10 May 2019 Ceren Burçak Dağ


Speaker: Ceren Burçak Dağ, University of Michigan Ann Arbor
Title: Information scrambling in Quantum Phases
Date: May 10, 2019 (Friday)
Time: 10:30
Cookie & Tea: SCI 103 10:15
Place: SCI 103
web: https://physics-seminars.ku.edu.tr/



Out-of-time-order correlators (OTOCs) introduced a new concept to our understanding of dynamics in isolated and interacting quantum systems: information scrambling in many-body systems, that is a probe of the correlation build-up in space and time. A topic that started off to understand the information theoretic properties of black holes soon became an indicator of not only quantum chaos, but also many-body localized phase, integrability, and recently symmetry-breaking quantum phase transitions. In the first part of my talk, I will propose a disordered ladder system for scrambling detection in cold-atoms and discuss the interesting scrambling physics that this model demonstrates. Later in the second part of my talk, I will introduce a new theoretical tool that I devised to study the physics encoded in an out-of-time order correlator: dynamical decomposition method. I will show how this tool lets us analytically see the reasons and the mechanism of dynamical detection of symmetry-broken quantum phases via OTOCs. Based on the studies in literature and our numerical results in XXZ-model, our method seems to be universal in explaining the reasoning behind the relation between scrambling and the quantum criticality. In this sense, our method is an analogue of Eigenstate Thermalization Hypothesis (ETH): It tells us the criteria of how scrambling probes the criticality; though it is independent of the integrability of the system, unlike ETH. If time permits, I will talk about the extension of the method to topological phase detection via OTOCs, which brings us to explore the interplay between information scrambling and topological order.
Resources: Arxiv 1807.11085, Arxiv 1902.05041

Short Bio: Ceren B. Dag is a graduate student at the Physics Department of the University of Michigan, Ann Arbor, USA. She graduated from Istanbul Technical University in Physics and Electronics & Telecommunications Engineering. For her undergraduate thesis, she worked with Özgür E. Müstecaplıoğlu on the classification of quantum coherences based on their thermal values when they are used as fuel in micromasers. Currently she has been working with Luming Duan and Kai Sun for her PhD thesis. Her research area is quantum many-body dynamics with a focus on information scrambling, quantum criticality, dynamical phase transitions and quantum thermalization.