Dear All,

As part of the CN1-SPOKE 10 on Quantum Computing, we are pleased to announce the last seminar before the summer break.

Title: Hybrid Quantum-Classical Krylov Methods for Eigenvalue Computation Speaker: Roel Van Beeumen (Lawrence Berkeley National Laboratory) Venue: Sala Gerace, Dipartimento di Informatica Time: Tuesday, 23/07/2024, 14:30

Abstract: Classical algorithms based on Krylov subspaces are among the most successful tools in the field of numerical linear algebra. More recently, the emergence of quantum subspace methods has resulted in a promising class of hybrid quantum-classical algorithms for eigenvalue approximation, e.g., in the fields of condensed matter physics and electronic structure theory. These quantum Krylov methods harness quantum computers to generate the subspace basis states and retrieve the projected problem through quantum measurement. However, the classical computation of the Ritz values often poses challenges due to the ill-conditioning of the associated generalized eigenvalue problem. In this talk, we present an overview of quantum subspace algorithms from a numerical linear algebra perspective. We discuss strategies to avoid solving an ill-conditioned eigenvalue problem, explain their implementation on quantum computers, and provide numerical and theoretical evidence of their convergence. Furthermore, we present strategies to improve the robustness, especially in the presence of noise.

Everyone is welcome to attend!

Gianna

@@@@@@@@@@@@@@@@@ Gianna M. Del Corso, PhD Dipartimento di Informatica, Università di Pisa Largo Pontecorvo, 3 56127 Pisa, Italy ph. +39-050-2213118 @@@@@@@@@@@@@@@@@