## Realizing a synthetic topological insulator with a quasi-periodically driven qubit

**Note:**Pizza will be served at 12:15pm

**Speaker:**Eric Boyers, Boston University

**When:**February 20, 2020 (Thu), 12:30PM to 01:30PM (add to my calendar)

**Location:**SCI 352

**Hosted by:**Eric Boyers

*This event is part of the Graduate Student Council Events. *

Part of the student seminar series

Abstract: Synthetic dimensions are a class of techniques which extend the effective dimensionality of a system by introducing additional degrees of freedom that mimic spatial dimensions and have emerged as a major area of research in recent years as a means to enrich the physics accessible by experiments. Synthetic topological systems in particular have received much attention due to the close connection between topological pumps in lower dimensions and time independent topological systems in higher dimensions, as well as their potential applications in quantum simulation and devices. While synthetic topological systems have been demonstrated in a number of platforms, few attempts have been made to realize them in few-level systems.

In this talk, I present an experimental demonstration of a synthetic topological insulator in a qubit using a quasi-periodically driven Nitrogen-vacancy center. By measuring the evolution of the overlap of states prepared at nearby points in the synthetic Brillioun zone, we perform a Loschmidt echo-like experiment which directly measures the Chern number, the topological invariant of the system. We find that the Chern number is integer quantized as expected and we use it to map out the phase diagram of the model. Our results show close agreement with theory, including an effective half-integer Chern number at a critical point in the model.