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"Chiral Quantum Optics: Photons, atoms and qubits"

Dr. Da-Wei Wang
Department of Physics, Zhejiang University


Recently it was shown that mesoscopic superposition states of photons can be prepared based on a spin-gated chiral photon rotation in a Fock-state lattice of three cavities coupled to a spin (two-level atom) [1]. By exchanging the roles of the cavities and the spin, we have performed parallel operations on chiral spin states based on an antisymmetric spin exchange interaction (ASI) in a superconducting circuit. The ASI, which is also called Dzyaloshinskii-Moriya interaction, plays an important role in the formation of topological spin textures such as skyrmions. In the first part of the talk, I will introduce how we synthesize a chiral ASI Hamiltonian with spin-gated chiral dynamics, which allow us to demonstrate a three-spin chiral logic gate and entangle up to five qubits in Greenberger-Horne-Zeilinger states [2].

The chiral dynamics is determined by the Aharonov-Bohm phase accumulated in a closed transition loop, typically among three sites that form a triangle. A lot of such triangles can form a zigzag lattice, where chiral edge currents exist. We have observed chiral edge currents in momentum-space zigzag superradiance lattices with atoms at room temperature [3].

The chiral edge currents have been measured by comparing the directional superradiant emissions of two timed Dicke states in the lattice. This work paves the way for quantum simulation of topological matter with hot atoms and facilitates the application of topological physics in real devices.

References: [1] Da-Wei Wang, Han Cai, Renbao Liu and M. O. Scully, Phys. Rev. Lett. 116, 220502 (2016); [2] Da-Wei Wang, Chao Song, Wei Feng, Han Cai, Da Xu, Hui Deng, Dongning Zheng, Xiaobo Zhu, H. Wang, Shiyao Zhu and Marlan O. Scully, arXiv:1712.05261 (2017); [3] Han Cai, Jinhong Liu, Jinze Wu, Yanyan He, Shiyao Zhu, Junxiang Zhang and Da-Wei Wang, arXiv.1807.11111 (2018).

October 3, 2018
IQSE 578, 12:00 Noon
Mitchell Physics Building

Institute for Quantum Science and Engineering
Texas A&M University

Lunch(sandwich) will be served 15 minutes prior start time