ABSTRACT
Water boils when heated. Snowflakes melt on a warm hand. These familiar daily life experiences are examples of phase transitions in which the state of matter transform from one form to another when the thermodynamic control parameter such as the temperature varies. At absolute zero temperature, a quantum many-body system can also undergo a phase transition when varying the external driving parameter. This phenomenon is known as the quantum phase transition. To characterize a quantum phase and capture the transition point, traditionally people rely on the order parameter in the framework of Landau’s symmetry breaking theory. However, to find an appropriate order parameter that describes the transition is a highly non-trivial task in general and a prior knowledge in the symmetry of the system is required. In this talk, I will discuss how concepts from quantum information theory can help us to study quantum phase transitions without the aid of such an empirical knowledge. I will also introduce a general scheme we proposed to derive the order parameter systematically and apply it to a topological insulator with electron-electron interactions.
BIOGRAPHY
Dr. Wing Chi YU is currently a research fellow at the National University of Singapore. She obtained her Ph.D. in physics from the Chinese University of Hong Kong in 2014. After that, she continued as a postdoctoral fellow at the Chinese University of Hong Kong before moving to Singapore in 2016. Dr. Yu’s primary research interest lies in the characterization of phase transitions in quantum many-body systems. She is also interested in exploring the interplay between various phase transitions in real materials.
National University, Singapore
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