1. what is quantum complexity?

Alioscia Hamma

University of Massachusetts Boston, USA

23 November 2021 Tue 10 am

                                      IBS Center for Theoretical Physics of Complex Systems (PCS), Administrative Office (B349), Theory Wing, 3rd floor

                                      Expo-ro 55, Yuseong-gu, Daejeon, South Korea, 34126 Tel: +82-42-878-8633                     

How complex is a quantum state? Does the complexity of a quantum state depend on how difficult is it to make it by using elementary resources? Or a quantum state is complex if it is complex to handle? In this talk, we take the second point of view, and argue that the complexity of a quantum state depends on its pattern of entanglement. However, how much entanglement there is, is not the full story. We show that the complexity of a quantum state depends on both having a lot of entanglement and having a lot of magic, that, is, being far from a stabilizer state. We show how the interplay between entanglement and magic is responsible for the complexity of quantum states and the onset of quantum chaos.