Motivated by the work of Longhi and Materassi, who constructed a realization of the (centerless) <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>BMS</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></math> algebra for the massive Klein-Gordon field in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>3</mn><mo>+</mo><mn>1</mn></math> dimensions, we build a realization of the (centerless) massless <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>BMS</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></math> algebra including superrotations. This realization depends only on the momenta in the light cone expressed in celestial coordinates without any reference to the Klein-Gordon field. The quadratic Casimir of the Lorentz algebra is written in terms of a second order differential operator and the volume form plays an essential role in this construction. The <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>BMS</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></math> algebra in terms of vector fields shows its kinematical nature, like the Poincaré algebra. We also construct a dynamical realization of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>BMS</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></math> from the symplectic structure on the solutions of the massless four-dimensional Klein-Gordon field in terms of quadratic expressions of the Fourier modes and plane waves invariant under translations. Using the Mellin transform, we rewrite the Klein-Gordon field in terms of the boost invariant basis, and write down the corresponding <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>BMS</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></math> realization. We also provide the relation with spherical harmonics, linking our results with the solutions of Longhi-Materassi, which are in fact a subset of ours.

Spain

Carles Batlle

Italy

Roberto Casalbuoni

Daniele Dominici

United Kingdom

José Figueroa-O’Farrill

Joaquim Gomis

Celestial kinematical interpretation for an extended <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>BMS</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></math> algebra

Quantum field theory in the presence of localized solitons is more complicated than vacuum sector quantum field theory, largely as a result of the soliton’s zero modes. In the present work, we try to understand to what extent this situation carries over to extended solitons. To this end, we explicitly construct the quantum state corresponding to a domain wall string or membrane, treating the zero modes carefully. This is done both for compact and also infinitely extended solitons. As an application, we calculate the differential probability for a domain wall string’s translation mode, with a given momentum, to be excited by a single quantum of incoming radiation.

China

Jarah Evslin

Armenia

Hui Liu

An extended Soliton’s zero modes

We analyse electromagnetic leptogenesis within the framework of an effective field theory, where the dynamics is governed by the gauge-invariant dipole operator $${\mathcal{O}}_{NB}=\left(\overline{L}{\sigma }^{\mu \nu }N\right)\widetilde{H}{B}_{\mu \nu }$$ . The Wilson coefficient $\textit{C}$ is matched at one loop and evolved to the electroweak scale via renormalisation-group (RG) running. After electroweak symmetry breaking, we compute flavour-dependent decay widths and CP asymmetries for the two-body modes $\textit{N}$ → $\textit{νγ}$ and $\textit{N}$ → $\textit{νZ}$, and solve the fully flavoured Boltzmann equations. In the $\textit{N}$ -dominated regime, the freeze-out baryon asymmetry is $${Y}_{B}^{\text{FO}}\lesssim {1}{0}^{-{17}}$$ , far below the observed value $${Y}_{B}^{\text{obs}}\simeq 8.7\times {10}^{-11}$$ . The suppression is structural: gauge invariance forces a Higgs insertion; therefore the dipole coupling scales as $$\mu \propto v/{M}_{\psi}^{2}$$ , while the matched Wilson coefficient $\textit{C}$ is loop-generated and further suppressed by RG running. We note that in the quasi-degenerate limit the self-energy resonance can be operative and suggest a plausible path to $${Y}_{B}^{\text{obs}}$$ .

Japan

Rin Takada

Electromagnetic leptogenesis — an EFT-consistent analysis via Wilson coefficients. Part I. Low-scale, non-resonant regime

This paper investigates the normal modes of a probe scalar field in a five-dimensional AdS-Schwarzschild black hole with the brick wall boundary condition near the horizon. We employ various techniques to compute the spectrum and analyze its properties. Our results reveal a linear dependence of the spectrum on the principal quantum number while demonstrating a nontrivial dependence on the angular momentum quantum number. We compute the spectral form factor (SFF) and find a dip-ramp-plateau structure, with the slope of the ramp approaching unity as the brick wall nears the horizon. This feature appears to vanish when the horizon size becomes much larger compared to the anti–de Sitter length. We also observe that as the brick wall approaches the horizon, the poles of the retarded Green’s function condense on the real line, leading to an emergent thermal behavior in the boundary theory. This work extends previous studies on lower-dimensional black holes to higher dimensions, providing insights into the connection between black hole microstate models and boundary chaos. Our findings contribute to the ongoing discussions on the information paradox and the nature of black hole interiors in the context of anti–de Sitter/conformal field theory correspondence.

India

Suman Das

Somnath Porey

Baishali Roy

Brick wall in an AdS-Schwarzschild black hole: Normal modes and emerging thermality

In this article, we investigate the orbital dynamics and quasi-periodic oscillations (QPOs) surrounding a static, spherically symmetric geometry of an Einstein–nonlinear Maxwell–-Yukawa (ENLMY) black hole (BH). Using the Hamiltonian formalism, we derive equations of motion and analyze the effective potential. We determine the innermost stable circular orbit (ISCO) and innermost bound circular orbit (IBCO) radii for different values of the Yukawa parameters $$\lambda $$ and $$\delta $$ , and classify periodic orbits via rational frequency analysis, highlighting deviations from Schwarzschild geometry. We also study gravitational wave (GW) emission from periodic orbits and show how Yukawa terms affect GW signals. Fundamental frequencies are computed, and QPOs are analyzed using relativistic precession, warped disk, and tidal disruption models. By increasing $$\lambda $$ , the ENLMY spacetime effectively mimics the behavior of a Schwarzschild spacetime. Constraints on the BH mass and Yukawa parameters are derived using QPO data from stellar-mass (XTE J1550-564, GRO J1655-40, GRS 1915+105), intermediate-mass (M82 X-1), and supermassive (SgrA*) BHs within the relativistic precession model by employing a Markov chain Monte Carlo analysis.

Pakistan

Tehreem Zahra

Oreeda Shabbir

Bushra Majeed

Azerbaijan

Mubasher Jamil

Uzbekistan

Javlon Rayimbaev

Abubakir Shermatov

Gravitational wave radiation from periodic orbits and quasi-periodic oscillations in an Einstein nonlinear Maxwell–Yukawa black hole

The Sakai-Sugimoto holographic model is famous for implementing the approximate chiral symmetry of QCD and reproducing the Chiral Lagrangian in a top-down approach. In this manuscript, we revisit the model in a formalism that is somewhat different from the original work by Sakai and Sugimoto: we start by identifying boundary degrees of freedom and splitting the bulk equations of motion into dynamical ones and constraints. The former are then solved to all orders in derivatives of the boundary fields. The constraints are left unsolved, leaving the dynamical degrees of freedom off-shell. This approach enables us to systematically derive the effective action of the boundary theory. The derived effective action is very rich in physics: it contains an U($\textit{N}$ ) multiplet of massless pseudoscalars interacting (via trilinear and higher terms) with towers of massive (axial-)vector mesons. In contrast to the previous studies, our effective action is non-local. The original Chiral Lagrangian is recovered as its local expansion in small $\textit{π}$-meson momenta (derivative expansion). We particularly zoom in on the values of four derivative terms couplings, the low energy constants, and compare those with the ones reported in the literature.

Israel

Michael Lublinsky

Timofey Solomko

Sakai-Sugimoto model in an off-shell: Chiral Lagrangian to all orders

The global symmetries in maximally supersymmetric theories of gravity in <italic>d</italic>&#8239;&#8805;&#8239;4 are shown to have a universal form in light-cone superspace. The procedure for deriving an all order expression for the <math altimg='si1.svg'><mrow><mi>d</mi><mo linebreak='goodbreak'>=</mo><mn>4</mn></mrow></math> case is also discussed.

Sudarshan Ananth

Nipun Bhave

An ‘exceptional’ form for symmetries in maximal supergravity

We report on a search for axion dark matter in the frequency range near 5.9 GHz, conducted using the haloscope technique. The experiment employed an 8-cell microwave resonator designed to extend the accessible frequency range by a multifold factor relative to conventional single-cell configurations, while maintaining a large detection volume. To enhance sensitivity, a flux-driven Josephson parametric amplifier operating near the quantum noise limit was utilized, together with a sideband-summing method that coherently combines mirrored spectral components generated by the Josephson parametric amplifier. Data were acquired over the frequency range 5.83–5.94 GHz. With no statistically significant excess observed, we exclude axion-photon couplings <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>g</mi></mrow><mrow><mi>a</mi><mi>γ</mi><mi>γ</mi></mrow></msub></mrow></math> down to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>1.2</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>14</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mrow><msup><mrow><mi>GeV</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></mrow></math> at a 90% confidence level. The achieved sensitivity approaches the Kim-Shifman-Vainshtein-Zakharov benchmark prediction, setting the most stringent limits to date in this range.

South Korea

Saebyeok Ahn

Çağlar Kutlu

Soohyung Lee

SungWoo Youn

Sergey V. Uchaikin

Sungjae Bae

Sweden

Junu Jeong

Arjan F. van Loo

Yasunobu Nakamura

Seongjeong Oh

Jihn E. Kim

Yannis K. Semertzidis

Probing Kim-Shifman-Vainshtein-Zakharov Axion Dark Matter near 5.9 GHz Using an 8-Cell Cavity Haloscope

Extremely weak long-range forces may lead to apparent violations of the equivalence principle. The final MICROSCOPE result, leading at 95% CL to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">|</mo><mi>δ</mi><mo stretchy="false">|</mo><mo>&lt;</mo><mn>4.5</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>15</mn></mrow></msup></math> or <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>6.5</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>15</mn></mrow></msup></math> for a positive or negative Eötvös parameter <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>δ</mi></math>, requires taking into account the spin of the mediator, and the sign of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="normal">Δ</mi><mo stretchy="false">(</mo><mi>Q</mi><mo>/</mo><msub><mrow><mi>A</mi></mrow><mrow><mi>r</mi></mrow></msub><msub><mrow><mo stretchy="false">)</mo></mrow><mrow><mtext>Ti</mtext><mi mathsize="small">−</mi><mtext>Pt</mtext></mrow></msub></mrow></math> (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Q</mi></math> denoting the new charge involved). A coupling to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo>−</mo><mi>L</mi></math> or <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi></math> should verify <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">|</mo><msub><mi>g</mi><mrow><mi>B</mi><mo>−</mo><mi>L</mi></mrow></msub><mo stretchy="false">|</mo><mo>&lt;</mo><mn>1.1</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>25</mn></mrow></msup></math> or <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">|</mo><msub><mi>g</mi><mi>B</mi></msub><mo stretchy="false">|</mo><mo>&lt;</mo><mn>8</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>25</mn></mrow></msup></math>, for a spin-1 mediator of mass <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>m</mi><mo>&lt;</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>14</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi>eV</mi><mo stretchy="false">/</mo><msup><mi>c</mi><mn>2</mn></msup></math>, with slightly different limits of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>1.3</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>25</mn></mrow></msup></math> or <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>6.6</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>25</mn></mrow></msup></math> in the spin-0 case. The limits increase with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>m</mi></math>, in a way which depends on the density distribution within the Earth. This involves an hyperbolic form factor, expressed through a bilateral Laplace transform as <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="normal">Φ</mi><mo stretchy="false">(</mo><mi>x</mi><mo>=</mo><mi>m</mi><mi>R</mi><mo stretchy="false">)</mo><mo>=</mo><mo stretchy="false">⟨</mo><mi>sinh</mi><mi>m</mi><mi>r</mi><mo>/</mo><mi>m</mi><mi>r</mi><mo stretchy="false">⟩</mo></mrow></math>, related by analytic continuation to the Earth form factor <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Φ</mi><mo stretchy="false">(</mo><mi>i</mi><mi>x</mi><mo stretchy="false">)</mo><mo>=</mo><mo stretchy="false">⟨</mo><mi>sin</mi><mi>m</mi><mi>r</mi><mo>/</mo><mi>m</mi><mi>r</mi><mo stretchy="false">⟩</mo></math>. It may be expressed as <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Φ</mi><mo stretchy="false">(</mo><mi>x</mi><mo stretchy="false">)</mo><mo>=</mo><mfrac><mn>3</mn><msup><mi>x</mi><mn>2</mn></msup></mfrac><mo stretchy="false">(</mo><mi>cosh</mi><mi>x</mi><mo>−</mo><mfrac><mrow><mi>sinh</mi><mi>x</mi></mrow><mi>x</mi></mfrac><mo stretchy="false">)</mo><mo>×</mo><mover accent="true"><mi>ρ</mi><mo stretchy="false">¯</mo></mover><mo stretchy="false">(</mo><mi>x</mi><mo stretchy="false">)</mo><mo>/</mo><msub><mi>ρ</mi><mn>0</mn></msub></math>, where <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>ρ</mi><mo stretchy="false">¯</mo></mover><mo stretchy="false">(</mo><mi>x</mi><mo stretchy="false">)</mo></math> is an effective density, decreasing from the average <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>ρ</mi><mn>0</mn></msub></math> at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>m</mi><mo>=</mo><mn>0</mn></math> down to the density at the periphery. We give general integral or multishell expressions of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Φ</mi><mo stretchy="false">(</mo><mi>x</mi><mo stretchy="false">)</mo></math>, evaluating it, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>ρ</mi><mo stretchy="false">¯</mo></mover><mo stretchy="false">(</mo><mi>x</mi><mo stretchy="false">)</mo></math>, in a simplified 5-shell model. <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">Φ</mi><mo stretchy="false">(</mo><mi>x</mi><mo stretchy="false">)</mo></math> may be expanded as <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>∑</mo><mfrac><msup><mi>x</mi><mrow><mn>2</mn><mi>n</mi></mrow></msup><mrow><mo stretchy="false">(</mo><mn>2</mn><mi>n</mi><mo stretchy="false">+</mo><mn>1</mn><mo stretchy="false">)</mo><mo stretchy="false">!</mo></mrow></mfrac><mfrac><mrow><mo stretchy="false">⟨</mo><msup><mi>r</mi><mrow><mn>2</mn><mi>n</mi></mrow></msup><mo stretchy="false">⟩</mo></mrow><msup><mi>R</mi><mrow><mn>2</mn><mi>n</mi></mrow></msup></mfrac><mo>≃</mo><mn>1</mn><mo>+</mo><mo>.</mo><mn>0827</mn><msup><mi>x</mi><mn>2</mn></msup><mo>+</mo><mo>.</mo><mn>00271</mn><msup><mi>x</mi><mn>4</mn></msup><mo>+</mo><mn>4.78</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>5</mn></mrow></msup><msup><mi>x</mi><mn>6</mn></msup><mo>+</mo><mn>5.26</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>7</mn></mrow></msup><msup><mi>x</mi><mn>8</mn></msup><mo>+</mo><mo>⋯</mo></math>, absolutely convergent for all <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>x</mi></math> and potentially useful up to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>x</mi><mo>≈</mo><mn>5</mn></math>. The coupling limits increase at large <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>x</mi></math> like <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>m</mi><mi>R</mi><mtext> </mtext><msup><mrow><mi>e</mi></mrow><mrow><mi>m</mi><mi>z</mi><mo>/</mo><mn>2</mn></mrow></msup><mo>/</mo><msqrt><mrow><mn>1</mn><mo>+</mo><mi>m</mi><mi>r</mi></mrow></msqrt></mrow></math> (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>z</mi><mo>=</mo><mi>r</mi><mo>−</mo><mi>R</mi></math> being the satellite altitude), getting multiplied by <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mo>≃</mo><mtext> </mtext><mn>1.9</mn></mrow></math>, 34, or <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>1.2</mn><mo>×</mo><msup><mn>10</mn><mn>9</mn></msup></math>, for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>m</mi><mo>=</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>13</mn></mrow></msup><mo>,</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>12</mn></mrow></msup></math> or <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mn>10</mn><mrow><mo>−</mo><mn>11</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi>eV</mi><mo stretchy="false">/</mo><msup><mi>c</mi><mn>2</mn></msup></math>, respectively.

France

Pierre Fayet

Yukawa potential of a nonhomogeneous sphere with new limits on an ultralight boson

Here we discuss the construction of Sp(4; $\textit{ℝ}$) invariant objects in the twistor space for three dimensional conformal field theories. The Sp(4; $\textit{ℝ}$) invariant projective delta function, alongside the Twistor symplectic dot product invariants form the basis for conformal Wightman functions involving conserved currents and ∆ = 1 scalars. For correlators involving scalars with ∆ ≠ 1, generic spinning primaries and parity odd correlators we show that the infinity twistor of $\textit{ℝ}$ must be incorporated into the analysis. We show that this feature can be traced to the Penrose and Witten transforms of these operators that we derive. We then discuss the super-twistor space construction and derive the supersymmetric Penrose transform for $$ \mathcal{N} $$ = 1 theories using the Fourier transform and the supersymmetric Witten transform. We construct OSp( $$ \mathcal{N} $$ |4; $\textit{ℝ}$) invariants and its application to several super-Wightman functions. Similar to the non supersymmetric case, we find an important role played by the (super) infinity twistor which we exemplify through parity odd super-correlators and a supersymmetric contact term.

Aswini Bala

Dhruva K. S

An Ode to the Penrose and Witten transforms in twistor space for 3D CFT