10:45
11:45

Simulating noninteracting systems of fermionic particles (such as electrons) -- so called 'free fermions' -- is a basic routine in computational many-body physics. In general, modeling free fermions on N sites needs poly(N) computational resources. While often moderate, these costs can be prohibitive in practice when large systems are considered. In this talk, I will present a few free-fermion problems that can be solved by a quantum algorithm with exponentially-improved, poly log(N) cost. Simulation of free-fermion dynamics belongs to the BQP-hard complexity class, implying that our discovered exponential speedup is robust. The key technique in our algorithm is the block-encoding of the so-called correlation matrix into a unitary. I will explain how such a unitary can be efficiently realized as a quantum circuit, in the context of free-fermion dynamics and thermal states. Finally, I will outline how our simulation algorithm generalizes to other targets such as free bosons, and potential extensions to interacting fermion simulations.
 
This talk will be based on a recent preprint arXiv:2409.04550 (under review), produced in collaboration with Maarten Stroeks, Daan Lenterman, and Barbara Terhal.

https://combalgo.labri.fr/pmwiki.php/Groupe/Info-Quantique

Room 073