arXiv subjects

Ankit Anand

Publications and source records attributed to Ankit Anand.

At least 37 records · Page 2Linked to original sources

arXiv2025

LearnLM: Improving Gemini for Learning

Today's generative AI systems are tuned to present information by default, rather than engage users in service of learning as a human tutor would. To address the wide range of potential education use cases for these systems, we reframe the challenge of injecting pedagogical behavior as one of \textit{pedagogical instruction following}, where training and evaluation examples include system-level instructions describing the specific pedagogy attributes present or desired in subsequent model turns. This framing avoids committing our models to any particular definition of pedagogy, and instead allows teachers or developers to specify desired model behavior. It also clears a path to improving Gemini models for learning -- by enabling the addition of our pedagogical data to post-training mixtures -- alongside their rapidly expanding set of capabilities. Both represent important changes from our initial tech report. We show how training with pedagogical instruction following produces a LearnLM model (available on Google AI Studio) that experts substantially prefer across a diverse set of learning scenarios, with average preference strengths of +31\% over GPT-4o, +11\% over Claude 3.5 Sonnet, and +13\% over the Gemini 1.5 Pro model on which LearnLM was based.

cs.CY↗

arXiv2025

Melodic and Metrical Elements of Expressiveness in Hindustani Vocal Music

This paper presents an attempt to study the aesthetics of North Indian Khayal music with reference to the flexibility exercised by artists in performing popular compositions. We study expressive timing and pitch variations of the given lyrical content within and across performances and propose computational representations that can discriminate between different performances of the same song in terms of expression. We present the necessary audio processing and annotation procedures, and discuss our observations and insights from the analysis of a dataset of two songs in two ragas each rendered by ten prominent artists.

eess.AS↗

arXiv2025

Van der Waals Black Holes: Universality, Quantum Corrections, and Topological Classifications

In this paper, we investigate the universal extremality relation and thermodynamic topology of Van der Waals (VdW) black holes-solutions of Einstein's equations whose thermodynamic behavior closely resembles that of Van der Waals fluids. In the classical case, the black hole entropy obeys the Bekenstein-Hawking area law and satisfies the standard universality relation. We then incorporate quantum corrections using three distinct frameworks: the Generalized Uncertainty Principle (GUP), the Extended Uncertainty Principle (EUP), and Rainbow Gravity. While these corrections modify the entropy law, we find that a generalized form of the universal extremality relation still holds. Next, we explore the thermodynamic topology of VdW black holes, focusing on the distribution of topological charges. Our analysis reveals that variations in the black hole and model parameters lead to significant changes in topological classifications and stability, as quantified by winding numbers. In the GUP-corrected case, topological charge distributions exhibit robustness against parameter variations, suggesting classification stability. For EUP-corrected black holes, we identify two distinct topological classes, with some configurations displaying three non-zero topological charges and others maintaining a total charge of zero, despite changes in individual charge counts. The Rainbow Gravity-corrected scenario shows similar consistency in topological behavior.

gr-qc↗

arXiv2025

Black Holes in Lorentz-Violating Gravity: Thermodynamics, Geometry, and Particle Dynamics

We investigate the thermodynamics, topology, and geometry of black holes in Lorentz-violating gravity. Modifications in the theory by perturbative parameter lead to coupled changes in horizon structure and thermodynamic behaviour, allowing us to derive generalized universal relations and explore implications for the Weak Gravity Conjecture. The thermodynamic topology reveals distinct topological charges, with photon spheres identified as robust topological defects. Our analysis shows that the Ruppeiner curvature remains universally negative across thermodynamic ensembles, indicating dominant attractive interactions among microstructures. This ensemble-independent behaviour highlights a fundamental thermodynamic universality in Lorentz-violating settings. Together, these results provide a consistent and rich framework for understanding black hole microphysics and gravitational consistency in modified theories. We further study the motion of timelike test particles in these black hole spacetimes by analyzing the effective potential shaped by the Lorentz-violating couplings. The resulting dynamics reveal the existence of bound orbits and stable circular trajectories, with the location of the innermost stable circular orbit and turning points significantly influenced by the parameters $\ell_{1,2}$, and the cosmological constant. Numerical simulations of trajectories in the $x-y,\,x-z$, and 3D planes show precessing, bounded, and plunging orbits, depending on the particle's specific energy and angular momentum. These results highlight how Lorentz-violating effects alter the structure of geodesic motion and provide potential observational signatures in the dynamics of massive particles near black holes.

gr-qc↗

arXiv2025

Thermodynamic Curvature and Topological Insights of Hayward Black Holes with String Fluids

In this paper, we study the influence of string fluids on the extended thermodynamic structure and microscopic interactions of Hayward black holes by employing thermodynamic geometry as an empirical tool. Using the novel equation of state obtained for regular black holes surrounded by string fluids, we analyze the extended phase space with enthalpy as the central thermodynamic potential. By examining the behavior of the normalized Ruppeiner curvature scalar $R_N$ in the temperature-volume $(T,V)$ plane, we analyzed the influence of the string fluid parameters on the microstructure of the black hole. Our analysis reveals that the presence of string fluids significantly modifies the dominant microscopic interactions, transitioning from attractive to repulsive regimes depending on the charge and volume of the black hole. We see that the thermodynamic curvature effectively detects critical points and phase transitions, reflecting the nature of repulsive or attractive interactions among black hole microstructures. We further investigate thermodynamic topology to provide a novel classification scheme for stability and phase behavior, delineating local stable and unstable regions in parameter space. We investigate the thermodynamic topology of Hayward-AdS black holes surrounded by string fluids, showing that the number and type of topological charges depend on the parameters $ε$ and $b$, revealing phase transitions and stability characteristics encoded in the global topological charge $W$. This integrated study of the thermodynamic geometry and topology structure enhances the understanding of Hayward black holes surrounded by string fluids, showing overall thermodynamic stability and configuration with significant implications for holographic duality and potential astrophysical observations.

gr-qc↗

arXiv2025

Evaluating Gemini in an arena for learning

Artificial intelligence (AI) is poised to transform education, but the research community lacks a robust, general benchmark to evaluate AI models for learning. To assess state-of-the-art support for educational use cases, we ran an "arena for learning" where educators and pedagogy experts conduct blind, head-to-head, multi-turn comparisons of leading AI models. In particular, $N = 189$ educators drew from their experience to role-play realistic learning use cases, interacting with two models sequentially, after which $N = 206$ experts judged which model better supported the user's learning goals. The arena evaluated a slate of state-of-the-art models: Gemini 2.5 Pro, Claude 3.7 Sonnet, GPT-4o, and OpenAI o3. Excluding ties, experts preferred Gemini 2.5 Pro in 73.2% of these match-ups -- ranking it first overall in the arena. Gemini 2.5 Pro also demonstrated markedly higher performance across key principles of good pedagogy. Altogether, these results position Gemini 2.5 Pro as a leading model for learning.

cs.CY↗

arXiv2025

$κ$-Entanglement Entropy from Black Hole

In this work, we explore the entanglement entropy equipped with the $κ$-algebra. This entanglement entropy is computed through the geometric setup as performed by Hartman-Maldacena, which, in their prescription, finds that the entropy grows linearly in time. In our case, we show that the $κ$-algebra embedding provides a richer scenario where the third-order corrections in time added from $κ$-algebra to entanglement entropy imply that the growth of quantum correlations between subsystems is more intricate than a simple linear increase into the dynamics of black hole thermalization and quantum information flow. In the context of holography, such corrections suggest that the thermalization process is not instantaneous but involves higher-order interactions between subsystems.

hep-th↗

arXiv2025

Black holes surrounded by massive vector fields in Kaluza-Klein gravity

We present an exact black hole solution surrounded by massive vector fields predicted by Kaluza-Klein (KK) gravity. KK gravity in four dimensions (4D) is of particular interest, as it predicts a tower of particle states, including gravitons with spin-0 and spin-1 components, in addition to the massless spin-2 gravitons of general relativity. The extra degrees of freedom in the gravitational sector modify the law of gravity, allowing the theory to explain the effects attributed to dark matter in the universe. In this paper, we construct a black hole solution surrounded by massive spin-1 gravitons within KK theory. In addition to the influence of the massive vector fields, we incorporate an interaction term between the black hole and the massive vector field. The black hole solution is affected by the mass of the spin-1 graviton and an additional parameter that encodes corrections to Newton's constant, as well as the coupling between the massive vector field and the black hole mass. We find that the coupling between the massive vector field and the black hole mimics the effect of an electric charge. To this end, we investigate the accretion disk, quasinormal modes (QNMs), and the stability of the black hole spacetime. Finally, we use Event Horizon Telescope (EHT) observations of Sgr A* to constrain the black hole parameters.

gr-qc↗

arXiv2025

GRAIL: Graph Edit Distance and Node Alignment Using LLM-Generated Code

Graph Edit Distance (GED) is a widely used metric for measuring similarity between two graphs. Computing the optimal GED is NP-hard, leading to the development of various neural and non-neural heuristics. While neural methods have achieved improved approximation quality compared to non-neural approaches, they face significant challenges: (1) They require large amounts of ground truth data, which is itself NP-hard to compute. (2) They operate as black boxes, offering limited interpretability. (3) They lack cross-domain generalization, necessitating expensive retraining for each new dataset. We address these limitations with GRAIL, introducing a paradigm shift in this domain. Instead of training a neural model to predict GED, GRAIL employs a novel combination of large language models (LLMs) and automated prompt tuning to generate a program that is used to compute GED. This shift from predicting GED to generating programs imparts various advantages, including end-to-end interpretability and an autonomous self-evolutionary learning mechanism without ground-truth supervision. Extensive experiments on seven datasets confirm that GRAIL not only surpasses state-of-the-art GED approximation methods in prediction quality but also achieves robust cross-domain generalization across diverse graph distributions.

cs.LG↗

arXiv2025

Cracking the Code of Action: a Generative Approach to Affordances for Reinforcement Learning

Agents that can autonomously navigate the web through a graphical user interface (GUI) using a unified action space (e.g., mouse and keyboard actions) can require very large amounts of domain-specific expert demonstrations to achieve good performance. Low sample efficiency is often exacerbated in sparse-reward and large-action-space environments, such as a web GUI, where only a few actions are relevant in any given situation. In this work, we consider the low-data regime, with limited or no access to expert behavior. To enable sample-efficient learning, we explore the effect of constraining the action space through $\textit{intent-based affordances}$ -- i.e., considering in any situation only the subset of actions that achieve a desired outcome. We propose $\textbf{Code as Generative Affordances}$ $(\textbf{$\texttt{CoGA}$})$, a method that leverages pre-trained vision-language models (VLMs) to generate code that determines affordable actions through implicit intent-completion functions and using a fully-automated program generation and verification pipeline. These programs are then used in-the-loop of a reinforcement learning agent to return a set of affordances given a pixel observation. By greatly reducing the number of actions that an agent must consider, we demonstrate on a wide range of tasks in the MiniWob++ benchmark that: $\textbf{1)}$ $\texttt{CoGA}$ is orders of magnitude more sample efficient than its RL agent, $\textbf{2)}$ $\texttt{CoGA}$'s programs can generalize within a family of tasks, and $\textbf{3)}$ $\texttt{CoGA}$ performs better or on par compared with behavior cloning when a small number of expert demonstrations is available.

cs.AI↗

arXiv2025

Quantum Corrections and Extremality: A Generalized Universal Relation

Logarithmic corrections to the entropy of extremal black holes have proven effective in precisely matching the microscopic degeneracies obtained from string-theoretic as well as a non-perturbative quantum correction manifests as an exponential term in the black hole entropy. In this work, we extend the universal relation proposed by Goon and Penco by deriving a generalized form where entropy is not just the Bekenstein-Hawking entropy. Our analysis treats entropy as a general function of the horizon radius, and with the help of that, we formulate the generalized universal relation. We show that, in the case of Bekenstein-Hawking entropy, the generalized relation coincides with the original universal relation by Goon and Penco. Furthermore, we explore the implications of logarithmic and exponential corrections to entropy and test the validity of the generalized universal relation under these modifications.

hep-th↗

arXiv2025

Thermodynamic Extremality in Power-law AdS Black Holes A Universal Perspective

This study investigates the universal relation between Goon and Penco (GP) proposed within the frameworks of Power-Maxwell, Power-Yang-Mills, and Maxwell-Power-Yang-Mills black holes. We begin by analyzing these black holes' thermodynamics and then calculating the perturbed metric and thermodynamic quantities by perturbing the action. Our objective is to examine the consistency of the GP relation across various power-law terms in the field equations, aiming to gain deeper insights into the nature of these black holes. The GP connection remains robust across different power spacetimes, indicating that this relation is a universal feature of black holes.

hep-th↗

arXiv2025

Effect of Non-Extensive Parameter on Page Curve

This work employs the quantum extremal surface framework to compute the Page curve for black holes corrected by non-extensive entropy. The entropy of Hawking radiation increases linearly with time, leading to the persistence of the information paradox for non-extensive entropy-corrected black holes. At late time, we extremize the generalized entropy functional; incorporating contributions from both matter and the quantum extremal island, we establish that the entanglement entropy of Hawking radiation saturates to the non-extensive extension of the Bekenstein-Hawking entropy. Finally, we study the dependence of non-extensive parameters on the Page time.

hep-th↗

arXiv2025

AutoMix: Automatically Mixing Language Models

Large language models (LLMs) are now available from cloud API providers in various sizes and configurations. While this diversity offers a broad spectrum of choices, effectively leveraging the options to optimize computational cost and performance remains challenging. In this work, we present Automix, an approach that strategically routes queries to larger LMs, based on the approximate correctness of outputs from a smaller LM. Central to Automix are two key technical contributions. First, it has a few-shot self-verification mechanism, which estimates the reliability of its own outputs without requiring extensive training. Second, given that self-verification can be noisy, it employs a POMDP based router that can effectively select an appropriately sized model, based on answer confidence. Experiments across five language models and five challenging datasets show that Automix consistently surpasses strong baselines, reducing computational cost by over 50% for comparable performance.

cs.CL↗

arXiv2024

Universal Relations with the Non-Extensive Entropy Perspective

Recent advancements in black hole thermodynamics have introduced corrections to elucidate the relationship between entropy and extremality bound of black holes. Traditionally, this relationship has been studied in the context of black holes characterized by Bekenstein-Hawking entropy. However, this study extends the investigation to encompass non-extensive generalizations of entropy. We introduce a minor constant correction, denoted as $(\varepsilon)$, and examine the universal relations for a charged Anti-de Sitter (AdS) black hole. Our findings indicate that these universal relations do not hold for the charged AdS black hole when described by the non-extensive generalizations of entropy. Of course, with some adjustments, the universality relations are met. In contrast, the universal relations remain compatible when the black hole is described by Bekenstein-Hawking entropy.

gr-qc↗

arXiv2024

Stability of Extremal Black Holes and Weak Cosmic Censorship Conjecture in Kiselev Spacetime

In this study, we investigate the Weak Gravity Conjecture (WGC) and Weak Cosmic Censorship Conjecture (WCCC) for a quantum-corrected Reissner-Nordström Anti-de Sitter (RN-AdS) black hole embedded in Kiselev spacetime. By making small perturbations to the action and using WGC, we investigate the stability of black holes and predict the existence of lighter particles in the spectrum. Using the scattering of a charged scalar field, we study the WCCC. We verify under certain conditions on the temperature of the black hole, the second law holds for near-extremal black holes. Finally, we demonstrate that the WCCC holds for both extremal and near-extremal black holes.

gr-qc↗

arXiv2024

Exploring a novel Einstein--Rosen BTZ wormhole

We introduce a novel Einstein-Rosen BTZ wormhole metric as a solution to the Einstein field equations with a negative cosmological constant and explore in detail its various phenomenological aspects. We show that the wormhole metric is characterized by a horizon at the throat, resembling a black hole horizon. This implies that our wormhole metric describes a one-way traversable wormhole at the throat, with Hawking radiation observed by an observer located at some distance from the wormhole. It is also found the same Hawking temperature using the BTZ-like coordinates and Kruskal-like coordinates. This temperature is invariant not only on the type of coordinates but also the nature of the spin of quantum fields. Importantly, we find that at the wormhole throat, the spacetime is not a pure vacuum solution, but rather contains an exotic string matter source with negative tension, which may stabilize the wormhole geometry. To this end, we found that the size of the wormhole throat is proportional to the number of quantum bits suggesting a possible implications on ER=EPR. Further we studied the particle dynamics and, finally, we tested the ANEC with a test scalar and vector fields. For the double null-component computed in BTZ coordinates, we found an apparent divergence at the wormhole throat, which is then shown to be regularized by means of Kruskal-like coordinates. The ANEC for such a scalar/vector field is violated at the wormhole throat.

gr-qc↗

arXiv2024

Analyzing WGC and WCCC through Charged Scalar Fields Fluxes with Charged AdS Black Holes Surrounded by Perfect Fluid Dark Matter in the CFT Thermodynamics

In this paper, we conduct a comprehensive investigation into the weak cosmic censorship conjecture (WCCC) for Reissner-Nordström (R-N) AdS black holes that are influenced by Perfect Fluid Dark Matter (PFDM). Our study is framed within the context of Conformal Field Theory (CFT) thermodynamics. We delve into the principles of energy flux and mass-energy equivalence to explore the interplay between the weak gravity conjecture (WGC) and the WCCC. Our analysis begins by examining the interaction between incoming and outgoing energy fluxes, which induces changes in the black hole's properties. By applying the first law of thermodynamics, we assess the validity of the second law in these dynamic scenarios. We also consider equilibrium conditions that involve both absorption and superradiance processes. Utilizing the framework of black hole thermodynamics within CFT, we demonstrate that the WCCC is upheld if the black hole is in or near an extremal state, particularly when it is subjected to radiation and particle absorption. This finding is significant as it reinforces the robustness of the WCCC under these specific conditions. Furthermore, we uncover additional insights by employing mass-energy equivalence principles and conducting second-order approximations near the extremality state. Specifically, we find that when a black hole radiates and its central charge surpasses the scaled electric charge, the emitted superradiant particles adhere to the WGC. This adherence results in the black hole moving away from its extremal state, thereby maintaining the WCCC.

hep-th↗