Date and Time: 15-July-2022 15:00
Speaker: Dr. Elmer Doggen, Postdoctoral Researcher, Karlsruhe Institute of Technology (KIT), Germany.
Host: Gu Zhang(BAQIS）
Title: Generalized Quantum Measurements For Many-Body Systems With Matrix Product States
I will discuss a method , based on matrix product states, for studying the time evolution of many-body quantum lattice systems under continuous and site-resolved measurement. Both the frequency and the strength of generalized measurements can be varied within our scheme, thus allowing us to explore the corresponding two-dimensional phase diagram. The method is applied to one-dimensional chains of nearest-neighbor interacting hard-core bosons. A transition from an entangling to a disentangling (area-law) phase is found. However, by resolving time-dependent density correlations in the monitored system, we find important differences between different regions at the phase boundary. In particular, we observe a peculiar phenomenon of measurement-induced particle clusterization that takes place only for frequent moderately strong measurements, but not for strong infrequent measurements. Time permitting, I will discuss ongoing work adapting this scheme to ancilla-based measurements. 
 EVHD, Yuval Gefen, Igor V. Gornyi, Alexander D. Mirlin, Dmitry G. Polyakov, Phys. Rev. Research 4, 023146 (2022)
 EVHD et al., in preparation
About the Speaker:
Dr. Elmer V. H. Doggen is currently a Postdoctoral researcher in Karlsruhe Institute of Technology (KIT), Germany. Dr. Doggen got his Master’s degree (in applied physics) in 2011, from the group of Prof. Servaas Kokkelmans in Eindhoven University of Technology，Netherlands. After that, he moved to Aalto University in Finland, where he obtained his PhD degree (in applied physics) in 2015 under the instruction of Prof. Jami Kinnunen. He then became a Postdoctoral researcher in Université Paul Sabatier in France from 2015 to 2017. Since 2017 he joined the current institute, and worked in the group of Alexander Mirlin in Institute of Quantum Materials and Technologies of KIT. Dr. Doggen’s research interests center around the analysis of many-body localization with numerical methods including density matrix renormalization group (DMRG) technique.