Advith's Calendar

Abstract: A fundamental challenge in the phase diagram of the simplest atom is whether the shift of insulating liquid hydrogen H2 to metallic liquid hydrogen H at high pressures is a phase transition or merely a crossover and/or whether the critical point even exists. Since the latent heat of this transition is so low, and temperatures and pressures so extreme it required highly accurate simulations with really long run times at different atom sizes to rigorously answer this question. Thanks to the state of the art Machine Learning Interatomic Potentials (MLIPs) we were able to scale highly accurate Quantum Monte Carlo results to the thermodynamic limit and identify the critical point! 

But what physics are these MLIPs capturing so well? Could we build a purely physics based model for the simplest atom that can identify phase transitions? If so what could it tell us about these models? Hydrogen being the simplest atom allows us to explore these questions and I'd like to invite you in to this discussion.