skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.


Search for: All records

Creators/Authors contains: "Lahn, Nathaniel"

Note: When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external site maintained by the publisher. Some full text articles may not yet be available without a charge during the embargo (administrative interval).
What is a DOI Number?

Some links on this page may take you to non-federal websites. Their policies may differ from this site.

  1. Self-supervised learning (SSL) is at the core of training modern large machine learning models, providing a scheme for learning powerful representations that can be used in a variety of downstream tasks. However, SSL strategies must be adapted to the type of training data and downstream tasks required. We propose resimulation-based self-supervised representation learning (RS3L), a novel simulation-based SSL strategy that employs a method of to drive data augmentation for contrastive learning in the physical sciences, particularly, in fields that rely on stochastic simulators. By intervening in the middle of the simulation process and rerunning simulation components downstream of the intervention, we generate multiple realizations of an event, thus producing a set of augmentations covering all physics-driven variations available in the simulator. Using experiments from high-energy physics, we explore how this strategy may enable the development of a foundation model; we show how RS3L pretraining enables powerful performance in downstream tasks such as discrimination of a variety of objects and uncertainty mitigation. In addition to our results, we make the RS3L dataset publicly available for further studies on how to improve SSL strategies. Published by the American Physical Society2025 
    more » « less
    Free, publicly-accessible full text available February 21, 2026
  2. Abstract We report a gravitational-wave parameter estimation algorithm,AMPLFI, based on likelihood-free inference using normalizing flows. The focus ofAMPLFIis to perform real-time parameter estimation for candidates detected by machine-learning based compact binary coalescence search,Aframe. We present details of our algorithm and optimizations done related to data-loading and pre-processing on accelerated hardware. We train our model using binary black-hole (BBH) simulations on real LIGO-Virgo detector noise. Our model has 6 million trainable parameters with training times 24 h. Based on online deployment on a mock data stream of LIGO-Virgo data,Aframe+AMPLFIis able to pick up BBH candidates and infer parameters for real-time alerts from data acquisition with a net latency of 6 s. 
    more » « less
  3. null (Ed.)
    Discoveries of new phenomena often involve a dedicated search for a hypothetical physics signature. Recently, novel deep learning techniques have emerged for anomaly detection in the absence of a signal prior. However, by ignoring signal priors, the sensitivity of these approaches is significantly reduced. We present a new strategy dubbed Quasi Anomalous Knowledge (QUAK), whereby we introduce alternative signal priors that capture some of the salient features of new physics signatures, allowing for the recovery of sensitivity even when the alternative signal is incorrect. This approach can be applied to a broad range of physics models and neural network architectures. In this paper, we apply QUAK to anomaly detection of new physics events at the CERN Large Hadron Collider utilizing variational autoencoders with normalizing flow. 
    more » « less
  4. Langran, E.; Archambault, L. (Ed.)
    Improving the quantity and quality of STEM teachers is one of the goals of the Noyce Scholarship Grant Program implemented through the National Science Foundation. Here, we examine how the change to remote learning impacted ASU'’s Noyce Scholarship program. Our research question was as follows: what kinds of successes and struggles did STEM Noyce (a) in-service and (b) pre-service scholars experience in the first year of remote teaching during the pandemic? We interviewed three different cohorts of Noyce scholars: preservice teachers, first year teachers and second year teachers. Results showed that some scholars saw benefits to remote learning including more free time for other learning activities. They also observed teachers dedicated to student success. Challenges included an inability to reach all students, a continued focus on standardized tests, and a lack of flexibility within the districts. 
    more » « less
  5. Abstract Despite the f0(980) hadron having been discovered half a century ago, the question about its quark content has not been settled: it might be an ordinary quark-antiquark ($${{\rm{q}}}\overline{{{\rm{q}}}}$$ q q ¯ ) meson, a tetraquark ($${{\rm{q}}}\overline{{{\rm{q}}}}{{\rm{q}}}\overline{{{\rm{q}}}}$$ q q ¯ q q ¯ ) exotic state, a kaon-antikaon ($${{\rm{K}}}\overline{{{\rm{K}}}}$$ K K ¯ ) molecule, or a quark-antiquark-gluon ($${{\rm{q}}}\overline{{{\rm{q}}}}{{\rm{g}}}$$ q q ¯ g ) hybrid. This paper reports strong evidence that the f0(980) state is an ordinary$${{\rm{q}}}\overline{{{\rm{q}}}}$$ q q ¯ meson, inferred from the scaling of elliptic anisotropies (v2) with the number of constituent quarks (nq), as empirically established using conventional hadrons in relativistic heavy ion collisions. The f0(980) state is reconstructed via its dominant decay channel f0(980) →π+π, in proton-lead collisions recorded by the CMS experiment at the LHC, and itsv2is measured as a function of transverse momentum (pT). It is found that thenq= 2 ($${{\rm{q}}}\overline{{{\rm{q}}}}$$ q q ¯ state) hypothesis is favored overnq= 4 ($${{\rm{q}}}\overline{{{\rm{q}}}}{{\rm{q}}}\overline{{{\rm{q}}}}$$ q q ¯ q q ¯ or$${{\rm{K}}}\overline{{{\rm{K}}}}$$ K K ¯ states) by 7.7, 6.3, or 3.1 standard deviations in thepT< 10, 8, or 6 GeV/cranges, respectively, and overnq= 3 ($${{\rm{q}}}\overline{{{\rm{q}}}}{{\rm{g}}}$$ q q ¯ g hybrid state) by 3.5 standard deviations in thepT< 8 GeV/crange. This result represents the first determination of the quark content of the f0(980) state, made possible by using a novel approach, and paves the way for similar studies of other exotic hadron candidates. 
    more » « less
    Free, publicly-accessible full text available December 1, 2026
  6. Free, publicly-accessible full text available September 1, 2026
  7. Free, publicly-accessible full text available September 1, 2026
  8. Free, publicly-accessible full text available September 1, 2026