This study investigates the shadows, scalar perturbations, and quasinormal modes (QNMs) of Grumiller black holes (BHs) within the framework of the Generalized Uncertainty Principle (GUP). The GUP introduces quantum corrections that are most significant near the event horizon, while the Rindler acceleration parameter predominantly influences the spacetime at larger distances. We derive analytical expressions for the photon sphere and shadow radii, showing that quantum corrections cause both to decrease. Additionally, we explore the dynamics of massless scalar perturbations and compute the quasinormal frequencies using the higher-order WKB approximation, supported by time-domain analysis. Our results indicate that while the Rindler acceleration significantly impacts the oscillation frequency and damping rate of gravitational wave (GW) ring downs, the effect of the GUP parameters is relatively small. This work clarifies how these distinct influences operate in different regions of the black hole spacetime and provides valuable insights into the quantum-corrected features of black holes, including their shadows and QNMs.

Jordan

Ahmad Al-Badawi

Azerbaijan

India

Dhruba Jyoti Gogoi

Yassine Sekhmani

Kazakhstan

Kuantay Boshkayev

Shadow and quasinormal modes of GUP corrected Grumiller black holes

<p>We consider Carrollian conformal field theories in two dimensions and construct the boundary Carrollian conformal algebra (BCCA), opening up innumerable possibilities for further studies, given the growing relevance of Carrollian symmetries. We prove that the BCCA emerges by contracting a single copy of the Virasoro algebra. As an application, we construct, for the first time, open null strings and show that, for Dirichlet boundary conditions, we recover the BCCA as the algebra of constraints. We finally reconstruct our string results by taking the null limit of tensile open strings.</p>

Arjun Bagchi

Pronoy Chakraborty

Shankhadeep Chakrabortty

Austria

Stefan Fredenhagen

Daniel Grumiller

Priyadarshini Pandit

Boundary Carrollian Conformal Field Theories and Open Null Strings

<p>We argue there is an interesting triple-scaling limit of quantum gravity, namely when Planck’s constant scales to infinity while Newton’s constant and the speed of light tend to zero, keeping fixed the gravitational coupling <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>G</mi><mi>N</mi></msub><msup><mi>c</mi><mrow><mo>−</mo><mn>4</mn></mrow></msup></math> and the combination <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ℏ</mi><mi>c</mi></math>. We refer to this limiting theory as “tantum gravity” and describe in this Letter some of its main properties and prospects for physics. Most notably, the laws of black hole thermodynamics survive this limit, which means that puzzles related to black holes and their evaporation could be addressed more easily in tantum gravity than in fully fledged quantum gravity.</p>

Florian Ecker

Adrien Fiorucci

Tantum gravity

We construct and discuss generic   <math> <mi>N</mi> </math>  $$ \mathcal{N} $$  = 1 and   <math> <mi>N</mi> </math>  $$ \mathcal{N} $$  = 2 Carroll dilaton supergravity in two dimensions. We apply our general results to the supersymmetric Carroll-Jackiw-Teitelboim model, including a discussion of specific boundary conditions. For   <math> <mi>N</mi> </math>  $$ \mathcal{N} $$  = 2 Carroll dilaton supergravity, we find two versions, dubbed “democratic” and “despotic”.

Luciano Montecchio

Iran

Mohaddese Nejati

Carroll dilaton supergravity in two dimensions

Using effective field theory methods, we derive the Carrollian analog of the geodesic action. We find that it contains both “electric” and “magnetic” contributions that are in general coupled to each other. The equations of motion descending from this action are the Carrollian pendant of geodesics, allowing surprisingly rich dynamics. As an example, we derive Carrollian geodesics on a Carroll–Schwarzschild background and discover an effective potential similar to the one appearing in geodesics on Schwarzschild backgrounds. However, the Newton term in the potential turns out to depend on the Carroll particle’s energy. As a consequence, there is only one circular orbit localized at the Carroll extremal surface, and this orbit is unstable. For large impact parameters, the deflection angle is half the value of the general relativistic light-bending result. For impact parameters slightly bigger than the Schwarzschild radius, orbits wind around the Carroll extremal surface. For small impact parameters, geodesics get reflected by the Carroll black hole, which acts as a perfect mirror.

Canada

Luca Ciambelli

Carroll geodesics

Carroll black holes with an associated Carroll temperature were introduced recently. So far, it is unclear if they exhibit a Hawking-like effect. To solve this, we study scalar fields on Carroll black hole backgrounds. Inspired by anomaly methods, we derive a Hawking-like energy-momentum tensor compatible with the Carroll temperature and the Stefan-Boltzmann law. Key steps in our derivation are the finiteness of energy at the Carroll extremal surface and compatibility with the Carroll-Ward identities, thereby eliminating, respectively, the Carroll analogs of the Boulware and Unruh vacua.

Ankit Aggarwal

Brazil

Dmitri Vassilevich

Carroll-Hawking effect

We construct Carroll-invariant theories with fields propagating outside the Carroll light cone, i.e., at a speed strictly greater than zero (“Carroll swiftons”). We first consider models in flat Carroll spacetime in general dimensions, where we present scalar and vector Carroll swifton field theories. We then turn to the coupling to gravity and achieve in particular in two dimensions a Carroll-invariant scalar swifton by coupling it suitably to Carroll dilaton gravity. Its backreaction on the geometry generates dynamical torsion.

Belgium

France

Marc Henneaux

Patricio Salgado-Rebolledo

Carroll-invariant propagating fields

Leaky boundary conditions in asymptotically AdS spacetimes are relevant to discuss black hole evaporation and the evolution of the Page curve via the island formula. We explore the consequences of leaky boundary conditions on the one-loop partition function of gravity. We focus on JT gravity minimally coupled to a scalar field whose normalizable and non-normalizable modes are both turned on, allowing for leakiness through the AdS boundary. Classically, this yields a flux-balance law relating the scalar news to the time derivative of the mass. Semi-classically, we argue that the usual diffeomorphism-invariant measure is ill-defined, suggesting that the area-non-preserving diffeomorphisms are broken at one loop. We calculate the associated anomaly and its implication on the gravitational Gauss law. Finally, we generalize our arguments to higher dimensions and dS.

Japan

United Kingdom

Romain Ruzziconi

Céline Zwikel

One-loop partition function of gravity with leaky boundary conditions

We argue that the celestial conformal field theory exhibits patterns of a logarithmic conformal field theory. We uncover a Jordan block structure involving the celestial stress tensor and its logarithmic partner, a composite operator built from the stress tensor and the Liouville field. Using a limiting process whose parameter corresponds to the infrared cutoff of gravity, we perform some basic consistency checks, particularly the calculation of two-point correlators, which reveals the expected logarithmic behavior. We comment on the vanishing value of the central charge in the celestial conformal field theory and explain how the logarithmic partner is relevant for its well-behavedness.

Logarithmic celestial conformal field theory

We discuss <math><mi>c</mi></math> functions and their holographic counterpart for two-dimensional field theories with Carrollian conformal fixed points in the UV and the IR. Specifically, we construct asymptotically flat domain wall solutions of three-dimensional Einstein-dilaton gravity that model holographic renormalization group (RG) flows between <math><mrow><msub><mrow><mi>BMS</mi></mrow><mrow><mn>3</mn></mrow></msub></mrow></math> invariant UV and IR fixed points. We prove three theorems for such flows: (1) for every holographic RG flow in <math><mrow><msub><mrow><mi>AdS</mi></mrow><mrow><mn>3</mn></mrow></msub></mrow></math>, there is a corresponding one in flat space, (2) the BMS central charge in the UV cannot be smaller than in the IR, and (3) the UV/IR ratio of Virasoro central charges is identical to the UV/IR ratio of corresponding BMS central charges. Finally, we tentatively propose a Casini–Huerta-like <math><mi>c</mi></math> functions for <math><mrow><msub><mrow><mi>BMS</mi></mrow><mrow><mn>3</mn></mrow></msub></mrow></math>-invariant quantum field theories, inspired by the <math><mrow><msub><mrow><mi>AdS</mi></mrow><mrow><mn>3</mn></mrow></msub><mo>/</mo><msub><mrow><mi>CFT</mi></mrow><mn>2</mn></msub></mrow></math> relation between monotonicity of the <math><mi>c</mi></math> function and the quantum null energy condition.

Max Riegler

Carrollian <math><mi>c</mi></math> functions and flat space holographic RG flows in <math><mrow><msub><mrow><mi>BMS</mi></mrow><mrow><mn>3</mn></mrow></msub></mrow><mo>/</mo><msub><mrow><mi>CCFT</mi></mrow><mn>2</mn></msub></math>