical behavior of the chiral phase transition. In particular, the [...] Read more.

Within the framework of the two-flavor Nambu–Jona-Lasinio model, we study the quantum chromodynamics axion properties at finite temperature and chemical potential. Our analysis shows that the axion properties are strongly influenced by the critical behavior of the chiral phase transition. In particular, the axion mass follows the response of the chiral condensate to temperature and chemical potential, decreasing monotonically as either parameter increases. Moreover, we observe that at relatively low temperatures, the axion self-coupling constant exhibits a sharp peak near the critical point when the chemical potential increases, reaching more than twice its vacuum value. Beyond the critical point, the self-coupling rapidly decreases to values much smaller than in vacuum, eventually approaching zero at high chemical potential. These results suggest that the significant enhancement of the axion self-coupling in dense matter near the chiral phase transition may favor the formation or amplification of an axion Bose–Einstein condensate in compact astrophysical objects. Full article

(This article belongs to the Proceedings of The 5th International Conference on Symmetry (Symmetry 2025))

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13 pages, 497 KB

Open AccessProceeding Paper

Symmetries and Scale Invariance in Global Maps of Quantum Circuits

by Theophanes Raptis and Vasilios Raptis

Proceedings 2025, 123(1), 5; https://doi.org/10.3390/proceedings2025123005 - 9 Sep 2025

Viewed by 1753

Abstract

We present a combinatorial analysis of any maximal set of gate compositions parameterized over a finite alphabet which revealed an underlying fractal structure. Results are presented as global maps in the form of large 2D arrays where each row stands for an unfolded [...] Read more.

We present a combinatorial analysis of any maximal set of gate compositions parameterized over a finite alphabet which revealed an underlying fractal structure. Results are presented as global maps in the form of large 2D arrays where each row stands for an unfolded list of matrix elements for any unitary matrix resulting from a succession of Kronecker products while columns stand for all possible words representing such sequences. These can be given either in lexicographic order or via a non-binary (n-ary) Gray code in which case any such map can be factorized. Full article

(This article belongs to the Proceedings of The 5th International Conference on Symmetry (Symmetry 2025))

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9 pages, 1461 KB

Open AccessProceeding Paper

Chemical Equitable Partitions: A New Perspective on Molecular Symmetries and Its Implications for the Study of Structure–Property Relationships

by Vasilios Raptis and Ioannis Michos

Proceedings 2025, 123(1), 6; https://doi.org/10.3390/proceedings2025123006 - 12 Sep 2025

Viewed by 238

Abstract

In this work, the concept of equitable partition is applied to molecular graphs to define quantitative descriptors of the symmetry and complexity of molecules, with the ultimate goal of shedding new light on the structure–property relationships of chemical compounds and materials. The ways [...] Read more.

In this work, the concept of equitable partition is applied to molecular graphs to define quantitative descriptors of the symmetry and complexity of molecules, with the ultimate goal of shedding new light on the structure–property relationships of chemical compounds and materials. The ways in which symmetry is reflected in these descriptors and their correlations with molecular properties are demonstrated using simple examples, and their potential for the prediction of properties of complex molecules is underscored. Full article

(This article belongs to the Proceedings of The 5th International Conference on Symmetry (Symmetry 2025))

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7 pages, 1395 KB

Open AccessProceeding Paper

Exact Solutions of the (2+1)-Dimensional Generalized Burgers–Fisher Equation via Lie Symmetry and Generalized Bernoulli Method

by Yu-Xiang Li and Yu-Shan Bai

Proceedings 2025, 123(1), 7; https://doi.org/10.3390/proceedings2025123007 - 17 Sep 2025

Viewed by 139

Abstract

This paper systematically studies the exact analytical solutions of the (2+1)-dimensional generalized Burgers–Fisher (gBF) equation. Using the Lie symmetry analysis method, the infinitesimal generators of the equation are derived. Through symmetry reduction, the original (2+1)-dimensional partial differential equation (PDE) is reduced to a [...] Read more.

This paper systematically studies the exact analytical solutions of the (2+1)-dimensional generalized Burgers–Fisher (gBF) equation. Using the Lie symmetry analysis method, the infinitesimal generators of the equation are derived. Through symmetry reduction, the original (2+1)-dimensional partial differential equation (PDE) is reduced to a (1+1)-dimensional equation, which is further transformed into an ordinary differential equation (ODE) via the traveling wave transformation. On this basis, a series of exact traveling wave solutions are successfully obtained by applying the generalized Bernoulli equation method, including hyperbolic tangent-type kink solitary wave solutions and hyperbolic cotangent-type singular soliton solutions. The study also conducts a visual analysis of the solution characteristics through three-dimensional graphs and contour plots. In particular, this paper discusses the case where the parameter n takes general values, filling the research gap in the existing literature. Full article

(This article belongs to the Proceedings of The 5th International Conference on Symmetry (Symmetry 2025))

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