We present an algorithm to extract the Coulomb branch Hasse diagram of orthosymplectic three-dimensional (3D) <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">N</mi><mo>=</mo><mn>4</mn></math> quiver gauge theories. The algorithm systematically predicts all descendant theories arising from Coulomb branch Higgsing, thereby detailing the stratification of the symplectic singularity defined by the initial Coulomb branch. Leveraging the Lie algebra isomorphism <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="fraktur">su</mi><mo stretchy="false">(</mo><mn>4</mn><mo stretchy="false">)</mo><mo>≅</mo><mi mathvariant="fraktur">so</mi><mo stretchy="false">(</mo><mn>6</mn><mo stretchy="false">)</mo></mrow></math>, we validate our algorithm via the 3D mirror of the 4D theories of class <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">S</mi></math> of such type. This comparison involves moduli spaces that admit both orthosymplectic and unitary quiver realizations, the latter being well understood via standard techniques such as decay and fission. Higgsing on the Coulomb branch of the 3D mirror or the magnetic quiver translates to Higgs branch renormalization group flows of the corresponding higher-dimensional superconformal field theories. Thus, we benchmark our method via Higgsing 6D <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">N</mi><mo>=</mo><mo stretchy="false">(</mo><mn>1</mn><mo>,</mo><mn>0</mn><mo stretchy="false">)</mo></math> D-type orbi-instanton theories, predicting novel Higgsing patterns involving products of interacting fixed points, and class <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">S</mi></math> theories of type <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="fraktur">so</mi><mo stretchy="false">(</mo><mn>2</mn><mi>N</mi><mo stretchy="false">)</mo></math>, demonstrating Higgsing to products of theories of types specified by Levi subalgebras of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="fraktur">so</mi><mo stretchy="false">(</mo><mn>2</mn><mi>N</mi><mo stretchy="false">)</mo></math>.

Germany

Craig Lawrie

Lorenzo Mansi

Austria

Marcus Sperling

United Kingdom

Zhenghao Zhong

Pathway to decay and fission of orthosymplectic quiver theories

A crossover involving three-fermion clusters is relevant to the hadron-quark crossover, which, if occurring in a neutron star, could naturally reproduce the dense-matter equation of state recently deduced from simultaneous observations of neutron-star masses and radii. To understand the crossover mechanism, we examine the role of tripling fluctuations induced by the formation of three-fermion clusters. The phase-shift representation of fluctuations manifests an interplay of bound and scattering states, leading to nonmonotonic momentum distributions of baryonlike clusters and peaked sound speed at finite densities. We demonstrate them by applying our approach to a nonrelativistic system of one-dimensional three-color fermions analogous to the hadron-quark matter.

Japan

Hiroyuki Tajima

Kei Iida

Toru Kojo

Haozhao Liang

Tripling Fluctuations and Peaked Sound Speed in Fermionic Matter

The Event Horizon Telescope (EHT) imaged black holes M87 $$^*$$ (angular diameter $$\theta _d = 42 \pm 3\,\upmu \text {as},$$ mass $$\sim 6.5 \times 10^9\,M_\odot )$$ and Sgr A $$^*$$ $$(\theta _d = 48.7 \pm 7\,\upmu \text {as},$$ shadow deviation $$\delta \approx -0.08^{+0.09}_{-0.09}$$ (VLTI), $$-0.04^{+0.09}_{-0.10})$$ (Keck). These observations enable tests of gravity in strong regimes. We propose a rotating non-commutative inspired Kiselev black hole (RNKBH), incorporating dark energy $$(\omega )$$ and non-commutative $$(\Theta )$$ parameters, extending Kerr solutions. Our analysis reveals that $$\omega = -2/3$$ allows larger $$\Theta $$ but requires $$a \ge 0.16M$$ to maintain horizons. Shadow calculations show significant deviations from Kerr predictions: for $$\Theta = 0.001-0.005M^2,$$ shadows shrink by 8-15% and distortion increases by 20-35% for rapidly spinning $$(a > 0.5M)$$ black holes. The $$\omega = -2/3$$ exhibits shadow squeezing near the cosmological horizon. We compute shadow observables and compare them with EHT data. For Sgr A $$^*$$ $$(50^\circ $$ inclination), the bounds are $$0.001497 \le \Theta \le 0.002868\,M^2$$ at $$a =0.9146$$ $$(\omega = -2/3)$$ . For M87 $$^*$$ $$(17^\circ )$$ , $$0 \le \Theta \le 0.004993 \,M^2$$ at $$a=0.0.6167$$ $$(\omega = -2/3)$$ . While EHT cannot yet distinguish RNKBH from Kerr BH, our results highlight its viability as an astrophysical candidate.

China

Fazlay Ahmed

India

Heena Ali

Qiang Wu

Tao Zhu

South Africa

Sushant Ghosh

Shadows of rotating non-commutative Kiselev black holes: constraints from EHT observations of M87* and Sgr A*

In this paper, we investigate a <math altimg='si1.svg'><mo stretchy='false'>(</mo><mn>1</mn><mo linebreak='badbreak' linebreakstyle='after'>+</mo><mn>3</mn><mo stretchy='false'>)</mo></math>-dimensional static Friedmann-Robertson-Walker (FRW) space-time, pierced by a cosmic string. Our analysis begins with a detail study of the geodesic motion of photon rays in this curved background, focusing on the behavior of the associated effective potential. This allows us to understand how the cosmic string and curvature of space-time influence the trajectories of light rays. Moving beyond ray optics, we explore wave optics by solving the covariant Helmholtz equation in this gravitational setting. By transforming the resulting radial equation into a Schr&#246;dinger-like form, we extract an effective potential and derive a frequency-dependent refractive index. This refractive index shows the combined effects of the cosmic string and the curvature parameter, showing their influence on the wave propagation. Furthermore, we extend our study to a <math altimg='si2.svg'><mo stretchy='false'>(</mo><mn>1</mn><mo linebreak='badbreak' linebreakstyle='after'>+</mo><mn>2</mn><mo stretchy='false'>)</mo></math>-dimensional space-time with disclinations, where we analyze the wave optics phenomena. Through the Helmholtz equation in this lower-dimensional case, we determine the refractive index and discuss how it is affected by the geometric parameters of this lower-dimensional space-time. Through both geometric and wave optics approaches, our work provides a comprehensive understanding of how topological defects and curvature impact geometric and physical optics in curved space-time of three- and four-dimensions.

Faizuddin Ahmed

Algeria

Abdelmalek Bouzenada

Ray and wave dynamics in a static FRW spacetime with conical singularity

We argue for the existence of bounds on the tensions of $\textit{p}$-branes in de Sitter space in terms of the Hubble rate and the strength of a class of Chern-Simons-like couplings. The world-volume couplings involve Abelian 1-form gauge fields in the bulk and possibly field strengths intrinsic to the brane. In many cases these couplings are the D-brane Chern-Simons terms present in string theory, while in other cases they are the interactions of axion domain walls with U(1) fields. Our arguments use the same logic and assumptions as the recent Festina Lente proposal (thus utilizing the properties of Nariai de Sitter black holes) and generalize it to extended objects, thereby providing a bottom-up set of constraints independent of any particular UV completion. We compare these bounds to the properties of (wrapped) D-branes in Type II string theory in the weak coupling limit, under the assumption that these properties are not modified significantly in de Sitter constructions. We find that all constraints are satisfied by D-branes, providing further evidence for the Festina Lente conjecture. For the particular case of 2-branes with Chern-Simons interactions we obtain a bound, which however can be evaded if the theory contains a light axion. Similarly, we find the bounds do not apply to axion domain walls due to the presence of the axion.

Saquib Hassan

Georges Obied

John March-Russell

De Sitter space constraints on brane tensions and couplings

In analogue gravity studies, the goal is to replicate black hole phenomena, such as Hawking radiation, within controlled laboratory settings. In the realm of condensed matter systems, this may happen in 2D tilted Dirac cone materials based on honeycomb lattices. In particular, we compute the entropy of this system, and find it has the same form as black hole Bekenstein-Hawking entropy, if an analogue horizon forms. Hence, these systems can be potential analogues of quantum black holes. We show that this entropy is primarily concentrated in the region where the tilt parameter is close to one, which corresponds to the location of the analogue black hole horizon. Additionally, when nonlinear effects are taken into account, the entropy is peaked in a small pocket of the Fermi sea that forms behind the analogue event horizon, which we call the $\textit{Fermi puddle}$. We further refer to this new type of analogue black hole as a $\textit{smart hole}$, since, in contrast to dumb holes, it can simulate both the correct temperature $\textit{and}$ entropy of general relativistic black holes. These results provide an opportunity to illuminate various quantum facets of black hole physics in a laboratory setting.

Canada

Jiayue Yang

Niayesh Afshordi

Mahdi Torabian

Seyed Jafari

G. Baskaran

Smart holes: analogue black holes with the right temperature and entropy

We discuss the dynamics of the quantum fluctuation around the nonlinear massive wave solution in the Higgs potential. In particular, we analyze the stability and instability of the mode function. Using the stability condition for Hill’s equation, we obtain the instability region of the mode function in the quantum fluctuation as the function of the parameters in the mode equation. We show that the two types of the instabilities of the system in the particle number can be understood by the Floquet’s exponents in the instability parameter region. The analysis will be useful to understand the dynamics of the quantum field theory around the nonlinear massive wave solution when the classical background slightly deviates from the constant background during the middle stage of the phase transition.

Taiwan

Yoshio Kitadono

Tomohiro Inagaki

Instability of quantum fluctuation around classical nonlinear massive wave solution in Higgs potential and particle creations

The pseudorapidity density distributions of charged particles and the transverse-momentum spectra of identified particles in proton-proton (<math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>p</mi><mi>p</mi></mrow></math>) collisions at the center-of-mass energies ranging from <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>200</mn></mrow></math> GeV to 13 TeV have been systematically studied using the newly released parton and cascade model paciae 4.0 based on pythia 8.3. The available experimental data are well reproduced across all analyzed aspects. This theoretical method can be easily extended to anywhere the experimental data for <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>p</mi><mi>p</mi></mrow></math> collisions are currently unavailable. Furthermore, since <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>p</mi><mi>p</mi></mrow></math> collisions serve as the baseline for heavy-ion collisions, our results can provide a valuable resource for both experimentalists and theorists.

Zhen Xie

An-Ke Lei

Hua Zheng

Wenchao Zhang

Dai-Mei Zhou

Zhi-Lei She

Yu-Liang Yan

Ben-Hao Sa

Pseudorapidity density distributions of charged particles and transverse-momentum spectra of identified particles in <math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>p</mi><mi>p</mi></mrow></math> collisions in the PACIAE 4.0 model

We revisit birefringence effects associated with the evolution of the polarization of light as it propagates through axion dark matter or the background of a passing gravitational wave (GW). We demonstrate that this can be described by a unified formalism, highlighting a synergy between searches for axions and high-frequency GWs. We show that by exploiting this framework, the optical cavities used by the ALPS II experiment can potentially probe axion masses in the range <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>m</mi><mi>a</mi></msub><mo>∼</mo><mrow><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>9</mn></mrow></msup><mi>–</mi><mrow><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>6</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi>eV</mi></mrow></mrow></math>, offering competitive sensitivity with existing laboratory and astrophysical searches. Also building on this approach, we propose using these optical cavities to search for high-frequency GWs by measuring changes in the polarization of their circulating laser fields. This makes it a promising method for exploring, in the near future, GWs with frequencies above 100 MHz and strain sensitivities on the order of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>14</mn></mrow></msup><mtext> </mtext><mtext> </mtext><msup><mrow><mi>Hz</mi></mrow><mrow><mo>−</mo><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msup></mrow></math>. Such sensitivity allows the exploration of currently unconstrained parameter space, complementing other high-frequency GW experiments. This work contributes to the growing community investigating novel approaches for high-frequency GW detection.

Spain

Camilo García-Cely

Luca Marsili

Andreas Ringwald

Aaron D. Spector

Polarimetric searches for axion dark matter and high-frequency gravitational waves using optical cavities

This study investigates quantum gravity effects within the framework of an effective loop quantum gravity black hole (LQG-BH) model parameterized by $$\zeta $$ , utilizing precision measurements from solar system experiments and astrophysical observations. We analyze three classical tests of general relativity (GR): (1) Light deflection constrained by very long baseline interferometry (VLBI) observations of quasar radio signals, (2) Shapiro time delay measurements from the Cassini mission, and (3) Mercury’s perihelion precession determined by MESSENGER mission data. Additionally, we extend our analysis to Earth-orbiting LAGEOS satellites and the relativistic trajectory of the S2 star orbiting the Galactic Center supermassive BH Sagittarius $$\textrm{A}^*$$ (Sgr $$\textrm{A}^{*}$$ ). Our multi-probe approach reveals that the tightest constraint on the LQG parameter comes from Mercury’s perihelion precession, yielding an upper bound $$\zeta \lesssim 10^{-2}$$ . These results establish new observational benchmarks for probing quantum gravity effects.

Wen-Juan Ai

Ruo-Ting Chen

Li-Gang Zhu

Jian-Pin Wu

Probing loop quantum effects through solar system experiments: observational signatures and parameter constraints