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Colloquium

Non-Gaussian quantum state of multimode light generated via hybrid quantum information processing

2019-04-22
  • Speaker : Prof. Young-Sik Ra (Department of Physics, KAIST)
  • Date : 2019-05-08 16:00 ~ 17:00
  • Location : JYS 331-2
  • Host : Dr. Hyung Mok Lee (President of KASI)

Optical quantum information processing can be classified into two categories depending on the way of encoding quantum information on light: one harnesses the particle nature (photon)−called discrete-variable approach−, and the other exploits the wave nature (electric field)−called continuous-variable approach. Basic nonclassical lights for the two are single photon and squeezed vacuum, respectively. Recently, a new field of study is emerging, called hybrid quantum information processing that combines the two conventional approaches to complement each other. In this talk, I will present generation of non-Gaussian quantum states of multimode light based on the hybrid quantum information processing. Squeezed vacuum, which is employed in the continuous-variable approach, is a Gaussian state, which can be used to build a large-scale quantum system in a deterministic way. However, non-Gaussian features are required in some quantum protocols, especially to reach a quantum computation advantage. Single-photon subtraction used in the discrete-variable approach can provide the non-Gaussian characteristics. We have implemented a single-photon subtractor compatible with multimode Gaussian states and generated non-Gaussian multimode quantum states. The resulting non-Gaussian multimode quantum states will have broad applications for universal quantum computing, entanglement distillation, and a nonlocality test.