Seminars & Speakers


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Defect-based quantum systems in solids
Speaker Sang-Yun Lee
Affiliation KIST
URL Link
Date September 12, 2018
Time 4:00 pm
Venue Building 110 Room N103
Sponsor UNIST-Natural Science
Host 김제형
Contact jehyungkim@unist.ac.kr
Phone 052-217-3606

High purity single crystalline solids can be used as a robust platform for quantum information research

since isolated defects, which resemble isolated single atoms when phonon coupling is efficiently

suppressed, can be created in the middle of almost noise-free environment. Among various defects

which can be created artificially, color center in wide-bandgap semiconductors such as diamond

and silicon carbide have been used to demonstrate various proof-of-idea experiments for quantum

 information and also various quantum applications such as quantum metrology. Even though small size

integrated qubit devices consisting of a few entangled spin qubits have been demonstrated, there

 remain open questions about whether this physical system will allow building large quantum devices in

which many qubits can interact with each other without losing their coherent properties.

 

Managing spin-spin interaction among defects spins near each other is a typical method to enable

quantum connection among spin qubits. In addition, the optical transitions strongly correlated with spin

states of the color centers allow another pathway for integrating individual qubits. One example is the

photonic quantum network which can meditate entanglement among distant spin qubits via spin-

selective optical transitions. The spin-to-photon interface based on a color center in diamond has shown

the entanglement rate exceeding the decoherence rate of two distant spin qubits. In parallel, there have

been efforts for finding novel color centers in various large bandgap materials whose ability as a spin-to-

photon interface may exceed that of the diamond color centers. The color centers in silicon carbide are

candidates since well-developed device fabrication techniques exist and efficient spin-to-photon

 interfaces have been found recently. In this presentation, a broad review about the quantum technology

 based on color centers in solids will be provided, and a summary about recent progresses will be presented as well.