Thesis defense of Antoine MICHEL

Thesis defense of Antoine MICHEL, PhD student in the Quantum optics group of the LCF, on Wednesday 20 December 2023 at 2pm in Auditorium of the Institut d'Optique in Palaiseau, on the topic: "Quantum simulation for electrons strongly correlated with neutral atoms: towards a simulation of materials of interest."

Abstract: "Quantum simulation holds out the promise of improving the atomic simulations used at EDF to anticipate the ageing of materials of interest. One simulator in particular seems particularly well suited to modelling interacting electrons: Rydberg atoms. The first task of this thesis is to design a variational algorithm that can be implemented on a Rydberg atom simulator for chemistry. This algorithm is specially designed for this platform and optimised by recent theoretical tools. We compare our numerical results, obtained with an emulation of a real experiment, with other approaches and show that our method is more efficient. Finally, we show that by limiting the number of measurements to make the experiment feasible on a real architecture, we can reach the fundamental energy of the H2, LiH and BeH2 molecules with 5% error. For a second algorithm, we used the 'slave' spin method to implement the physics of the 2D Fermi-Hubbard model on a Rydberg atom simulator. The idea is to decouple the degrees of freedom of charges and slave spins using a mean field to obtain two self-consistent Hamiltonians: a classically solvable one and an Ising Hamiltonian that can be reproduced on a real machine. We show numerically that we can recover a Mott transition from the initial model with this method even when emulating the noise of a real experiment, and we show that we can also recover the dynamics of non-equilibrium electrons in this same paradigm with good results. Both algorithms can be improved theoretically until they reach materials of interest, but they can also be implemented on today's existing architectures, to achieve a potential quantum advantage."