Postdoctoral Fellowship: MPS-Ascend: Non-equilibrium excitonic physics from real-time evolution of the two-body Green's function

Crisostomo, Steven, Irvine CA

Investigators

Abstract

Non-technical Description This award was made on an NSF Mathematical and Physical Sciences Ascending Postdoctoral Research Fellowship (NSF MPS-Ascend) proposal. Modern experiments increasingly probe quantum materials under extreme conditions, such as intense laser pulses. To keep pace, researchers need advanced simulation tools that can describe how these materials respond in real time. This project will develop new computational methods to understand excitons—bound pairs of electrons and holes—that govern how materials absorb and emit light when pushed far from equilibrium. By modeling excitons through a novel and efficient approach, this work will help explain experimental results and accelerate the design of future optoelectronic and quantum technologies. The project will also produce open-source software to support the broader research community and includes dedicated efforts to mentor students through UCSB’s Quantum Foundry program. Technical Description This award was made on an NSF Mathematical and Physical Sciences Ascending Postdoctoral Research Fellowship (NSF MPS-Ascend) proposal. This project develops a novel computational framework for simulating non-equilibrium excitonic phenomena using the real-time evolution of the two-body Green’s function (2GF). Building on the real-time Dyson expansion (RT-DE), which has been successfully applied to one-body Green’s functions, this work extends the method to capture electron-hole correlations beyond the GW approximation. The proposed approach maintains favorable computational scaling while incorporating higher-order interactions and non-equilibrium effects inaccessible to standard GW-BSE or Kadanoff-Baym approaches. Benchmarking will focus on model systems that exhibit rich excitonic physics and are relevant to current experimental efforts. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.