Title: Orthogonality Catastrophe as a Consequence of the Quantum Speed Limit

Speaker: Dr. Steve Campbell (UCD)

Abstract: A remarkable feature of quantum many-body systems is the orthogonality catastrophe which describes their extensively growing sensitivity to local perturbations and plays an important role in condensed matter physics. In this talk we will see that the dynamics of the orthogonality catastrophe can be understood as a direct consequence of the energy-time uncertainty relation, and as such can be fully characterized by the quantum speed limit. More specifically, we will see that any quantum many-body system whose energy scales with the number of particles exhibits the orthogonality catastrophe. Our rigorous findings are demonstrated by two paradigmatic classes of many-body systems – the trapped Fermi gas and the long-range interacting Lipkin-Meshkov-Glick spin model.

Time: Thursday, 28th November 2019, 2.30pm

Location: Lecture Room, School of Theoretical Physics, DIAS,
10 Burlington Road, Dublin 4