科学研究
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2023.08.08
Can Artificial Intelligence Generate Meaningful Scientific Hypotheses?
The field of Artificial Intelligence (AI) has taken great strides in recent years, particularly with advancements in Large Language Models (LLMs) like ChatGPT. This progress has stirred much public curiosity. However, general-purpose language models like ChatGPT sometimes 'hallucinate' or invent non-existent information when handling specialized subjects. This tendency has led to a common belie...
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2023.08.08
Towards Optimal Inference of Cosmological Large Scale Structures with Neural Quantile Estimation
Traditional analysis of cosmological Large Scale Structures assumes that the likelihood is Gaussian, which unfortunately is not optimal and may even be biased in the non linear regime. Simulation Based Inference (SBI), also known as Likelihood Free Inference or Implicit Likelihood Inference, directly models the Bayesian optimal posterior, but typically needs a large number of simulations to con...
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2023.08.08
Invasion of Alien Planet
This talk is on dynamics of the solar system, we show strong evidence that an alien planet once invaded our solar system. There is a long unsolved mystery concerning a group of asteroids called Jupiter Trojans. Mathematically, there are two symmetric relative equilibrium points for the Sun-Jupiter system, L4 and L5. However, there is a large difference in numbers of observed asteroids: L4 has 6...
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2023.08.08
Modeling dwarf galaxy formation with UniverseMachine
Dwarf galaxies provide unique and rich constraints on galaxy formation and the nature of dark matter. However, the galaxy-halo mass connection at these low-masses still have a lot of uncertainty. With an influx of newly discovered dwarfs near and far, it is becoming increasingly important to place dwarf galaxies in a cosmological context and model their evolution in a self-consistent way. I wi...
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2023.08.08
Inferred stellar parameters from 220 million XP spectra using an empirical forward model
Gaia data release 3 (GDR3) provides a trove of 220 million low-resolution BP/RP (XP) fluxcalibrated spectra. In order to properly exploit the XP spectra, we need to accurately model them as a function of stellar type, extinction and distance. We build a machine-learning model based on the subset of XP stars with LAMOST LRS counterparts, whose stellar types are precisely determined by the higher...
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