Institute for Theoretical PhysicsUniversity of Cologne
Evolutionary accessibility of random and structured fitness landscapes
Biological evolution can be conceptualized as a search process in the space of gene sequences guided by the fitness landscape, a mapping that assigns a measure of reproductive value to each genotype. Here we discuss probabilistic models of fitness landscapes with a focus on their evolutionary accessibility, where a path in a fitness landscape is said to be accessible if the fitness values encountered along the path increase monotonically. For uncorrelated (random) landscapes with independent and identically distributed fitness values, the probability of existence of accessible paths between genotypes at a distance linear in the sequence length LL becomes nonzero at a nontrivial threshold value of the fitness difference between the initial and final genotype, which can be explicitly computed for large classes of genotype graphs. The behaviour in uncorrelated random landscapes is contrasted with landscape models that display additional, biologically motivated structural features. In particular, landscapes defined by a tradeoff between adaptation to environmental extremes have been found to display a combinatorially large number of accessible paths to all local fitness maxima. We show that this property is characteristic of a broad class of models that satisfy a certain global constraint, and provide further examples from this class.
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Exploring Genre and Success Classification through Song Lyrics using DistilBERT: A Fun NLP Venture

Researchers from the University of Cologne developed a system leveraging DistilBERT to classify song genres and predict both a song's success (based on views) and its approximate release year solely from lyrical content. The system achieved 65% accuracy for genre classification, 79% accuracy for success prediction, and an RMSE of 14.18 for release year estimation using extracted BERT embeddings with SVR.

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Probing the Critical Point (CritPt) of AI Reasoning: a Frontier Physics Research Benchmark

Researchers from Argonne National Laboratory and the University of Illinois Urbana-Champaign, with over 50 collaborators, introduce CritPt, a benchmark to evaluate Large Language Models (LLMs) on unpublished, research-level physics problems. The study found that current LLMs achieve very low accuracy on end-to-end scientific challenges (best base model at 5.7%) but show limited potential on modular sub-tasks, revealing a significant gap in their ability for genuine scientific reasoning and consistent reliability.

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TimeCMA: Towards LLM-Empowered Multivariate Time Series Forecasting via Cross-Modality Alignment

TimeCMA introduces a framework for multivariate time series forecasting that leverages large language models (LLMs) through a novel cross-modality alignment module to generate disentangled yet robust time series embeddings. This approach, combined with efficient last token embedding storage, consistently outperforms state-of-the-art baselines across eight datasets while significantly reducing computational overhead.

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Reasoning RAG via System 1 or System 2: A Survey on Reasoning Agentic Retrieval-Augmented Generation for Industry Challenges

This survey paper from a diverse group of researchers including SenseTime Research provides a comprehensive overview of Reasoning Agentic Retrieval-Augmented Generation (RAG) systems. It introduces a taxonomy categorizing these systems into 'Predefined Reasoning' (System 1) and 'Agentic Reasoning' (System 2), addressing the limitations of basic RAG for complex industry challenges by detailing advancements in dynamic information acquisition and synthesis.

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Empowering Time Series Analysis with Foundation Models: A Comprehensive Survey
Time series data are ubiquitous across diverse real-world applications, making time series analysis critically important. Traditional approaches are largely task-specific, offering limited functionality and poor transferability. In recent years, foundation models have revolutionized NLP and CV with their remarkable cross-task transferability, zero-/few-shot learning capabilities, and multimodal integration capacity. This success has motivated increasing efforts to explore foundation models for addressing time series modeling challenges. Although some tutorials and surveys were published in the early stages of this field, the rapid pace of recent developments necessitates a more comprehensive and in-depth synthesis to cover the latest advances. Our survey aims to fill this gap by introducing a modality-aware, challenge-oriented perspective, which reveals how foundation models pre-trained on different modalities face distinct hurdles when adapted to time series tasks. Building on this perspective, we propose a taxonomy of existing works organized by pre-training modality (time series, language, and vision), analyze modality-specific challenges and categorize corresponding solutions, discussing their advantages and limitations. Beyond this, we review real-world applications to illustrate domain-specific advancements, provide open-source codes, and conclude with potential future research directions in this rapidly evolving field.
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Spatial-Temporal Large Language Model for Traffic Prediction

A Spatial-Temporal Large Language Model (ST-LLM) is developed to enhance traffic prediction by explicitly modeling both spatial and temporal dependencies within a large language model framework. It consistently achieved the best prediction performance on real-world traffic datasets, outperforming existing state-of-the-art models and demonstrating strong generalization capabilities in data-constrained scenarios.

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KurTail : Kurtosis-based LLM Quantization
One of the challenges of quantizing a large language model (LLM) is the presence of outliers. Outliers often make uniform quantization schemes less effective, particularly in extreme cases such as 4-bit quantization. We introduce KurTail, a new post-training quantization (PTQ) scheme that leverages Kurtosis-based rotation to mitigate outliers in the activations of LLMs. Our method optimizes Kurtosis as a measure of tailedness. This approach enables the quantization of weights, activations, and the KV cache in 4 bits. We utilize layer-wise optimization, ensuring memory efficiency. KurTail outperforms existing quantization methods, offering a 13.3\% boost in MMLU accuracy and a 15.5\% drop in Wiki perplexity compared to QuaRot. It also outperforms SpinQuant with a 2.6\% MMLU gain and reduces perplexity by 2.9\%, all while reducing the training cost. For comparison, learning the rotation using SpinQuant for Llama3-70B requires at least four NVIDIA H100 80GB GPUs, whereas our method requires only a single GPU, making it a more accessible solution for consumer GPU.
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Horizon-scale variability of M87* from 2017--2021 EHT observations

The Event Horizon Telescope Collaboration conducted the first multi-epoch polarimetric imaging of M87* at event-horizon scales, observing a stable black hole shadow diameter while detecting substantial year-to-year variability in the ring's azimuthal brightness and linear polarization patterns, along with initial constraints on extended jet emission.

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Identifying the Best Machine Learning Algorithms for Brain Tumor Segmentation, Progression Assessment, and Overall Survival Prediction in the BRATS Challenge
23 Apr 2019
Gliomas are the most common primary brain malignancies, with different degrees of aggressiveness, variable prognosis and various heterogeneous histologic sub-regions, i.e., peritumoral edematous/invaded tissue, necrotic core, active and non-enhancing core. This intrinsic heterogeneity is also portrayed in their radio-phenotype, as their sub-regions are depicted by varying intensity profiles disseminated across multi-parametric magnetic resonance imaging (mpMRI) scans, reflecting varying biological properties. Their heterogeneous shape, extent, and location are some of the factors that make these tumors difficult to resect, and in some cases inoperable. The amount of resected tumor is a factor also considered in longitudinal scans, when evaluating the apparent tumor for potential diagnosis of progression. Furthermore, there is mounting evidence that accurate segmentation of the various tumor sub-regions can offer the basis for quantitative image analysis towards prediction of patient overall survival. This study assesses the state-of-the-art machine learning (ML) methods used for brain tumor image analysis in mpMRI scans, during the last seven instances of the International Brain Tumor Segmentation (BraTS) challenge, i.e., 2012-2018. Specifically, we focus on i) evaluating segmentations of the various glioma sub-regions in pre-operative mpMRI scans, ii) assessing potential tumor progression by virtue of longitudinal growth of tumor sub-regions, beyond use of the RECIST/RANO criteria, and iii) predicting the overall survival from pre-operative mpMRI scans of patients that underwent gross total resection. Finally, we investigate the challenge of identifying the best ML algorithms for each of these tasks, considering that apart from being diverse on each instance of the challenge, the multi-institutional mpMRI BraTS dataset has also been a continuously evolving/growing dataset.
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Efficient Multivariate Time Series Forecasting via Calibrated Language Models with Privileged Knowledge Distillation

TimeKD introduces an efficient framework for multivariate time series forecasting that leverages the robust representation capabilities of Large Language Models while mitigating their high inference costs. This is achieved through a novel privileged knowledge distillation method, which enables a lightweight student model to effectively learn from a calibrated LLM teacher that processes privileged information (future ground truth data) during training, leading to improved forecasting accuracy and superior computational efficiency.

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Quantum speed-up for solving the one-dimensional Hubbard model using quantum annealing
The Hubbard model has occupied the minds of condensed matter physicists for most part of the last century. This model provides insight into a range of phenomena in correlated electron systems. We wish to examine the paradigm of quantum algorithms for solving such many-body problems. The focus of our current work is on the one-dimensional model which is integrable, meaning that there exist analytical results for determining its ground state. In particular, we demonstrate how to perform a gate-based quantum computer simulation of quantum annealing for the Hubbard Hamiltonian. We perform simulations for systems with up to 40 qubits to study the scaling of required annealing time for obtaining the ground state. We find that for the half-filled cases considered, there is a substantial quantum speed-up over algorithms based on the Bethe-ansatz equations.
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Unlocking the Power of SAM 2 for Few-Shot Segmentation

The FSSAM framework effectively adapts the SAM 2 foundation model for few-shot semantic segmentation by converting the task into a "same-object matching" problem, aligning with SAM 2's core competence. This approach, incorporating a Pseudo Prompt Generator, Iterative Memory Refinement, and Support-Calibrated Memory Attention, achieves new state-of-the-art performance on PASCAL-5i and COCO-20i datasets, demonstrating up to a 4.7% mIoU improvement over prior foundation-based methods.

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Mpemba Effects in Quantum Complexity
The Mpemba effect is the phenomenon whereby systems farther from equilibrium may relax faster. In this work, we show that this counterintuitive behavior appears in the very measures that define quantum complexity. Using the framework of quantum resource theories, we study the dynamics of coherence, imaginarity, non-Gaussianity, and magic state resources in random circuit models. Our results reveal that coherence and imaginarity display a quantum Mpemba effect when the system is initialized in resourceful product states, while non-Gaussianity and magic do not. Strikingly, all four resources exhibit the so-called Pontus-Mpemba effect: an initial "preheating" stage accelerates relaxation compared to direct "cooling" dynamics. Taken together, our findings show that Mpemba physics extends beyond thermodynamics and asymmetry, emerging broadly in the resource theories that capture aspects of quantum complexity.
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AI Meets the Classroom: When Do Large Language Models Harm Learning?

Researchers from the University of Cologne and Rotterdam School of Management found that the impact of Large Language Models on student learning depends on how students use them and their existing knowledge. While LLM access generally showed no average effect, substitutive use (e.g., copy-pasting solutions) negatively affected long-term learning and understanding, especially for students with lower prior knowledge, who experienced reduced comprehension.

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SVFT: Parameter-Efficient Fine-Tuning with Singular Vectors

Singular Vector Fine-Tuning (SVFT) proposes a parameter-efficient fine-tuning approach that leverages the singular value decomposition of pre-trained weight matrices for targeted updates. This method achieves performance competitive with full fine-tuning, recovering up to 96% of its accuracy while updating as little as 0.006% to 0.25% of the model parameters across vision and language tasks.

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Is it Gaussian? Testing bosonic quantum states
Gaussian states are widely regarded as one of the most relevant classes of continuous-variable (CV) quantum states, as they naturally arise in physical systems and play a key role in quantum technologies. This motivates a fundamental question: given copies of an unknown CV state, how can we efficiently test whether it is Gaussian? We address this problem from the perspective of representation theory and quantum learning theory, characterizing the sample complexity of Gaussianity testing as a function of the number of modes. For pure states, we prove that just a constant number of copies is sufficient to decide whether the state is exactly Gaussian. We then extend this to the tolerant setting, showing that a polynomial number of copies suffices to distinguish states that are close to Gaussian from those that are far. In contrast, we establish that testing Gaussianity of general mixed states necessarily requires exponentially many copies, thereby identifying a fundamental limitation in testing CV systems. Our approach relies on rotation-invariant symmetries of Gaussian states together with the recently introduced toolbox of CV trace-distance bounds.
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Towards Cross-Modality Modeling for Time Series Analytics: A Survey in the LLM Era

This survey provides a comprehensive analysis of cross-modality modeling for time series analytics in the LLM era, addressing the challenge of integrating textual and numerical time series data. It categorizes approaches by textual data types and integration strategies, finding that incorporating textual data can improve forecasting performance, with numerical and statistical prompts, alongside alignment strategies, showing particular promise.

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XTraffic: A Dataset Where Traffic Meets Incidents with Explainability and More

Researchers from KAUST, Tsinghua University, and other institutions developed XTraffic, the first comprehensive dataset that spatiotemporally aligns traffic time-series data with incident records and detailed road infrastructure attributes. This dataset, collected from California's transportation system throughout 2023, enables the development of more explainable and causally-aware traffic models by integrating previously separated information.

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One Sample is Enough to Make Conformal Prediction Robust
Given any model, conformal prediction (CP) returns prediction sets guaranteed to include the true label with high adjustable probability. Robust CP (RCP) extends this to inputs with worst-case noise. A well-established approach is to use randomized smoothing for RCP since it is applicable to any black-box model and provides smaller sets compared to deterministic methods. However, current smoothing-based RCP requires many model forward passes per each input which is computationally expensive. We show that conformal prediction attains some robustness even with a forward pass on a single randomly perturbed input. Using any binary certificate we propose a single sample robust CP (RCP1). Our approach returns robust sets with smaller average set size compared to SOTA methods which use many (e.g. around 100) passes per input. Our key insight is to certify the conformal prediction procedure itself rather than individual scores. Our approach is agnostic to the setup (classification and regression). We further extend our approach to smoothing-based robust conformal risk control.
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