Machine-Learning Accelerated Calculations of Reduced Density Matrices: arXiv:2511.07367
Strongly correlated quantum systems are famously hard to compute, even for experts with powerful computers, because tracking how many particles interact quickly becomes intractable in a high-dimensional Hilbert space. In this work, we build two AI architectures that learn from small systems and predict the physics of much larger systmes: one self-attention–based neural network (inspired by Transformers) takes rough, unphysical guesses of n-particle reduced density matrices (n-RDMs) and “repairs” them into valid physical ones, while another (a SIREN network) learns the smooth structure of these correlations across momentum space and then interpolates them to larger lattices than it ever saw in training.
Across several benchmark physical models, these AIs not only reproduce detailed many-body correlation patterns but also dramatically accelerate traditional methods like Hartree–Fock. Together, they suggest a future in which AI becomes an assistant for theorists. More precisely, our results illustrate the potential of using NN-based methods for interpolable physical quantities, which might open a new avenue for future research on strongly correlated phases.
THE ASTROPHYSICAL JOURNAL: https://iopscience.iop.org/article/10.3847/1538-4357/adfb7d
Our research (https://www.arxiv.org/abs/2508.09370) delivers a practical advance for astrophysics: a ML approach that reliably classifies the coolest stars and brown dwarfs—objects that dominate our Galaxy and often host planets—without slow, expert-by-eye inspection. Using low-resolution near-infrared spectra, our models achieve ~95% accuracy within one spectral subtype and can also flag key physical traits (surface gravity and metallicity), a capability that scales to the millions of spectra expected from surveys like Gaia, SDSS, and SPHEREx. By automating and standardizing this step, the work accelerates cataloging nearby low-mass objects, improves the search for unusual targets, and strengthens population studies that inform planet formation and Galactic structure.
American Astronomical Society: https://ui.adsabs.harvard.edu/abs/2024AAS...24333006Z/abstract
We analyzed 219 million low-resolution Gaia DR3 spectra and, after rigorous quality cuts, distilled a high-purity set of 37,945 stellar spectra to build calibrated templates. Anchored to SDSS spectral standards, the library spans 3,360–10,200 Å and includes 201 main-sequence templates across OBAFGKM (subtypes 0–9), plus white dwarfs (DA0.5–DA7.0) and carbon stars (dCG, dCK, dCM). The result is a clean, standardized reference for fast, consistent spectral typing and downstream stellar population studies. Github Repo
American Astronomical Society: https://ui.adsabs.harvard.edu/abs/2025AAS...24546403Z/abstract
We build ML tools that read low-resolution infrared spectra to identify the coolest stars and brown dwarfs (M, L, T) with about 95% accuracy—no hand-typing required. Beyond labels, the models also flag metallicity and surface gravity clues, helping us quickly map and understand our smallest, coolest galactic neighbors.
The study of minor bodies in the Solar System is a fundamental area of research in astrophysics. In our lab, we aimed to apply astrometry to determine the proper motions of asteroids using CCD images obtained from the Direct Imaging Camera on the Nickel telescope at Lick Observatory. We first analyzed the properties of the imaging system and reduced our CCD images using dark and flat field frames to obtain high-quality measurements. We then compared our science images with those in the USNO-B star catalog and performed a fit to determine the plate constants of the imaging system, which enabled us to calculate the standard coordinates of the stars and asteroids. We finally determined the proper motions of asteroid Aline. Through this lab, we have demonstrated the successful application of astrometry in determining the proper motions of asteroids using CCD images.
Astronomical spectroscopy involves the usage of telescopes and spectrographs to investigate the light emitted by objects, which provides us insight into their constituent elements and molecules. In this lab, we used an Ocean Optics spectrometer to analyze the spectrum of particular elements, determining their spectral lines and comparing them with the spectra database from the CRC Handbook of Chemistry & Physics. We also investigated the HgCd and He lamp frames, star J0047+03, and star BD+284211 collected by the KAST spectrograph, processed bias subtraction, and flat field division. By comparing the resulting spectrums to those stored in the KAST database and using the linear fitting method, our results demonstrate a linear relationship between the pixel value and wavelength of the elements present.
This lab work aims to explore and characterize the Charged-Coupled Device (CCD), an essential tool in modern astronomy that uses the photoelectric effect to record visible light. Our goal is to operate a CCD detector on the Nickel 1-meter telescope at Lick Observatory, understand its limitations, and analyze the resulting data using Python. This includes investigating physical limitations on light detection, precision of brightness measurement, detector noise, and systematic errors. The hands-on experience will provide us with a comprehensive understanding of photon counting, CCD detector characteristics, and data analysis within a single, condensed exploration.