PhD defense of Pauline Besserve

Pauline Besserve will defend her thesis on Friday, October 6th in Collège de France (11 place Marcelin Berthelot, 75005 Paris.
The defense will take place in room 4 at 2pm and will be followed by a pot in room 8.

Title: Hybrid quantum-classical algorithms for the quantum many-body problem

Advisors: Michel Ferrero (Centre de Physique Théorique, Collège de France) and Thomas Ayral (Eviden Quantum Laboratory).

The thesis explores the quantum-classical implementation of the celebrated Dynamical Mean-Field Theory to study strong electronic correlations in materials. These exhibit rich phases diagrams, spanning - among others - metallic, insulating, high-Tc superconducting behaviours according to external parameters, but remain notoriously difficult to tackle due to the exponential scaling of computational resources their description involves. Quantum computers are widely hailed as promising devices to ease the bottleneck of DMFT and the first, imperfect prototypes of such devices are now becoming available. The thesis explores the use of such imperfect devices concomitantly with that of classical computational power for DMFT. It addresses both of the impediments to a quantum-classical implementation of DMFT on current devices, namely low coherence time and low qubit count, by setting forth an improved variational state preparation scheme and using hardware noise as a resource to alleviate errors inherent to the low qubit count.